Showing papers in "Small methods in 2023"

Design Strategies toward High-Performance Zn Metal Anode.

Abstract: Rechargeable aqueous Zn-ion batteries (AZIBs) are one of the most promising alternatives for traditional energy-storage devices because of their low cost, abundant resources, environmental friendliness, and inherent safety. However, several detrimental issues with Zn metal anodes including Zn dendrite formation, hydrogen evolution, corrosion and passivation, should be considered when designing advanced AZIBs. Moreover, these thorny issues are not independent but mutually reinforcing, covering many technical and processing parameters. Therefore, it is necessary to comprehensively summarize the issues facing Zn anodes and the corresponding strategies to develop roadmaps for the development of high-performance Zn anodes. Herein, the failure mechanisms of Zn anodes and their corresponding impacts are outlined. Recent progress on improving the stability of Zn anode is summarized, including structurally designed Zn anodes, Zn alloy anodes, surface modification, electrolyte optimization, and separator design. Finally, this review provides brilliant and insightful perspectives for stable Zn metal anodes and promotes the large-scale application of AZIBs in power grid systems.

Carbon‐Based Flexible Devices for Comprehensive Health Monitoring

Abstract: Traditional public health systems suffer from incomprehensive, delayed, and inefficient medical services. Convenient and comprehensive health monitoring has been highly sought after recently. Flexible and wearable devices are attracting wide attention due to their potential applications in wearable human health monitoring and care systems. Using carbon materials with overall superiorities can facilitate the development of wearable and flexible devices with various functions and excellent performance, which can comprehensively and real‐time monitor human health status and prevent diseases. Herein, the latest advances in the rational design and controlled fabrication of carbon materials for applications in health‐related flexible and wearable electronics are reviewed. The fabrication strategies, working mechanism, performance, and applications in health monitoring of carbon‐based flexible devices, including electromechanical sensors, temperature/humidity sensors, chemical sensors, and flexible conductive wires/electrodes, are reviewed. Furthermore, integrating multiple carbon‐based devices into multifunctional wearable systems is discussed. Finally, the existing challenges and future opportunities in this field are also proposed.

Phase Evolution on the Hydrogen Adsorption Kinetics of NiFe‐Based Heterogeneous Catalysts for Efficient Water Electrolysis

Abstract: Transition metal layered double hydroxides, especially nickel‐iron layered double hydroxide (NiFe‐LDH) shows significant advancement as efficient oxygen evolution reaction (OER) electrocatalyst but also plays a momentous role as a precursor for NiFe‐based hydrogen evolution reaction (HER) catalysts. Herein, a simple strategy for developing Ni‐Fe‐derivative electrocatalysts via phase evolution of NiFe‐LDH under controllable annealing temperatures in an argon atmosphere is reported. The optimized catalyst annealed at 340 oC (denoted NiO/FeNi3) exhibits superior HER properties with an ultralow overpotential of 16 mV@10 mA cm−2. Density functional theory simulation and in situ Raman analyses reveal that the excellent HER properties of the NiO/FeNi3 can be attributed to the strong electronic interaction at the interface of the metallic FeNi3 and semiconducting NiO, which optimizes the H2O and H adsorption energies for efficient HER and OER catalytic processes. This work will provide rational insights into the subsequent development of related HER electrocatalysts and other corresponding compounds via LDH‐based precursors.

Flexible, Permeable, and Recyclable Liquid‐Metal‐Based Transient Circuit Enables Contact/Noncontact Sensing for Wearable Human–Machine Interaction

Abstract: The past several years have witnessed a rapid development of intelligent wearable devices. However, despite the splendid advances, the creation of flexible human–machine interfaces that synchronously possess multiple sensing capabilities, wearability, accurate responsivity, sensitive detectivity, and fast recyclability remains a substantial challenge. Herein, a convenient yet robust strategy is reported to craft flexible transient circuits via stencil printing liquid metal conductor on the water‐soluble electrospun film for human–machine interaction. Due to the inherent liquid conductor within porous substrate, the circuits feature high‐resolution, customized patterning viability, attractive permeability, excellent electroconductivity, and superior mechanical stability. More importantly, such circuits display appealing noncontact proximity capabilities while maintaining compelling tactile sensing performance, which is unattainable by traditional systems with compromised contact sensing. As such, the flexible circuit is utilized as wearable sensors with practical multifunctionality, including information transfer, smart identification, and trajectory monitoring. Furthermore, an intelligent human–machine interface composed of the flexible sensors is fabricated to realize specific goals such as wireless object control and overload alarm. The transient circuits are quickly and efficiently recycled toward high economic and environmental values. This work opens vast possibilities of generating high‐quality flexible and transient electronics for advanced applications in soft and intelligent systems.

