Tuning the Electronic Structure of Monoclinic Tungsten Oxide Nanoblocks by Indium Doping for Boosted Photoelectrochemical Performance

Abstract

Photoelectrochemical (PEC) water oxidation, a desirable strategy to meet future energy demands, has several bottlenecks to resolve. One of the prominent issues is the availability of charge carriers at the surface reaction site to promote water oxidation. Of the several approaches, metal dopants to enhance the carrier density of the semiconductors, is an important one. In this work, we have studied the effect of In-doping on monoclinic WO 3 nanoblocks, growing vertically over fluorine-doped tin oxide (FTO) without the aid of any seed layer. X-ray photoelectron spectroscopy (XPS) data reveals that In 3 + ions are partially occupying the W 6 + ions in In-doped WO 3 photoanode. In 3 + ions are offering better performance by adding additional charge carriers for amplifying the expression of the number of carriers. The maximum current density value of 2.18 mA/cm 2 has been provided by the optimized In-doped WO 3 photoanode with 3 wt% indium doping at 1.23 V vs. RHE, which is~3 times higher than that of undoped monoclinic WO 3 photoanode. Mott-Schottky (MS) analysis reveals charge carrier density (N D) for In-doped WO 3 photoanode has been enhanced by a factor of 3. An average Faradic yield of~90 percent has been achieved which can serve as a model system using In 3 + as a dopant for an inexpensive and attractive method for enhanced WO 3 based PEC water oxidation.

In/Ce Co-doped Li3VO4 and Nitrogen-modified Carbon Nanofiber Composites as Advanced Anode Materials for Lithium-ion Batteries

“…35,54 The two peaks at 444.19 and 451.73 eV in the high-resolution spectrum of In 3d (Figure 2e) can be assigned to the spin−orbit levels of In 3d 5/2 and In 3d 3/2 , respectively, indicating the presence of In 3+ . 55,56 The XPS high-resolution spectrum of Ce 3d in Figure 2f displays two peaks at 881.83 and 901.33 eV, indicating the presence of Ce 4+.57−59 2.2. Electronic Properties of In/Ce Co-doping.…”

“…In addition, in order to maintain charge balance, the presence of V 4+ means that O 2– in the system loses electrons and form O 2 , followed by the release from the lattice (V 5+ + e – → V 4+ , 1/2O 2– – e – → 1/2O 2 ↑), resulting in the generation of oxygen defects, as shown in the O 1s spectrum (Figure d). In the high-resolution spectrum of O1s, the two peaks located at 530.11 and 531.99 eV can be ascribed to O 2– and oxygen defects. , The oxygen defects combined with the extrinsic defects derived from N-modified carbon provide more active sites for enhancing the adsorption of cations, promoting rapid ion and electron transportation and producing a significant capacitive effect. , The two peaks at 444.19 and 451.73 eV in the high-resolution spectrum of In 3d (Figure e) can be assigned to the spin–orbit levels of In 3d 5/2 and In 3d 3/2 , respectively, indicating the presence of In 3+ . , The XPS high-resolution spectrum of Ce 3d in Figure f displays two peaks at 881.83 and 901.33 eV, indicating the presence of Ce 4+. − …”

Influence of the Solvent Used for Microwave‐Assisted Synthesis of W−BiVO4 on Properties and Photoelectroactivity of W−BiVO4/WO3

“…Mohanta and co-workers, for instance, prepared nanostructured WO 3 films onto FTO glass under the conventional hydrothermal method and reported photocurrents of 0.71 mA cm À 2 at ~1.2 V vs. RHE using 0.1 M Na 2 SO 4 aqueous solution at pH 6 as electrolyte. [73] Soltani and co-workers reported the synthesis of plate-like WO 3 from the hydrothermal treatment of tungsten foils in oxidizing media. The resulting photocurrent was 4.12 mA cm À 2 at 1.6 V vs. Ag/AgCl in neutral media.…”

Surface charge-directed borophene–phosphorous nitride nanodot heterojunction supports for enhanced photoelectrochemical performance

“…10–12 These limitations can be solved by surface engineering, metal and nonmetal doping, heterojunctions, quantum dot modification, overlayer and co-catalyst incorporation to achieve desirable PEC high water oxidation performance. 13–17…”

“…[10][11][12] These limitations can be solved by surface engineering, metal and nonmetal doping, heterojunctions, quantum dot modification, overlayer and cocatalyst incorporation to achieve desirable PEC high water oxidation performance. [13][14][15][16][17] In recent times, the incorporation of non-metal-based quantum dots (QDs) into PEC photoanodes has been widely explored for their faster charge transfer and better light harvesting behaviour. Zheng et al have achieved faster charge separation and transportation by the incorporation of black phosphorus QDs on the TiO 2 surface.…”