Harnessing\nVisible Light for CO<sub>2</sub> Conversion:\nThe Role of Highly Reduced Phosphomolybdate Crystals as Powerful Photocatalysts

Heterogeneous photocatalysts, characterized by well-defined\natomic\nstructures and the capacity for rapid, directional electron transfer,\nare pivotal in the exploration and development of highly efficient\nsystems for visible-light-driven diluted CO<sub>2</sub> reduction.\nHerein, we constructed highly reduced phosphomolybdates crystalline\nmaterials <b>1</b>–<b>3</b> to help this process,\nwith the formula of [Co<sub>2</sub>(C<sub>8</sub>N<sub>3</sub>H<sub>7</sub>)<sub>4</sub>]​[Co<sub>2</sub>(C<sub>8</sub>N<sub>3</sub>H<sub>7</sub>)<sub>4</sub>(H<sub>2</sub>O)<sub>2</sub>]​[Co(H<sub>7</sub>P<sub>4</sub>Mo<sub>6</sub>O<sub>31</sub>)<sub>2</sub>]·8H<sub>2</sub>O (<b>1</b>), [Ni<sub>2</sub>(C<sub>8</sub>N<sub>3</sub>H<sub>7</sub>)<sub>4</sub>(H<sub>2</sub>O)<sub>2</sub>]​[Ni<sub>2</sub>(C<sub>8</sub>N<sub>3</sub>H<sub>7</sub>)<sub>4</sub>]​[Ni(H<sub>2</sub>O)<sub>4</sub>]​[Ni(H<sub>6</sub>P<sub>4</sub>Mo<sub>6</sub>O<sub>31</sub>)<sub>2</sub>]·3H<sub>2</sub>O·2C<sub>2</sub>H<sub>5</sub>OH (<b>2</b>), and [Zn<sub>2</sub>(C<sub>8</sub>N<sub>3</sub>H<sub>7</sub>)<sub>2</sub>]​[Zn<sub>2</sub>(C<sub>8</sub>N<sub>3</sub>H<sub>7</sub>)<sub>4</sub>]​[Zn<sub>2</sub>(C<sub>8</sub>N<sub>3</sub>H<sub>7</sub>)<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]​[Zn(H<sub>5</sub>P<sub>4</sub>Mo<sub>6</sub>O<sub>31</sub>)<sub>2</sub>] (<b>3</b>) [C<sub>8</sub>N<sub>3</sub>H<sub>7</sub> = 2-(1H-pyrazol-3-yl)pyridine]. Specifically,\ncatalyst <b>1</b> demonstrated a CO production rate of 3276.4\nμmol g<sup>–1</sup> h<sup>–1</sup> in an environment\nwith 20% CO<sub>2</sub> concentration, and an impressively elevated\nrate of 10740.3 μmol g<sup>–1</sup> h<sup>–1</sup> in a pure CO<sub>2</sub> atmosphere. Steady-state photoluminescence\nspectroscopy revealed that the directional migration of photoelectrons\nfrom the Ru complexes to the catalyst was instrumental in enhancing\nthe catalytic activity. This study provides valuable insights into\nthe rational operation of low-concentration CO<sub>2</sub> conversion\ntreatment and the design and synthesis of photocatalysts.