High-Voltage MXene-Based Supercapacitors: Present Status and Future Perspectives.

Abstract: As an emerging class of 2D materials, MXene exhibits broad prospects in the field of supercapacitors (SCs). However, the working voltage of MXene-based SCs is relatively limited (typically ≤ 0.6 V) due to the oxidation of MXene electrode and the decomposition of electrolyte, ultimately leading to low energy density of the device. To solve this issue, high-voltage MXene-based electrodes and corresponding matchable electrolytes are developed urgently to extend the voltage window of MXene-based SCs. Herein, a comprehensive overview and systematic discussion regarding the effects of electrolytes (aqueous, organic, and ionic liquid electrolytes), asymmetric device configuration, and material modification on the operating voltage of MXene-based SCs, is presented. A deep dive is taken into the latest advances in electrolyte design, structure regulation, and high-voltage mechanism of MXene-based SCs. Last, the future perspectives on high-voltage MXene-based SCs and their possible development directions are outlined and discussed in depth, providing new insights for the rational design and realization of advanced next-generation MXene-based electrodes and high-voltage electrolytes.

Nano Delivery of Chemotherapeutic ICD Inducers for Tumor Immunotherapy

Abstract: Immunogenic cell death (ICD, also known as immunogenic apoptosis) of malignant cells is confirmed to activate the host immune system to prevent, control, and eliminate tumors. Recently, a range of chemotherapeutic drugs have been repurposed as ICD inducers and applied for tumor immunotherapy. However, several hurdles to the widespread application of chemotherapeutic ICD inducers remain, namely poor water solubility, short blood circulation, non‐specific tissue distribution, and severe toxicity. Recent advances in nanotechnology and pharmaceutical formulation foster the development of nano drug delivery systems to tackle the aforementioned hurdles and expedite safe, effective, and specific delivery. This review will describe delivery barriers to chemical ICD inducers and highlight recent nanoformulations for these drugs in tumor immunotherapy.

Structure Design for Ultrahigh Power Density Proton Exchange Membrane Fuel Cell

Abstract: Next‐generation ultrahigh power density proton exchange membrane fuel cells rely not only on high‐performance membrane electrode assembly (MEA) but also on an optimal cell structure. To this end, this work comprehensively investigates the cell performance under various structures, and it is revealed that there is unexploited performance improvement in structure design because its positive effect enhancing gas supply is often inhibited by worse proton/electron conduction. Utilizing fine channel/rib or the porous flow field is feasible to eliminate the gas diffusion layer (GDL) and hence increase the power density significantly due to the decrease of cell thickness and gas/electron transfer resistances. The cell structure combining fine channel/rib, GDL elimination and double‐cell structure is believed to increase the power density from 4.4 to 6.52 kW L−1 with the existing MEA, showing nearly equal importance with the new MEA development in achieving the target of 9.0 kW L−1.

Recent Progress on Wavelength‐Selective Perovskite Photodetectors for Image Sensing

Abstract: Spectral sensing plays a crucial part in imaging technologies, optical communication, and other fields. However, complicated optical elements, such as prisms, interferometric filters, and diffraction grating, are required for commercial multispectral detectors, which hampers their advance toward miniaturization and integration. In recent years, metal halide perovskites have been emerging for optical‐component‐free wavelength‐selective photodetectors (PDs) because of their continuously tunable bandgap, fascinating optoelectronic properties, and simple preparation processes. In this review, recent advances in wavelength‐selective perovskite PDs, including narrowband PDs, dual‐band PDs, multispectral‐recognizable PDs, and X‐ray PDs, are highlighted, with an emphasis on device structure designs, working mechanisms, and optoelectronic performances. Meanwhile, the applications of wavelength‐selective PDs in image sensing for single‐/dual‐color imaging, full‐color imaging, and X‐ray imaging are introduced. Finally, the remaining challenges and perspectives in this emerging field are presented.

High Resolution Electrochemical Imaging for Sulfur Vacancies on 2D Molybdenum Disulfide

Abstract: Molybdenum disulfide (MoS2) is considered as one of the most promising non‐noble‐metal catalysts for hydrogen evolution reaction (HER). To achieve practical application, introducing sulfur (S) vacancies on the inert basal plane of MoS2 is a widely accepted strategy to improve its HER activity. However, probing active sites at the nanoscale and quantitatively analyzing the related electrocatalytic activity in electrolyte aqueous solution are still great challenges. In this work, utilizing high‐resolution scanning electrochemical microscopy, optimized electrodes and newly designed thermal drift calibration software, the HER activity of the S vacancies on an MoS2 inert surface is in situ imaged with less than 20‐nm‐radius sensitivity and the HER kinetic data for S vacancies, including Tafel plot and onset potential, are quantitatively measured. Additionally, the stability of S vacancies over the wide range of pH 0−13 is investigated. This study provides a viable strategy for obtaining the catalytic kinetics of nanoscale active sites on structurally complex electrocatalysts and evaluating the stability of defects in different environments for 2D material‐based catalysts.

