Showing papers by "Xiaobin Fan published in 2021"
TL;DR: In this article, a novel activator is successfully synthesized with single iron atoms anchored on porous N-doped carbon (Fe-N-PC) by a facile chemical vapor deposition (CVD) method.
Abstract: Fenton-like reactions with persulfates as the oxidants have attracted increasing attentions for the remediation of emerging antibiotic pollutions. However, developing effective activators with outstanding activities and long-term stabilities remains a great challenge in these reactions. Herein, a novel activator is successfully synthesized with single iron atoms anchored on porous N-doped carbon (Fe-N-PC) by a facile chemical vapor deposition (CVD) method. The single Fe atoms are coordinated with four N atoms according to the XANES, and the Fe-N4 -PC shows enhanced activity for the activation of peroxymonosulfate (PMS) to degrade sulfamethoxazole (SMX). The experiments and density functional theory (DFT) calculations reveal that the introduction of single Fe atoms will regulate the main active sites from graphite N into Fe-N4 , thus could enhance the stability and tune the PMS activation pathway from non-radical into radical dominated process. In addition, the N atoms connected with single Fe atoms in the Fe-N4 -C structure can be used to enhance the adsorption of organic molecules on these materials. Therefore, the Fe-N4 -C here has dual roles for antibiotics adsorption and PMS activation. The CVD synthesized Fe-N4 -C shows enhanced performance in persulfates based Fenton-like reactions, thus has great potential in the environmental remediation field.
80 citations
TL;DR: In this article, a series of Co@N-C materials are synthesized using nitrates (LiNO3, NaNO3 and KNO3) as templates to control the preferential growth of the cobalt (200) facet.
Abstract: Herein, a series of Co@N–C materials are synthesized using nitrates (LiNO3, NaNO3, and KNO3) as templates to control the preferential growth of the cobalt (200) facet. Co@N–C–X (X = LiNO3, NaNO3, a...
68 citations
TL;DR: In this article, Nitrogen and sulfur co-doped graphene (N,S-G) is activated using ZnCl2, KOH, and CO2 to develop different defects and functionalities.
Abstract: Nitrogen and sulfur co-doped graphene (N,S-G) is activated using ZnCl2, KOH, and CO2 to develop different defects and functionalities. The modified carbo-catalysts are used to activate peroxymonosu...
59 citations
TL;DR: In this article, single iron atoms are anchored on three-dimensional N-doped carbon nanosheets by a chemical vapor deposition (CVD) method with ferrocene-loaded CaO as the hard template.
Abstract: Persulfate-based advanced oxidation processes are promising technologies to solve water pollution. In this work, single iron atoms are anchored on three-dimensional N-doped carbon nanosheets by a chemical vapor deposition (CVD) method with ferrocene-loaded CaO as the hard template. The high surface density of Fe–N4 sites and abundant interconnected meso–macro pores are highly favorable for activating peroxymonosulfate (PMS) to produce superoxide radicals (O2˙−), giving rise to ultrahigh activity and excellent stability for pollutant degradation. Experiment and density functional theory (DFT) calculations reveal that Fe–N4 is the main active site, on which electrons transfer from C to Fe via the C–N–Fe bond to secure the low-valence state of Fe species for the redox process. This work proposes a new strategy for developing highly active single-atom materials by CVD and reveals mechanisms of PMS activation on single-atom activators.
53 citations
TL;DR: In this article, an effective in situ hybridization method to prepare spindle-like vanadium disulfide (VS2) nanocrystals on a nitrogen doped carbon (N-doped carbon) layer was proposed and systematically explored its electrochemical property as the cathode material for rechargeable aqueous zinc-ion (Znion) batteries.
Abstract: Recently, rechargeable aqueous batteries have been regarded as a potential candidate for large-scale energy storage due to their intrinsic low cost, high operational safety, and environmental benignancy. Herein, we report an effective in situ hybridization method to prepare spindle-like vanadium disulfide (VS2) nanocrystals on a nitrogen doped carbon (N-doped carbon) layer (VS2@N–C) and systematically explore its electrochemical property as the cathode material for rechargeable aqueous zinc-ion (Zn-ion) batteries. Benefiting from the strong interfacial interaction between VS2 and N-doped carbon, the resulting cathode shows an outstanding specific capacity of 203 mA h g−1 at 50 mA g−1 and displays impressive long-term cycling stability with a capacity retention of 97% after 600 cycles at 1000 mA g−1. The mechanisms involved were clarified by ex situ X-ray diffraction (XRD) measurements. This study provides a new prospect for developing better cathodes for aqueous rechargeable Zn-ion batteries.
