Multifunctional ternary hydrotalcite-like nanosheet arrays as an efficient co-catalyst for vastly improved water splitting performance on bismuth vanadate photoanode

Abstract

A novel ternary hydrotalcite-like nanosheet is directly integrated onto bismuth vanadate (BiVO4) photoanode via a fast, precisely controllable and economic electrodeposition method. The CoMnZn-containing hydroxides could play multifunctional roles as an efficient cocatalyst to lower the onset potential and enhance the photocurrent and as a protection layer for bismuth vandate. The hybrid photoanode shows a much improved PEC performance compared with bare bismuth vanadate, with a photocurrent density enhancement of 170% (from 0.61 mA cm−2 to 1.06 mA cm−2) and a decrease of 280 mV in onset potential. Surface modification of photoanodes with trimetallic hydroxides not only provides more active sites but also greatly improves the migration of holes from bismuth vanadate to LDH. This facilitates the fast separation and transport of holes, thus retarded the recombination of photogenerated charges. In addition, the synergistic effect of transition metals in LDH plays an important role in the enhancement of PEC water oxidation of the hybrid photoanodes. New water oxidation catalyst introduced in this work hold a great promise to be extended to other photoanodes for advanced performance in the fields of energy conversion.