Interrelation between Programmed Cell Death and Immunogenic Cell Death: Take Antitumor Nanodrug as an Example

Abstract: Programmed cell death (PCD, mainly including apoptosis, necrosis, ferroptosis, pyroptosis, and autophagy) and immunogenic cell death (ICD), as important cell death mechanisms, are widely reported in cancer therapy, and understanding the relationship between the two is significant for clinical tumor treatments. Considering that vast nanodrugs are developed to induce tumor PCD and ICD simultaneously, in this review, the interrelationship between PCD and ICD is described using nanomedicines as examples. First, an overview of PCD patterns and focus on the morphological differences and interconnections among them are provided. Then the interrelationship between apoptosis and ICD in terms of endoplasmic reticulum stress is described by introducing various cancer treatments and the recent developments of nanomedicines with inducible immunogenicity. Next, the crosstalk between non‐apoptotic (including necrosis, ferroptosis, pyroptosis, and autophagy) signaling pathways and ICD is introduced and their relationship through various nanomedicines as examples is further illustrated. Finally, the relationship between PCD and ICD and its application prospects in the development of new ICD nanomaterials are summarized. This review is believed to deepen the understanding of the relationship between PCD and ICD, extend the biomedical applications of various nanodrugs, and promote the progress of clinical tumor therapy.

Adjusting Crystal Orientation to Promote Sodium‐Ion Transport in V5S8@Graphene Anode Materials for High‐Performance Sodium‐Ion Batteries

Abstract: Sodium‐ion batteries (SIBs) have inspired the potential for widespread use in energy storage owing to the advantages of abundant resources and low cost. Benefiting from the layered structure, 2D‐layered materials enable fast interlayer transport of sodium ions and thus are considered promising candidates as anodes for SIBs. Herein, a strategy of adjusting crystal orientation is proposed via a solvothermal method to improve sodium‐ion transport at the edge of the interlayers in 2D‐layered materials. By introducing surfactants and templates, the 2D‐layered V5S8 nanosheets are controlled to align the interlayer diffusion channels vertically to the surface, which promotes the fast transport of Na+ at the edge of the interlayers as revealed by experimental methods and ab initio calculations. Benefiting from the aligned crystal orientation and rGO coating, the vertical‐V5S8@rGO hybrid delivers a high initial discharge capacity of 350.6 mAh g−1 at a high current density of 15 A g−1. This work provides a strategy for the structural design of 2D‐layered anode materials by adjusting crystal orientation, which demonstrates the promise for applications in fast‐charging alkaline‐ion batteries.

Efficient Charge Transfer and Effective Active Sites in Lead‐Free Halide Double Perovskite S‐Scheme Heterojunctions for Photocatalytic H2 Evolution

Abstract: The practical application of lead‐free double perovskite Cs2AgBiBr6 in photocatalytic H2 evolution is still restricted due to the low activity and poor stability. The rational design of lead‐free halide double perovskites heterojunctions with efficient charge transfer and effective active sites is a potential route to achieve the ideal prospect. Herein, in this work an S‐scheme heterojunction of Cs2AgBiBr6 with enriched Br‐vacancies and WO3 nanorods (VBr‐Cs2AgBiBr6/WO3) obtaining excellent visible‐light responsive photocatalytic H2 evolution performance and durable stability is reported. The S‐scheme heterojunction driven by the unaligned Fermi levels of these two semiconductors ensures the efficient charge transfer at the interface, and density functional theory calculations reveal the enriched Br vacancies on Cs2AgBiBr6 (022) surfaces introduced by atom thermal vibration provide effective active sites for hydrogen evolution. The optimized VBr‐Cs2AgBiBr6/WO3 S‐scheme photocatalyst exhibits the photocatalytic hydrogen evolution rate of 364.89 µmol g−1 h−1 which is 4.9‐fold of bare VBr‐Cs2AgBiBr6 (74.44 µmol g−1 h−1) and presents long‐term stability of 12 h continuous photocatalytic reaction. This work provides deep insights into the photocatalytic mechanism of VBr‐Cs2AgBiBr6/WO3 S‐scheme heterojunctions, which emerges a new strategy in the applications of perovskite‐based photocatalysts.

