Solar Water Splitting under Neutral Conditions Using Z‐Scheme Systems with Mo‐Doped BiVO₄ as an O₂‐Evolving Photocatalyst

Abstract

The photocatalytic water‐splitting system ideally consists of just photocatalyst powder and water without any additives. Herein, improvement of water‐splitting activity under neutral conditions is achieved by applying Mo‐doping and cocatalyst‐loading to BiVO4 of an O2‐evolving photocatalyst in a Z‐scheme system with Ru‐loaded SrTiO3 doped with Rh as a H2‐evolving photocatalyst and a reduced graphene oxide as an electron mediator. The strategies are based on the idea that the Z‐schematic electron migration process in the powdered Z‐scheme system with reduced graphene oxide is similar to that in the photoelectrochemical system. Although the reaction condition becomes out of the ideal states, adding Ca(NO3)2 and CaCl2 into the reactant solution further improves the water‐splitting activity due to the formation of aggregated photocatalyst particles to boost the electron transfer from Mo‐doped BiVO4 to Ru‐loaded SrTiO3 doped with Rh through the reduced graphene oxide.

A Macroporous-Structured WO3/Mo-Doped BiVO4 Photoanode for Vapor-Fed Water Splitting under Visible Light Irradiation

“…Bismuth vanadate (BiVO 4 ) is a potential oxide photocatalyst and photoanode working under visible light irradiation because of the narrow bandgap (∼2.4 eV) of the monoclinic scheelite structure. − However, the quantum efficiency is limited by the low electrical conductivity, low hole transfer efficiency, and the fast recombination of photogenerated electrons and holes. The strategies of heterojunction formation and donor doping have been addressed to resolve these issues.…”

Examination of photocatalytic Z-scheme system for overall water splitting with its electronic structure

“…17 Meanwhile, the average diameters of SrTiO 3 :Rh,La and BiVO 4 :Mo particles had been determined by SEM as 0.3-0.7 mm and 0.5-2 mm, respectively. 17,34 As a reference, the observed values of the specific surface area of SrTiO 3 :Rh and BiVO 4 particles, prepared according to the abovementioned synthetic processes, had been determined by BET as 2.6 m 2 g À1 and 1.8 m 2 g À1 , respectively, [35][36][37] suggesting that SrTiO 3 :Rh,La and BiVO 4 :Mo particles prepared in this study had similar values of specific surface area. The X-ray diffraction patterns for SrTiO 3 :Rh,La and BiVO 4 :Mo particles could be assigned to perovskite-type SrTiO 3 with cubic phase and seelite-type BiVO 4 with monoclinic phase, respectively (Fig.…”

Review on the preparation and performance improvement methods of bismuth photocatalyst materials

“…98 Catalysis Science & Technology Mini review Molybdenum and tungsten have thus been used frequently as efficient dopants for BiVO 4 . 99 As Regmi et al demonstrated, 100 copper is also used as a dopant for BiVO 4 . They used microwave-assisted hydrothermal synthesis to make Cu-doped BiVO 4 and found that it had higher photocatalytic activity than undoped BiVO 4 for degrading ibuprofen and methylene blue while inactivating Escherichia coli.…”