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

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 LnTaO(x)N(y) (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 LnTaO(x)N(y) examined, TbTaOxNy gave the highest performance for CO2 reduction under visible light (lambda > 400 nm), with a RuRu'-based turnover number of 18 and high selectivity to formate (>99%). Physicochemical analyses indicated that high crystallinity and more negative conduction band potential of LnTaO(x)N(y) with the absence of Ln-4f states in the band gap structure contributed to higher activity of the hybrid photocatalyst. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

Hybrid materials constructed from defect fluorite-type Ln-Ta oxynitrides as the semiconductor component, combined with known Ag nanoparticle promoter and binuclear ruthenium(II) complex, have demonstrated efficient photocatalytic performance for CO2 reduction under visible light. Among the LnTaO(x)N(y) examined, TbTaOxNy showed the highest activity and selectivity towards formate under visible light conditions.