Porous Graphene Produced by Carbothermal Shock for Green Electromagnetic Interference Shielding in Both Microwave and Terahertz Bands

Abstract: The prospect of graphene‐based shielding materials in the form of fillers is limited by the cumbersome preparation of graphene. Herein, defect‐tunable porous graphene prepared by carbothermal shock using low‐value sucrose as a precursor is proposed as an effective shielding filler. The resultant porous graphene exhibits 32.5 dB shielding efficiency (SE) and 2.5–18 GHz effective bandwidth at a mass loading of 20 wt%, competing with the shielding performance of graphene fillers prepared by other methods. Particularly, defect‐rich graphene synthesized by increasing voltage and prolonging time shows increased electromagnetic (EM) wave absorption, echoing the current concept of green shielding. In addition, the strategy of controlling the discharge conditions to improve the absorption by the shield is developed in the terahertz band. The average SE and reflection loss of the samples in the THz band (0.2–1.2 THz) exhibit 40.7 and 15.9 dB at filler loading of 5 wt%, respectively, achieving effective shielding and absorption of THz waves. This work paves a new way for low‐cost preparation of graphene for EM interference shielding fillers. Meanwhile, it supplies a reference for the shielding research of the upcoming applications integrating multiple EM bands (such as sixth‐generation based integrated sensing and communication).

Noncrystalline Carbon Anodes for Advanced Sodium‐Ion Storage

Abstract: Developing an anode with excellent rate performance, long‐cycle stability, high coulombic efficiency, and high specific capacity is one of the key research directions of sodium‐ion batteries. Among all the anode materials, noncrystalline carbon (NCC) has great possibilities according to its supreme performance and low cost, but with the complexity and variability of the structure. With the in‐depth study of the sodium storage behaviors of NCC in recent years, three modes of interlayer intercalation, clustering into micropores, and adsorption are reported and summarized. Although the storage mechanism has gradually become more evident, the complex behavior of the ions at different voltage regions, especially in the low‐voltage (plateau) region, still remains controversial. It is essential to understand further the relationship between ions and NCC structure during energy storage processes. Based on the summary of previous works, this article has reviewed the storage mechanism of sodium ions in NCC and evaluated the structure–behavior relationship between sodium‐ion storage and the carbon structure.

Polydopamine‐Decorated PLCL Conduit to Induce Synergetic Effect of Electrical Stimulation and Topological Morphology for Peripheral Nerve Regeneration

Abstract: Due to the limited self‐repairing capacity after peripheral nerve injuries (PNI), artificial nerve conduits are widely applied to facilitate neural regeneration. Exogenous electrical stimulation (ES) that is carried out by the conductive conduit regulates the biological behavior of Schwann cells (SCs). Meanwhile, a longitudinal surface structure counts to guide axonal growth to accelerate the end‐to‐end connection. Currently, there are no conduits equipped with both electrical conduction and axon‐guiding surface structure. Herein, a biodegradable, conductive poly(l‐lactide‐co‐caprolactone)/graphene (PLCL/GN) composite conduit is designed. The conduit with 20.96 ± 1.26 MPa tensile strength has a micropatterned surface of 20 µm groove fabricated by microimprint technology and self‐assembled polydopamine (PDA). In vitro evaluation shows that the conduits with ES effectively stimulate the directional cell migration, adhesion, and elongation, and enhance neuronal expression of SCs. The rat sciatic nerve crush model demonstrates that the conductive micropatterned conduit with ES promotes the growth of myelin sheath, faster nerve regeneration, and 20‐fold functional recovery in vivo. These discoveries prove that the PLCL(G)/PDA/GN composite conduit is a promising tool for PNI treatment by providing the functional integration of physical guidance, biomimetic biological regulation, and bioelectrical stimulation, which inspires a novel therapeutic approach for nerve regeneration in the future.

High Mobility IZTO Thin‐Film Transistors Based on Spinel Phase Formation at Low Temperature through a Catalytic Chemical Reaction

Abstract: In this paper, In0.22ZnδSn0.78−δO1.89−δ (δ = 0.55) films with a single spinel phase are successfully grown at the low temperature of 300 °C through careful cation composition design and a catalytic chemical reaction. Thin‐film transistors (TFTs) with amorphous In0.22ZnδSn0.78−δO1.89−δ (δ = 0.55) channel layers have a reasonable mobility of 41.0 cm2 V−1 s−1 due to the synergic intercalation of In and Sn ions. In contrast, TFTs with polycrystalline spinel In0.22ZnδSn0.78−δO1.89−δ (δ = 0.55) channel layers, achieved through a metal‐induced crystallization at 300 °C, exhibit a remarkably high field‐effect mobility of ≈83.2 cm2 V−1 s−1 and excellent stability against external gate bias stress, which is attributed to the uniform formation of the highly ordered spinel phase. The relationships between cation composition, microstructure, and performance for the In2O3–ZnO–SnO2 ternary component system are investigated rigorously to attain in‐depth understanding of the roles of various crystalline phases, including spinel Zn2−ySn1−yIn2yO4 (y = 0.45), bixbyite In2−2xZnxInxO4 (x = 0.4), rutile SnO2, and a homologous compound of compound (ZnO)k(In2O3) (k = 5). This work concludes that the cubic spinel phase of Zn2−ySn1−yIn2yO4 (y = 0.45) film is a strong contender as a substitute for semiconducting polysilicon as a backplane channel ingredient for mobile active‐matrix organic light‐emitting diode displays.

