Surface Oxygen Vacancy-Dependent Electrocatalytic Activity of W₁₈O₄₉ Nanowires

Abstract

Surface oxygen vacancies (SOVs) are the most relevant surface defects in metal oxides (MOs), and they participate in numerous physical and chemical reactions. However, information on the nature, distribution, formation, and reactivity of SOVs, as well as relationships among SOVs, is lacking. Investigating SOVs is difficult because of disturbance by the crystal phase, morphology of bulk materials, and synergistic effect between substrate and catalyst host. Herein, by clarifying the origin of SOVs and their distribution, onedimensional (1D) tungsten oxide nanowires (NWs) with numerous SOVs were synthesized. Compared with the three-dimensional nanostructure, the high aspect ratio of 1D NW exposed the SOVs on the surface of the nanostructure rather than embedding them in the bulk. To investigate accurately the effect of SOVs on electrocatalytic activity, we clearly identified how SOVs of tungsten oxide catalyst regulate iodide reduction reactions in the solar cell by in situ filling of SOVs in electrodes and maintaining the crystal phase and morphology of NWs. Iodide reduction reaction activity was notably dependent on tungsten oxide catalyst SOVs, which serve as important catalytic site descriptors. These findings may clarify the fundamental features of SOVs on metal oxides and contribute to the rational design of efficient catalysts and supports.

Fibrous silica mesoporous ZSM-5 for carbon monoxide methanation

“…Song et al reported a linear dependence between the hydrogenation activity and oxygen vacancy concentration in oxygen-deficient tungsten oxide catalysts[40]. Moreover, Zhou et al reported the surface oxygen vacancy-dependent electrocatalytic activity of tungsten oxide nanowires, in which these surface oxygen vacancy served as catalytic site descriptors[41]. In addition, Zhang et al studied the relation of surface defects (surface oxygen vacancies or defects) with the photocatalytic activity[42].…”

A composite catalyst of reduced black TiO2−x/CNT: a highly efficient counter electrode for ZnO-based dye-sensitized solar cells

“…Reduced black TiO 2 (TiO 2-x ) with oxygen vacancies (OVs) has been demonstrated to exhibit visible light absorption. [17][18][19][20][21][22][23][24][25][26][27] However, as a counter electrode, the study on reduced black TiO 2 has not been reported in the literature. Black TiO 2-x is prepared via several methods, including heating under reducing conditions (e.g., H 2 ) or vacuum, high-energy particle (electron, laser, or Ar + ) bombardment, and chemical vapor deposition.…”

An Intrinsically Conductive Phosphorus‐Doped Perovskite Oxide as a New Cathode for High‐Performance Dye‐Sensitized Solar Cells by Providing Internal Conducting Pathways

“…The P doping was also evidenced by the P 2s X‐ray photoelectron spectroscopy (XPS) spectra of SC and SCP as shown in Figure a. It was reported that oxygen vacancies and low valence states of metal in metal oxides play important roles in catalyzing IRR . As shown in Figure b, a large oxygen nonstoichiometry was observed for SC, whereas the B‐site doping by elements with high valence states led to a decrease in the oxygen vacancy concentration, especially for the Nb‐doped one due to the larger doping amount.…”