45 citations
TL;DR: In this paper, a mesoporous Fe2O3 nanosphere consisting of nanocrystalline subunits is wrapped by Ti3C2Tx MXene, which acting as the shield can effectively mitigate the volume change of γ-Fe2O 3 nanosphere and guarantee a fast electron flow.
38 citations
TL;DR: In this paper, an interesting atom migration phenomenon induced by Kirkendall effect is reported for the preparation of cobalt-iron (Co-Fe) phosphides by the direct phosphorization of Co-Fe alloys.
Abstract: Transition metal phosphides (TMPs), especially the dual-metal TMPs, are highly active non-precious metal oxygen evolution reaction (OER) electrocatalysts. Herein, an interesting atom migration phenomenon induced by Kirkendall effect is reported for the preparation of cobalt-iron (Co-Fe) phosphides by the direct phosphorization of Co-Fe alloys. The compositions and distributions of the Co and Fe phosphides phases on the surfaces of the electrocatalysts can be readily controlled by Cox Fey alloys precursors and the phosphorization process with interesting atom migration phenomenon. The optimized Co7 Fe3 phosphides exhibit a low overpotential of 225 mV at 10 mA cm-2 in 1 m KOH alkaline media, with a small Tafel slope of 37.88 mV dec-1 and excellent durability. It only requires a voltage of 1.56 V to drive the current density of 10 mA cm-2 when used as both anode and cathode for overall water splitting. This work opens a new strategy to controllable preparation of dual-metal TMPs with designed phosphides active sites for enhanced OER and overall water splitting.
32 citations
TL;DR: In this article, γ-Al2O3-supported CuO (c-CuO/Al 2O3) materials were successfully synthesized using a novel impregnation-precipitation-decomposition method, which shows excellent catalytic activities for bisphenol A degradation with sodium persulfate (PDS) as an oxidant.
Abstract: In this work, γ-Al2O3-supported CuO (c-CuO/Al2O3) materials are successfully synthesized using a novel impregnation-precipitation-decomposition method. The obtained c-CuO/Al2O3 catalyst shows excellent catalytic activities for bisphenol A (BPA) degradation with sodium persulfate (PDS) as an oxidant. Radical quenching tests and electron paramagnetic resonance (EPR) studies indicate that PDS activation is a combined mechanism involving both free radical and nonfree radical pathways. In a continuous large-scale degradation process, about 1.78 L of 20 ppm BPA can be completely removed within 480 min. Although c-CuO/Al2O3 can be deactivated after several reaction cycles, the catalytic activity can be regenerated after simple aerobic calcination. X-ray photoelectron spectroscopy (XPS) and Raman analysis confirm that the deactivation of c-CuO/Al2O3 should be attributed to the conversion of Cu(II) to Cu(I). The aerobic calcination could oxidize Cu(I) back to Cu(II), thus recovering the catalytic activity. In addition, the density functional technology (DFT) and temperature-programmed oxidation (TPD) results reveal that γ-Al2O3 can not only serve as a carrier to anchor the CuO particles but also can adsorb and activate PDS by introducing more basic sites on the surface. c-CuO/Al2O3 has high activity and can be regenerated easily, thus having great potential applications for wastewater treatment.
26 citations
TL;DR: This study provides a facile method for metal-free catalyst synthesis, which also enriches the synergistic mechanism between doped N and structural defects and thus should have great potential in wastewater remediation.
25 citations
TL;DR: A nitrogen and sulfur co-doped graphene anchored on the interconnected conductive graphite foam is fabricated via drop-casting and in situ annealing, which significantly enhanced the electrochemical activation of peroxymonosulfate for catalytic oxidation.
25 citations
TL;DR: In this article, cobalt and phosphorus co-doped graphitic carbon nitride (g-C3N4) was synthesized by a facile one-pot pyrolysis method.