Effect of Substitutional Oxygen on Properties of Ti3 C2 Tx MXene Produced Using Recycled TiO2 Source.

Abstract: MXenes are an emerging class of 2D materials with unique properties including metallic conductivity, mechanical flexibility, and surface tunability, which ensure their utility for diverse applications. However, the synthesis of MXenes with high crystallinity and atomic stoichiometry in a low-cost process is still challenging because of the difficulty in controlling the oxygen substitute in the precursors and final products of MXenes, which limits their academic understanding and practical applications. Here, a novel cost-effective method is reported to synthesize a highly crystalline and stoichiometric Ti3 C2 Tx MXene with minimum substitutional oxygen impurities by controlling the amount of excess carbon and time of high-energy milling in carbothermal reduction of recycled TiO2 source. The highest used content (2 wt%) of excess-carbon yields TiC with the highest carbon content and minimal oxygen substitutes, which leads to the Ti3 AlC2 MAX phase with improved crystallinity and atomic stoichiometry, and finally Ti3 C2 Tx MXene with the highest electrical conductivity (11738 S cm-1 ) and superior electromagnetic shielding effectiveness. Additionally, the effects of carbon content and substitutional oxygen on the physical properties of TiC and Ti3 AlC2 are elucidated by density-functional-theory calculations. This inexpensive TiO2 -based method of synthesizing high-quality Ti3 C2 Tx MXene can facilitate large-scale production and thus accelerate global research on MXenes.

Construction of Localized High‐Concentration PF6− Region for Suppressing NCM622 Cathode Failure at High Voltage

Abstract: High‐voltage Li||LiNi0.6Co0.6Mn0.2O2 (NCM622) batteries have obtained great interest owing to their high energy density. However, some obstacles hinder their practical applications, e.g., the structural failure of NCM622 and corrosion of the Al current collector, which lead to limited cycling life. Herein, an electrolyte additive strategy is proposed for constructing localized high‐concentration PF6− zone near the cathode to form an efficient cathode electrolyte interphase (CEI) for protecting NCM622 and preventing Al current collector from the corrosion. Potassium 1,1,2,2,3,3‐hexafluoropropane‐1,3‐disulfonimide is used as the additive to regulate the sheath structure of Li+ solvation to force PF6− anions away from the solvated Li+. During the charge process, the nonsolvated PF6− anions gather on NCM622 surface to form a localized high‐concentration PF6− zone to facilitate the formation of F‐rich CEI on NCM622 for protecting its structural stability and Al current collector.

Non‐Invasive and Minute‐Frequency 3D Tomographic Imaging Enabling Long‐Term Spatiotemporal Observation of Single Cell Fate

Abstract: Non‐invasive and rapid imaging technique at subcellular resolution is significantly important for multiple biological applications such as cell fate study. Label‐free refractive‐index (RI)‐based 3D tomographic imaging constitutes an excellent candidate for 3D imaging of cellular structures, but its full potential in long‐term spatiotemporal cell fate observation is locked due to the lack of an efficient integrated system. Here, a long‐term 3D RI imaging system incorporating a cutting‐edge white light diffraction phase microscopy module with spatiotemporal stability, and an acoustofluidic device to roll and culture single cells in a customized live cell culture chamber is reported. Using this system, 3D RI imaging experiments are conducted for 250 cells and demonstrate efficient cell identification with high accuracy. Importantly, long‐term and frequency‐on‐demand 3D RI imaging of K562 and MCF‐7 cancer cells reveal different characteristics during normal cell growth, drug‐induced cell apoptosis, and necrosis of drug‐treated cells. Overall, it is believed that the proposed 3D tomographic imaging technique opens up a new avenue for visualizing intracellular structures and will find many applications such as disease diagnosis and nanomedicine.

Step-by-Step Guide for Synthesis and Delamination of Ti3 C2 Tx MXene.

