Mass-transfer control for selective deposition of well-dispersed AuPd cocatalysts to boost photocatalytic H2O2 production of BiVO4

Abstract

Owing to excellent activity and selectivity for two-electron O2 reduction to H2O2, well-dispersed AuPd nanoalloy cocatalyst is high desired for photocatalytic H2O2 production. In practice, however, it is hardly realized due to technical difficulty. Utilizing the directed transfer of photocarriers in BiVO4 single crystal with crystal-facet exposure, in this work, a mass-transfer control approach is developed for selective photodeposition of well-dispersed AuPd cocatalysts to boost photocatalytic H2O2 production. The as-obtained BiVO4 (010)-AuPd photocatalysts exhibit improved photocatalytic activity for H2O2 production compared with BiVO4 (010)-Au (1.15 mmol L−1) and BiVO4 (010)-Pd (1.37 mmol L−1). Therein, the optimum BiVO4 (010)-AuPd photocatalyst (the mass ratio of Au to Pd for 19:1) presents the highest H2O2 production (2.29 mmol L−1 in 2 h under 420 nm light irradiation) and the corresponding AQE value is 11.38 %. In the case, the synergistic effect of electronic effects and geometric effects for the well-dispersed AuPd nanoalloy cocatalysts contribute to excellent activity and selectivity for two-electron O2 reduction to H2O2 and thus boost the photocatalytic H2O2 production of BiVO4. The present work also provides an insight into the modification of well-dispersed nanoalloy cocatalysts for photocatalytic H2O2 production.