Self-activated Rh-Zr mixed oxide as a nonhazardous cocatalyst for photocatalytic hydrogen evolution
T. NIshino, M. Saruyama, Z. Li, Y. Nagatsuma, M. Nakabayashi, N. Shibata, T. Yamada, R. Takahata, S. Yamazoe, T. Hisatomi, K. Domen, T. Teranishi
Chem. Sci. 11, 6862-6867 (2020).
Efficient, robust and environmentally friendly cocatalysts for photocatalysts are important for large-scale solar hydrogen production. Herein, we demonstrate that a Rh-Zr mixed oxide is an efficient cocatalyst for hydrogen evolution. Impregnation of Zr and Rh precursors (Zr/Rh = 5 wt/wt%) formed RhZrOx cocatalyst particles on Al-doped SrTiO3, which exhibited 31× higher photocatalytic water-splitting activity than a RhOx cocatalyst. X-ray photoelectron spectroscopy proved that the dissociation of Cl− ions from preformed Rh-Cl-Zr-O solid led to formation of the active phase of RhZrOx, in which the Zr/Rh ratio was critical to high catalytic activity. Additional CoOx loading as an oxygen evolution cocatalyst further improved the activity by 120%, resulting in an apparent quantum yield of 33 (±4)% at 365 nm and a long durability of 60 h. Our discovery could help scale up photocatalytic hydrogen production.