Abstract: To advance the MXene field, it is crucial to optimize each step of the synthesis process and create a detailed, systematic guide for synthesizing high-quality MXene that can be consistently reproduced. In this study, a detailed guide is provided for an optimized synthesis of titanium carbide (Ti3 C2 Tx ) MXene using a mixture of hydrofluoric and hydrochloric acids for the selective etching of the stoichimetric-Ti3 AlC2 MAX phase and delamination of the etched multilayered Ti3 C2 Tx MXene using lithium chloride at 65 °C for 1 h with argon bubbling. The effect of different synthesis variables is investigated, including the stoichiometry of the mixed powders to synthesize Ti3 AlC2 , pre-etch impurity removal conditions, selective etching, storage, and drying of MXene multilayer powder, and the subsequent delamination conditions. The synthesis yield and the MXene film electrical conductivity are used as the two parameters to evaluate the MXene quality. Also the MXenes are characterized with scanning electron microscopy, x-ray diffraction, atomic force microscopy, and ellipsometry. The Ti3 C2 Tx film made via the optimized method shows electrical conductivity as high as ≈21,000 S/cm with a synthesis yield of up to 38 %. A detailed protocol is also provided for the Ti3 C2 Tx MXene synthesis as the supporting information for this study.

Spin‐Selective Coupling in Mott–Schottky Er2O3‐Co Boosts Electrocatalytic Oxygen Reduction

Abstract: Alkaline oxygen reduction reaction (ORR) is critical to electrochemical energy conversion technology, yet the rational breaking of thermodynamic inhibition for ORR through spin regulation remains a challenge. Herein, a Mott–Schottky catalyst consisting of Er2O3‐Co particles uniformly implanted into carbon nanofibers (Er2O3‐Co/CNF) is designed for enhancing ORR via spin‐selective coupling. The optimized Er2O3‐Co/CNF affords a high half‐wave potential (0.835 V vs reversible hydrogen electrode, RHE) and onset potential (0.989 VRHE) for the ORR surpassing individual Co/CNF and Er2O3/CNF. Theoretical calculations reveal the introduction of Er2O3 optimizes the electronic structure of Co through Er(4f)‐O(2p)‐Co(3d) gradient orbital coupling, resulting in significantly enhanced ORR performance. Through gradient orbital coupling, the induced spin‐up hole in Co 3d states endows the Er‐O‐Co unit active site with a spin‐selective coupling channel for electron transition. This favors the decrease of the energy gap in the potential‐limiting step, thus achieving a high theoretical limiting potential of 0.77 VRHE for the Er2O3‐Co. Moreover, the potential practicability of Er2O3‐Co/CNF as an air‐cathode is also demonstrated in Zn‐air batteries. This work is believed to provide, new perspectives for the design of efficient ORR electrocatalysts by engineering spin‐selective coupling induced by rare‐earth oxides.

Reexamining the Post‐Treatment Effects on Perovskite Solar Cells: Passivation and Chloride Redistribution

Abstract: Post‐treatment is an essential passivation step for the state‐of‐the‐art perovskite solar cells (PSCs) but the additional role is not yet exploited. In this work, perovskite film is fabricated under ambient air with wide humidity window and identify that chloride redistribution induced by post‐treatment plays an important role in high performance. The chlorine/iodine ratio on the perovskite surface increases from 0.037 to 0.439 after cyclohexylmethylammonium iodide (CHMAI) treatment and the PSCs deliver a champion power conversion efficiency (PCE) of 24.42% (certificated 23.60%). The maximum external quantum efficiency of electroluminescence (EQEEL) reaches to 10.84% with a radiance of 170 W sr−1 m−2, forming the reciprocity relation between EQEEL and nonradiative open‐circuit voltage loss (86.0 mV). After thermal annealing, 2D component of perovskite will increase while chloride decline, leading to improved photovoltage but reduced fill factor. Hence, it distinguishes that chloride enrichment can improve charge transport/recombination simultaneously and 2D passivation can suppress the nonradiative recombination. Moreover, CHMAI can leverage their roles in charge transport/recombination for better performance than phenylethylammonium iodide (Cl/I = 0.114, PCE = 23.32%), due to the stronger binding energy of Cl−. This work provides the insight that the chloride fixation can improve the photovoltaic performance.

Photocatalytic Activity of the Oxidation Stabilized Ti3 C2 Tx MXene in Decomposing Methylene Blue, Bromocresol Green and Commercial Textile Dye.