Abstract: Peroxydisulfate (PDS) can be activated by graphitic carbon nitride (g-C3N4) under irradiation, and the generated oxygen reactive species (ROSs) can degrade organic pollutants effectively. However, the photocatalytic activity of pristine g-C3N4 is limited due to its narrow light absorption range and rapid electron–hole recombination. Herein, cobalt and phosphorus co-doped g-C3N4 (Co, P-CN) was synthesized by a facile one-pot pyrolysis method. Co and P co-doping enhances the light absorption and charge separation, thus greatly promoting the photocatalytic activation of PDS. Additionally, the presence of doped Co2+ can chemically activate PDS, with Co2+ transforming into Co3+ simultaneously. Recycling tests reveal that Co2+ in Co, P-CN can maintain a high level attributing to the fast Co3+/Co2+ transformation rate under light irradiation. The density functional theory (DFT) calculations show that the Co–Nx species formed by chemical coordination between Co and g-C3N4 in Co, P-CN could effectively activate PDS. The synergistic effect of photo-catalytic and chemical-catalytic driven PDS activation and a faster Co3+/Co2+ redox cycle result in the enhanced bisphenol A (BPA) degradation with a reaction rate constant (k) of 0.375 min−1, which is 7 times larger than that of pristine g-C3N4. This work provides an effective method for the in situ regeneration of active low-valent transition metal ions, and reveals the mechanism of synergistic activation of PDS by photo-catalysis and chemical-catalysis for pollutant degradation.
TL;DR: In this paper, a review summarizes the progress in the synthesis of transition metal carbides or nitrides (MXene) derivatives with different morphologies, including 0D quantum dots, 1D nanoribbons, 2D nanosheets and 3D nanoflowers.
Abstract: Transition metal carbides or nitrides (MXene) have shown promising applications in energy convention and storage (ECS), owing to their high conductivity and adjustable surface functional groups. In the past several years, many MXene derivatives with different structures have been successfully prepared and their impressive performance demonstrated in ECS. This review summarizes the progress in the synthesis of MXene and typical Ti3C2Tx MXene derivatives with different morphologies, including 0D quantum dots, 1D nanoribbons, 2D nanosheets and 3D nanoflowers. The mechanisms involved and their performance in photocatalysis, electrocatalysis and rechargeable batteries are also discussed. Furthermore, the challenges of MXene derivatives in ECS are also proposed.
TL;DR: In this paper, an electrodeposition-calcination-electrodeposition strategy was used to construct the NiMo-O/Ni₄Mo nanointerface on an N-doped carbon support derived from polyaniline on carbon fiber paper.
Abstract: Designing hydrogen evolution reaction catalysts with high performance in alkaline conditions is important for reducing energy consumption during water electrolysis. This study reports an electrodeposition–calcination–electrodeposition strategy to construct the Ni–Mo–O/Ni₄Mo nanointerface on an N-doped carbon support derived from polyaniline on carbon fiber paper. The N-doped carbon support not only stabilizes the metal/metal oxide nanointerface but also generates more active intrinsic sites and electrical conductivity via the metal–N interaction. The obtained Ni–Mo–O/Ni₄Mo@NC displays a low overpotential of only 61 mV at a current density of 10 mA cm–² for alkaline HER in 1 M KOH.
TL;DR: In this paper, a two-dimensional (2D) hierarchical structure of Mn2O3@graphene was constructed to achieve a reversible discharge capacity of 850.3 mA hg−1 at a current density of 300 mA g−1.
Abstract: There has been increasing interest in aqueous Zn-ion batteries (ZIBs) because of their absolute safety, but it remains challenging to develop cathode materials with a high rate capability and cycling stability. Herein, we report a one-step strategy to construct a unique two-dimensional (2D) hierarchical structure of Mn2O3@graphene. Mn2O3 nanosheets are vertically grown on few-layered graphene via a fast one-step molten salts method. Benefiting from the unique 2D hierarchical structure with high electronic and ionic conductivity, as well as the synergetic effect between Mn2O3 and graphene, the Mn2O3@graphene here displays extraordinary electrochemical performance in ZIBs. In particular, it shows a record high reversible discharge capacity of 850.3 mA h g−1 at a current density of 300 mA g−1. Moreover, a high reversible capacity of 125 mA h g−1 after 5000 cycles at a high current density of 7000 mA g−1 (88.8 mA h g−1 at 30 000 mA g−1) can be achieved. These excellent electrochemical performances of Mn2O3@graphene are found to be superior to those of most electrode materials previously reported.
