Red light-inducible overall water-splitting photocatalyst, gold-inserted zinc rhodium oxide and bismuth vanadium oxide heterojunction, connected using gold prepared by sputtering in ionic liquid

Abstract

We prepared a solid-state Z-scheme photocatalyst in which zinc rhodium oxide (ZnRh₂O₄) and bismuth vanadium oxide (Bi₄V₂O₁₁) that served as hydrogen (H₂) and oxygen (O₂) evolution photocatalysts, respectively, were connected with gold (Au) nanoparticles. The Au nanoparticles were prepared by sputtering in an ionic liquid, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide, to generate Au/ZnRh₂O₄/Au/Bi₄V₂O₁₁ with various amounts of Au in the 12 mol. %-29 mol. % range (vs 1.0 mol ZnRh₂O₄ + 0.2 mol Bi₄V₂O₁₁). Au/ZnRh₂O₄/Au/Bi₄V₂O₁₁ photocatalyzed overall pure-water splitting under irradiation with red light at a wavelength of 700 nm, and the dependence of the amounts of Au on the apparent quantum efficiency tended to increase in the measurement range.