Abstract: Two-dimensional MXenes are excellent photocatalysts. However, their low oxidation stability makes controlling photocatalytic processes challenging. For the first time, this work elucidates the influence of the oxidation stabilization of model 2D Ti3 C2 Tx MXene on its optical and photocatalytic properties. The delaminated MXene is synthesized via two well-established approaches: hydrofluoric acid/tetramethylammonium hydroxide (TMAOH-MXene) and minimum intensive layer delamination with hydrochloric acid/lithium fluoride (MILD-MXene) and then stabilized by L-ascorbic acid. Both MXenes at a minimal concentration of 32 mg L-1 show almost 100% effectiveness in the 180-min photocatalytic decomposition of 25 mg L-1 model methylene blue and bromocresol green dyes. Industrial viability is achieved by decomposing a commercial textile dye having 100 times higher concentration than that of model dyes. In such conditions, MILD-MXene is the most efficient due to less wide optical band gap than TMAOH-MXene. The MILD-MXene required only few seconds of UV light, simulated white light, or 500 nm (cyan) light irradiation to fully decompose the dye. The photocatalytic mechanism of action is associated with the interplay between surface dye adsorption and the reactive oxygen species generated by MXene under light irradiation. Importantly, both MXenes are successfully reused and retained approximately 70% of their activity.

Theoretical Prediction of Thermoelectric Performance for Layered LaAgOX (X = S, Se) Materials in Consideration of the Four‐Phonon and Multiple Carrier Scattering Processes

Abstract: Inspired by the experimental achievement of layered LaCuOX (X = S, Se) with superior thermoelectric (TE) performance, the TE properties of Ag‐based isomorphic LaAgOX are systemically investigated by the first‐principles calculation. The LaAgOS and LaAgOSe are direct semiconductors with wide bandgaps of ≈2.50 and ≈2.35 eV. Essential four‐phonon and multiple carrier scattering mechanisms are considered in phonon and electronic transport calculations to improve the accuracy of the figure‐of‐merit (ZT). The p‐type LaAgOX (X = S, Se) shows excellent TE performance on account of the large Seebeck coefficient originated from the band convergency and low thermal conductivity caused by the strong phonon–phonon scattering. Consequently, the optimal ZTs along the out‐of‐plane direction decrease in the order of n‐type LaAgOSe (≈2.88) > p‐type LaAgOSe (≈2.50) > p‐type LaAgOS (≈2.42) > n‐type LaAgOS (≈2.27) at 700 K, and the optimal ZTs of ≈1.16 and ≈1.29 are achieved for p‐type LaAgOS and LaAgOSe at the same temperature. The present work would provide a deep insight into the phonon and electronic transport properties of LaAgOX (X = S, Se), but also could shed light on the way for the rational design of state‐of‐the‐art heteroanionic materials for TE application.

Cancer Immunotherapy Elicited by Immunogenic Cell Death Based on Smart Nanomaterials

Abstract: Cancer immunotherapy has been a revolutionary cancer treatment modality because it can not only eliminate primary tumors but also prevent metastases and recurrent tumors. Immunogenic cell death (ICD) induced by various treatment modalities, including chemotherapy, phototherapy, and radiotherapy, converts dead cancer cells into therapeutic vaccines, eliciting a systemic antigen‐specific antitumor. However, the outcome effect of cancer immunotherapy induced by ICD has been limited due to the low accumulation efficiency of ICD inducers in the tumor site and concomitant damage to normal tissues. The boom in smart nanomaterials is conducive to overcoming these hurdles owing to their virtues of good stability, targeted lesion site, high bioavailability, on‐demand release, and good biocompatibility. Herein, the design of targeted nanomaterials, various ICD inducers, and the applications of nanomaterials responsive to different stimuli, including pH, enzymes, reactive oxygen species, or dual responses are summarized. Furthermore, the prospect and challenges are briefly outlined to provide reference and inspiration for designing novel smart nanomaterials for immunotherapy induced by ICD.

In Situ/Operando Methods for Understanding Electrocatalytic Nitrate Reduction Reaction

Abstract: With the development of industrial and agricultural, a large amount of nitrate is produced, which not only disrupts the natural nitrogen cycle, but also endangers public health. Among the commonly used nitrate treatment techniques, the electrochemical nitrate reduction reaction (eNRR) has attracted extensive attention due to its mild conditions, pollution‐free nature, and other advantages. An in‐depth understanding of the eNRR mechanism is the prerequisite for designing highly efficient electrocatalysts. However, some traditional characterization tools cannot comprehensively and deeply study the reaction process. It is necessary to develop in situ and operando techniques to reveal the reaction mechanism at the time‐resolved and atomic level. This review discusses the eNRR mechanism and summarizes the possible in situ techniques used in eNRR. A detailed introduction of various in situ techniques and their help in understanding the reaction mechanism is provided. Finally, the current challenges and future opportunities in this research area are discussed and highlighted.

