Despite substantial progress in the development of wearable and flexible monitoring systems that conform to the epidermis, most designs focus on either physiological signs such as the electrocardiogram (ECG) results, respiration rate, or metabolites, and ignore the dynamic fluctuations of pH and temperature in sweat during on‐body tests. An advanced butterfly‐inspired hybrid epidermal biosensing (bi‐HEB) patch is presented here, which is interfaced with a custom‐developed miniaturized monitoring system. The patch incorporates a novel transducing layer of nanoporous carbon and MXene (NPC@MXene) for sensitive and durable detection of biomarkers in sweat. The bi‐HEB patch is composed of a glucose biosensor accompanied by pH and temperature sensors to precisely quantify glucose as well as two biopotential electrodes, allowing real‐time recording of electrophysiological (EP) signals. The NPC@MXene‐based glucose biosensor demonstrates an excellent sensitivity of 100.85 µAmm−1 cm−2 within physiological levels (0.003−1.5 mm), and variations in pH and temperature during on‐body perspiration monitoring are calibrated by employing a correction approach. In parallel, the EP electrodes exhibit skin‐electrode contact impedance and biopotential signals similar to those of conventional Ag/AgCl electrodes. Finally, the bi‐HEB patch integrated wearable system is used to accurately monitor sweat glucose and ECG of human subjects participating in indoor physical activities.

A Nanoporous Carbon‐MXene Heterostructured Nanocomposite‐Based Epidermal Patch for Real‐Time Biopotentials and Sweat Glucose Monitoring

Metal-organic frameworks (MOFs) with diverse composition, tunable structure, and unique physicochemical properties have emerged as promising materials in various fields. The tunable pore structure, abundant active sites, and ultrahigh specific surface area can facilitate mass transport and provide outstanding capacity, making MOFs an ideal active material for electrochemical energy storage and conversion. However, the poor electrical conductivity of pristine MOFs severely limits their applications in electrochemistry. Developing conductive MOFs has proved to be an effective solution to this problem. This review focuses on the design and synthesis of conductive MOF composites with judiciously chosen conducting materials, pristine MOFs, and assembly methods, as well as the preparation of intrinsically conductive MOFs based on building 2D π-conjugated structures, introducing mixed-valence metal ions/redox-active ligands, designing π-π stacked pathways, and constructing infinite metal-sulfur chains (-M-S-)∞ . Furthermore, recent progress and challenges of conductive MOFs for energy storage and conversion (supercapacitors, Li-ion batteries, Li-S batteries, and electrochemical water splitting) are summarized.

Recent Progress of Advanced Conductive Metal-Organic Frameworks: Precise Synthesis, Electrochemical Energy Storage Applications, and Future Challenges.

Triboelectric nanogenerators (TENGs) have intrigued scientists for their potential to alleviate the energy shortage crisis and facilitate self-powered sensors. Triboelectric interfaces containing triboelectric functionalized molecular groups and tunable surface charge densities are important for improving the electrical output capability of TENGs and the versatility of future electronics. In this review, following an introduction to the fundamental progress of TENG systems for mechanic energy harvesting, surface modifications that aim to increase the surface charge density and functionality are highlighted, with an emphasis on interfacial chemical modification and triboelectric energetics/dynamics optimization for efficient electrostatic induction and charge transfer. Recent advances in assemblies of multifunctional triboelectric sensing are briefly introduced, and future challenges and chemical perspectives in the field of TENG-based electronics are concisely reviewed. This review presents and advances the understanding of the state-of-the-art chemical strategies toward rational triboelectric interface engineering and system assembly and is expected to guide the rational design of highly efficient and versatile triboelectric sensing.

From Triboelectric Nanogenerator to Multifunctional Triboelectric Sensors: A Chemical Perspective toward the Interface Optimization and Device Integration.

