Harnessing Visible Light for CO2 Conversion: The Role of Highly Reduced Phosphomolybdate Crystals as Powerful Photocatalysts

Inorg Chem. 2024 Nov 4;63(44):21303-21312. doi: 10.1021/acs.inorgchem.4c03810. Epub 2024 Oct 25.

Abstract

Heterogeneous photocatalysts, characterized by well-defined atomic structures and the capacity for rapid, directional electron transfer, are pivotal in the exploration and development of highly efficient systems for visible-light-driven diluted CO2 reduction. Herein, we constructed highly reduced phosphomolybdates crystalline materials 1-3 to help this process, with the formula of [Co2(C8N3H7)4][Co2(C8N3H7)4(H2O)2][Co(H7P4Mo6O31)2]·8H2O (1), [Ni2(C8N3H7)4(H2O)2][Ni2(C8N3H7)4][Ni(H2O)4][Ni(H6P4Mo6O31)2]·3H2O·2C2H5OH (2), and [Zn2(C8N3H7)2][Zn2(C8N3H7)4][Zn2(C8N3H7)2(H2O)2][Zn(H5P4Mo6O31)2] (3) [C8N3H7 = 2-(1H-pyrazol-3-yl)pyridine]. Specifically, catalyst 1 demonstrated a CO production rate of 3276.4 μmol g-1 h-1 in an environment with 20% CO2 concentration, and an impressively elevated rate of 10740.3 μmol g-1 h-1 in a pure CO2 atmosphere. Steady-state photoluminescence spectroscopy revealed that the directional migration of photoelectrons from the Ru complexes to the catalyst was instrumental in enhancing the catalytic activity. This study provides valuable insights into the rational operation of low-concentration CO2 conversion treatment and the design and synthesis of photocatalysts.