Understanding and Optimizing Capacitance Performance in Reduced Graphene‐Oxide Based Supercapacitors

Abstract: Reduced graphene‐oxide (RGO)‐based electrodes in supercapacitors deliver high energy/power capacities compared to typical nanoporous carbon materials. However, extensive critical analysis of literature reveals enormous discrepancies (up to 250 F g−1) in the reported capacitance (variation of 100–350 F g−1) of RGO materials synthesized under seemingly similar methods, inhibiting an understanding of capacitance variation. Here, the key factors that control the capacitance performance of RGO electrodes are demonstrated by analyzing and optimizing various types of commonly applied electrode fabrication methods. Beyond usual data acquisition parameters and oxidation/reduction properties of RGO, a substantial difference of more than 100% in capacitance values (with change from 190 ± 20 to 340 ± 10 F g−1) is found depending on the electrode preparation method. For this demonstration, ≈40 RGO‐based electrodes are fabricated from numerous distinctly different RGO materials via typically applied methods of solution (aqueous and organic) casting and compressed powders. The influence of data acquisition conditions and capacitance estimation practices are also discussed. Furthermore, by optimizing electrode processing method, a direct surface area governed capacitance relationship for RGO structures is revealed.

Reducing Carbonaceous Salts for Facile Fabrication of Monolayer Graphene

Abstract: Novel methods and mechanisms for graphene fabrication are of great importance in the development of materials science. Herein, a facile method to directly convert carbonaceous salts into high‐quality freestanding graphene via a simple one‐step redox reaction, is reported. The redox couple can be a combination of sodium borohydride (reductant) and sodium carbonate (oxidant), which can readily react with each other when evenly mixed/calcined and yield gram‐scale, high‐quality, contamination‐free, micron‐sized, freestanding graphene. More importantly, this method is applicable to a variety of input reductants and oxidants that are low cost and easily accessible. An in‐depth investigation reveals that the carbonaceous oxidants can not only provide reduced carbon mass for graphene formation but also act as a self‐template to guide the polymerization of carbon atoms following the pattern of the monolayer, six‐carbon rings. In addition, the direct formation of graphene exhibits theoretically lower energy barriers than that of other allotropes such as fullerene and carbon nanotube. This facile, low‐cost, scalable, and applicable method for mass production of high‐quality graphene is expected to revolutionize graphene fabrication technology and boost its practical application to the industry level.

Reduced VOC Deficit of Mixed Lead–Tin Perovskite Solar Cells via Strain‐Releasing and Synergistic Passivation Additives

Abstract: The power conversion efficiency (PCE) of tin–lead perovskite solar cells (PSCs) is normally lower than that of Pb cells, mainly due to greater open circuit voltage (VOC) losses. Herein, the additive 2,6‐diaminopyridine (TNPD) is designed to anchor on the surface of the perovskite precursor colloid as nucleating agent to modulate the growth of Pb–Sn perovskites. It is observed that the TNPD not only effectively induces crystal growth during the nucleation stage, remaining on the crystal surface and ultimately passivating the resulting perovskite films, but also releases the micro‐strain generated during the film growth. Furthermore, TNPD could lower the defect density (Sn4+ amount) by screening the perovskite against oxygen and by synergistically bonding with undercoordinated Sn/Pb on the surface. Finally, a high VOC of 0.85 V is obtained, corresponding to a voltage deficit of 0.41 V using a perovskite absorber with a bandgap of 1.26 eV, and a high PCE (20.35%) reported so far for Pb–Sn PSCs. Moreover, the stability of the TNPD‐incorporated device is significantly improved, and the PCE maintains 50% of the initial value after about 1000 h storage in glovebox without encapsulated, in comparison to that of the control device (about 700 h, maintaining 30% of the initial value).

Confined Bismuth–Organic Framework Anode for High‐Energy Potassium‐Ion Batteries

Abstract: Metal–organic frameworks (MOFs) with inherent porosity, controllable structures, and designable components are recognized as attractive platforms for designing advanced electrodes of high‐performance potassium‐ion batteries (PIBs). However, the poor electrical conductivity and low theoretical capacity of many MOFs lead to inferior electrochemical performance. Herein, for the first time, a confined bismuth–organic framework with 3D porous matrix structure (Bi‐MOF) as anode for PIBs via a facile wet‐chemical approach is reported. Such a porous structure design with double active centers can simultaneously ensure the structure integrity and efficient charge transport to enable high‐capacity electrode with super cycling life. As a result, the Bi‐MOF for PIBs exhibits high reversible capacity (419 mAh g−1 at 0.1 A g−1), outstanding cycling stability (315 mAh g−1 at 0.5 A g−1 after 1200 cycles), and excellent full battery performance (a high energy density of 183 Wh kg−1 is achieved, outperforming all reported metal‐based anodes for PIBs). Moreover, the K+ storage mechanisms of the Bi‐MOF are further unveiled by in situ Raman, ex situ high‐resolution transmission electron microscopy, and ex situ Fourier‐transform infrared spectroscopy. This ingenious electrode design may provide further guidance for the application of MOF in energy storage systems.