MXene-based materials for advanced nanogenerators

The rapid rise of triboelectric nanogenerators (TENGs), which are emerging energy conversion devices in advanced electronics and wearable sensing systems, has elevated the interest in high‐performance and multifunctional triboelectric materials. Among them, cellulosic materials, affording high efficiency, biodegradability, and customizability, are becoming a new front‐runner. The inherently low dielectric constant limits the increase in the surface charge density. However, owing to its unique structure and excellent processability, cellulose shows great potential for dielectric modulation, providing a strong impetus for its advanced applications in the era of Internet of Things and artificial intelligence. This review aims to provide comprehensive insights into the fabrication of dielectric‐enhanced cellulosic triboelectric materials via dielectric modulation. The exceptional advantages and research progress in cellulosic materials are highlighted. The effects of the dielectric constant, polarization, and percolation threshold on the charge density are systematically investigated, providing a theoretical basis for cellulose dielectric modulation. Typical dielectric characterization methods are introduced, and their technical characteristics are analyzed. Furthermore, the performance enhancements of cellulosic triboelectric materials endowed by dielectric modulation, including more efficient energy harvesting, high‐performance wearable electronics, and impedance matching via material strategies, are introduced. Finally, the challenges and future opportunities for cellulose dielectric modulation are summarized.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/advs.202206243

Fabrication of Advanced Cellulosic Triboelectric Materials via Dielectric Modulation

Enhanced energy harvesting performance of triboelectric nanogenerator via efficient dielectric modulation dominated by interfacial interaction

Enhanced Energy Harvesting Performance of Triboelectric Nanogenerator via Efficient Dielectric Modulation Dominated by Interfacial Interaction

Decades of extensive research efforts by scientists in the field of catalysis and nanomaterials have led to a large number of excellent bimetallic nanocatalysts. However, in many cases, the mechanism of the synergistic effect in bimetal catalyst-catalyzed reactions has been systematically neglected due to technical limitations. Herein, we use single-molecule fluorescence microscopy (SMFM) to reveal the mechanism of the synergy of the Au and Ag bimetal catalyst. Compared with that of the Ag nanocatalyst, the incorporation of Au changes the reaction pathway of Amplex Red and H2O2 from a noncompetitive to a competitive reaction mechanism, showing much higher catalytic efficiency. Additionally, the incorporation also inhibits the spontaneous surface reconstruction and facilitates the reaction-induced surface restructuring of the nanocatalyst, resulting in the enhancement of stability and reactivity. These findings provide useful insights into tailoring the reactivity of metal catalysts. This work also confirms the power of SMFM in revealing the origin of the catalytic activity of composite catalysts. 

Single-Molecule Nanocatalysis Reveals the Kinetics of the Synergistic Effect Based on Single-AuAg Bimetal Nanocatalysts

The conductive metal organic framework (MOF) discloses efficient electron transfer ability and its specific framework structure could realize ion recognition. The state-of-the-art solid-contact ion-selective electrodes (SC-ISEs) rely on both solid contact (SC) and ion-selective membrane (ISM) for respective functions of ion-to-electron transduction and ion recognition. Herein, we report an ISM-free SC-ISE by using the conductive MOF of Cu3(HHTP)2 (Cu as metallic nodes and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) as triphenylene-based organic linkers) as a bifunctional role of SC and ISM for Cu2+ sensing. The experimental results demonstrated a Nernstian and selective response to Cu2+ with a slope of 29.5 ± 0.3 mV dec−1. Compared with traditional Cu2+-ISM-based SC-ISEs, the potentiometric response time has been greatly reduced from ∼ 50 s to 10 s. Moreover, the ISM-free conductive MOF could offer normal potentiometric responses even under a short conditioning time in solution (minutes). In addition, organic solvent tolerance has also been proved for the ISM-free conductive MOF-based SC-ISE. This work demonstrates that the MOF could be feasible for constructing a type of ISM-free solid potentiometric ion sensors. 

Gert Tinggaard Svendsen

Papers

Enhanced energy harvesting performance of triboelectric nanogenerator via efficient dielectric modulation dominated by interfacial interaction

Enhanced Energy Harvesting Performance of Triboelectric Nanogenerator via Efficient Dielectric Modulation Dominated by Interfacial Interaction

Single-Molecule Nanocatalysis Reveals the Kinetics of the Synergistic Effect Based on Single-AuAg Bimetal Nanocatalysts

Conductive metal organic framework for ion-selective membrane-free solid-contact potentiometric Cu2+ sensing

Hallucinating uncertain motion and future for static image action recognition