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Solar-powered volatile organic compound oxidation attracts interest, but its efficiency suffers from poor utilization of photogenerated electrons. Oxygen can capture the electrons and convert them into superoxide radicals upon being activated. As a unique oxygen-deficiency oxide, WO2 chemisorbs and activates oxygen and functions as a potential cocatalyst for improving the utilization of charge carriers. Here, we report a WO2/SnS2 composite photocatalyst with SnS2 nanosheets vertically growing out of WO2 nanofibers. In situ X-ray photoelectron spectroscopy and density functional theory calculations suggest the electron transfer from WO2 to SnS2, creating an internal electric field (IEF) at the interfaces with a direction pointing from WO2 to SnS2. The IEF promotes spatial charge separation by driving photogenerated electrons in SnS2 to move to WO2, while photogenerated holes remain immobile. WO2 shows a strong affinity for oxygen-containing species and chemisorbs O2 and H2O molecules in a dissociative way, significantly reducing the kinetic barriers for the production of reactive oxygen species (•OH and •O2–). Under visible light irradiation, the WS30 nanofibers exhibit enhanced photocatalytic degradation of HCHO and CH3COCH3, 4.8 and 7.2 times greater than that of pristine SnS2, respectively. The enhanced performance is attributed to the one-dimensional fibrous nanostructures, robust chemisorption of reactants, and IEF-driven charge separation. This work may inspire efforts to develop higher oxygen-affinity photocatalysts for photodegradation. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation technology can mineralize hazardous volatile organic compounds (VOCs), but the poor photocatalytic oxidation activity limits its practical application. Here we develop Cu‐doped WO3 electrospun nanofibers through a non‐equivalent doping strategy. The Cu dopant prefers substituting five‐coordinated W atoms atop the WO3 matrix, inducing strong dopant/matrix interaction (SDMI) effect and prominent charge rearrangement. A localized electric field (LEF) forms pointing from positively charged WO3 matrix to negatively charged Cu dopant, which triggers efficient photoexcited charge separation. Further, the Cu dopant promoted the production of ⋅OH radicals and thereby enhanced VOCs photodegradation. The 0.7 % Cu‐doped WO3 nanofibers show optimal photocatalytic oxidation performance towards formaldehyde and acetone, 5.5 and 4.8 times higher than pristine WO3 nanofibers, respectively. This work highlights the role of dopant‐induced LEF on the charge carriers separation and might shed light on developing more efficient photocatalysts with non‐equivalent dopants. [ABSTRACT FROM AUTHOR]

Chitosan-based carbon materials have attracted great attention in electrochemical energy storage. Introducing iron metal or iron compounds into carbon materials favors to boost their electrochemical performance. Herein, chitosan-based graphitic carbon@Fe3C composites (CSGC@Fe3C) have been prepared as anode materials for lithium ion battery by a simple pyrolysis method. By manipulating the temperature higher than 700 °C, pure Fe3C encapsulated in chitosan-based graphitic carbon with different mass ratio from 30 to 53.8 wt% can be achieved. The resulting CSGC@Fe3C composites retain porous carbon sheet structure embedded with a large amount of Fe3C nanoparticles in size from 20 to 300 nm. The electrochemical measurements demonstrate CSGC@Fe3C with 53.8 wt% Fe3C as anode material for lithium ion battery can provide a highest reversible capacity of 423 mAh g−1 at 0.1 A g−1 over 100 charge/discharge cycles and stable cycling capacity of 195 mAh g−1 at a high current density of 2 A g−1 during 200 cycles. The catalysis of Fe3C on the reversible formation and decomposition of solid electrolyte interphase (SEI) has been corroborated and results in the improvement of surface capacitive contribution. This work provides a basic insight into metal carbides constructing biomass-based carbon anode materials to realize high-performance electrochemical energy storage device. [ABSTRACT FROM AUTHOR]