Tunable C<sub>2</sub> Products via Photothermal Steam Reforming of CO<sub>2</sub> over Surface-Modulated Mesoporous Cobalt Oxides.

Xiong, Yan; Zhao, Wanghui; Gu, Dong; Tie, Zuoxiu; Zhang, Wenhua; Jin, Zhong · Nano Lett · 2023

basic_science · Level V

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Abstract

The conversion of CO<sub>2</sub> to high-value products by renewable energy is a promising approach for realizing carbon neutralization, but the selectivity and efficiency of C<sub>2+</sub> products are not satisfying. Herein, we report the controllable preparation of highly ordered mesoporous cobalt oxides with modulated surface states to achieve efficient photothermal water-steam reforming of CO<sub>2</sub> to C<sub>2</sub> products with high activity and tunable selectivity. Pristine mesoporous Co<sub>3</sub>O<sub>4</sub> exhibited an acetic acid selectivity of 96% with a yield rate of 73.44 μmol g<sup>-1</sup> h<sup>-1</sup>. By rationally modifying mesoporous Co<sub>3</sub>O<sub>4</sub> surface states, mesoporous Co<sub>3</sub>O<sub>4</sub>@CoO delivered a radically altered ∼100% ethanol selectivity with a yield rate of 14.85 μmol g<sup>-1</sup> h<sup>-1</sup>. Comprehensive experiments revealed that the pH value could strongly influence the selectivity of C<sub>2</sub> products over mesoporous cobalt oxides. Density functional theory verified that reduced surface states and rich oxygen vacancies on surface-modified mesoporous cobalt oxides could facilitate further variation of C<sub>2</sub> products from acetic acid to ethanol.