TL;DR: According to the quenching tests, both radical and non-radical processes are present for PMS activation, thus obtaining enhanced organics removal efficiency and the electrochemically assistant could enhance the PMS adsorption on the electrode as well as electrons transfer between Fen+ and PMS, thus increasing thePMS activation efficiency.
TL;DR: In this paper, 3D porous N-doped graphene aerogel catalysts with high activity and selectivity for the C-H bond oxidation under mild reaction conditions have been synthesized through a two-step method.
Abstract: N-doped carbon materials represent a type of metal-free catalyst for diverse organic synthetic reactions. However, single N-doped carbon materials perform insufficiently in the selective oxidation reaction of C-H bond compared with metal catalysts or multielement co-doped materials. There are a few reports on the application of three-dimensional (3D) carbon materials in such a reaction. Besides, the relationship between the well-developed porous structures, heteroatom doping, and their catalytic performance is unclear. In this study, 3D porous N-doped graphene aerogel catalysts with high activity and selectivity for the C-H bond oxidation under mild reaction conditions have been synthesized through a two-step method. Systematic studies on the dosage of N sources, pyrolysis temperature, and their influences on the catalytic performances have been evolved. Moreover, solid evidence of the synergistic effect of sp2 C atoms adjacent to the N atoms and porous structure promoting the performance has been provided in this work.
TL;DR: In this paper, a two-dimensional metallic 1T phase WS2 (1T-WS2) nanosheets modified functional separator is developed to improve the electrochemical performance.
21 Apr 2021
TL;DR: The development of safe and efficient intracellular gene delivery vectors is crucial for successful gene therapy and is needed for the treatment of many diseases.
Abstract: Gene therapy is a revolutionary biomedical technique for the treatment of many diseases, and the development of safe and efficient intracellular gene delivery vectors is crucial for successful gene...
TL;DR: In this paper, the electrochemical mechanism at the cathode of aqueous zinc-manganese batteries (AZMBs) is discussed due to different electrode materials, electrolytes and working conditions.
TL;DR: In this paper, a facile efficient partial etching strategy was proposed to tailor thickness and lateral size of monolayer MoS2 (WS2) nanosheets so as to increase the fraction of edges.
TL;DR: In this paper, a facile atmospheric pressure chemical vapor deposition (CVD) method is used for the synthesis of nitrogen and sulfur co-doped hollow carbon sphere (NSC), which is used as template for the formation of hollow and highly hierarchical porous carbon structure.
TL;DR: In this article, a two-stage method based on Gated Gaseous Hydrogel (GH N−C) was used to synthesize tunable nitrogen configuration for the Hypothesis Oxygen Reduction Reaction (ORR).
TL;DR: In this article, a facile pyrolysis method was used to synthesize an iron oxide (FexOy) supported on porous nitrogen doped carbon, which showed superior catalytic oxidation ability and can activate peroxymonosulfate (PMS) in a wide pH range (3-9).
TL;DR: Ru-pCo@NC as discussed by the authors is a nanoclusters-decorated ruthenium, cobalt nanoparticles, and nitrogen codoped porous carbon catalyst with bimetallic zeolite imidazole frameworks as the precursor.
Abstract: Exploring the economical, powerful, and durable electrocatalysts for hydrogen evolution reaction (HER) is highly required for practical application. Herein, nanoclusters-decorated ruthenium, cobalt nanoparticles, and nitrogen codoped porous carbon (Ru-pCo@NC) are prepared with bimetallic zeolite imidazole frameworks (ZnCo-ZIF) as the precursor. Thus, the prepared Ru-pCo@NC catalyst with a low Ru loading of 3.13 wt% exhibits impressive HER catalytic behavior in 1 M KOH, with an overpotential of only 30 mV at the current density of 10 mA cm−2, Tafel slope as low as 32.1 mV dec−1, and superior stability for long-time running with a commercial 20 wt% Pt/C. The excellent electrocatalytic properties are primarily by virtue of the highly specific surface area and porosity of carbon support, uniformly dispersed Ru active species, and rapid reaction kinetics of the interaction between Ru and O.