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

Kanemichi Muraoka (1, 2) , Miharu Eguchi (3) , Osamu Ishitani (1) , François Cheviré (4) , Kazuhiko Maeda (1)

1 TITECH - Tokyo Institute of Technology [Tokyo]
2 Japanese Society for the Promotion of Science Fellow
3 NIMS - National Institute for Materials Science
4 ISCR - Institut des Sciences Chimiques de Rennes

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_xN_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_xN_y examined, TbTaO_xN_y gave the highest performance for CO₂ reduction under visible light (λ > 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_xN_y with the absence of Ln-4f states in the band gap structure contributed to higher activity of the hybrid photocatalyst.

Keywords: Artificial photosynthesis; Heterogeneous photocatalysis; Mixed anion compounds; Solar fuels

Domains: Chemical Sciences; Chemical Sciences; Material chemistry

Kanemichi Muraoka, Miharu Eguchi, Osamu Ishitani, François Cheviré, Kazuhiko Maeda. Selective CO₂ reduction into formate using Ln-Ta oxynitrides combined with a binuclear Ru(II) complex under visible light. Journal of Energy Chemistry, 2021, 55, pp.176-182. ⟨10.1016/j.jechem.2020.06.064⟩. ⟨hal-02895318⟩