Selective Photocatalytic Conversion of CO<sub>2</sub> to Ethanol via Unsaturated Cu-O Domains.

Wang, Qiang; He, Mingqi; Yang, Pengxin; Zhou, Yanan; Wang, Xing; Zhang, Kaifu; Jiang, Zhuo; Luo, Qiquan et al. · ACS Nano · 2024

basic_science · Level V

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Abstract

Enhancing the selectivity of photocatalytic CO<sub>2</sub> reduction to valuable multicarbon (C<sub>2+</sub>) products remains a significant challenge in green synthetic chemistry. Here, we present a dual-center strategy for metal oxides that boosts the photochemical conversion of CO<sub>2</sub> to ethanol by regulating the coordination number of metal and oxygen sites. Notably, CuO catalysts rich in low-coordinated Cu-O domains have achieved nearly perfect ethanol selectivity (96.9%), extraordinary durability (60 h), and a superior yield rate of 30.5 μmol·g<sup>-1</sup>·h<sup>-1</sup>, surpassing the performance of many existing photocatalysts in water vapor and CO<sub>2</sub>. Density functional theory calculations and operando spectroscopic results provide conclusive evidence that tricoordinated copper (Cu<sub>3c</sub>) increases the coverage of key *CO species, while bicoordinated oxygen (O<sub>2c</sub>) controls the migration of *CO species, thereby effectively reducing the energy requirement for *CO dimerization into *OC-CO intermediates (Δ<i>G</i><sub><i>*</i>OC-CO</sub> = -0.56 eV) in the ethanol pathway. This work offers valuable insights for designing photocatalysts that exhibit improved selectivity for C<sub>2+</sub> fuels.