Selective CO2 reduction into formate using Ln–Ta oxynitrides combined with a binuclear Ru(Ⅱ) complex under visible light

作者：Kanemichi Muraoka; Miharu Eguchi; Osamu Ishitani^*; Franois Cheviré; Kazuhiko Maeda^*

来源：Journal of Energy Chemistry, 2021, 55(04): 176-182.

Hybrid materials constructed from a visible-light-absorbing semiconductor and a functional metal complex have attracted attention as efficient photocatalysts for CO2 reduction with high selectivity to a desired product. In this work, defect fluorite-type Ln–Ta oxynitrides LnTaOxNy(Ln = Nd, Sm, Gd, Tb, Dy and Ho) were examined as the semiconductor component in a hybrid photocatalyst system combined with known Ag nanoparticle promoter and binuclear ruthenium(Ⅱ) complex(RuRu’). Among the LnTaOxNy examined, TbTaOxNy gave the highest performance for CO2 reduction under visible light(k > 400 nm), with a Ru Ru0-based turnover number of 18 and high selectivity to formate(>99%).Physicochemical analyses indicated that high crystallinity and more negative conduction band potential of Ln Ta OxNywith the absence of Ln-4 f states in the band gap structure contributed to higher activity of the hybrid photocatalyst.