Concentrated solar CO<sub>2</sub> reduction in H<sub>2</sub>O vapour with >1% energy conversion efficiency.

Ren, Yuqi; Fu, Yiwei; Li, Naixu; You, Changjun; Huang, Jie; Huang, Kai; Sun, Zhenkun; Zhou, Jiancheng et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

H<sub>2</sub>O dissociation plays a crucial role in solar-driven catalytic CO<sub>2</sub> methanation, demanding high temperature even for solar-to-chemical conversion efficiencies <1% with modest product selectivity. Herein, we report an oxygen-vacancy (V<sub>o</sub>) rich CeO<sub>2</sub> catalyst with single-atom Ni anchored around its surface V<sub>o</sub> sites by replacing Ce atoms to promote H<sub>2</sub>O dissociation and achieve effective photothermal CO<sub>2</sub> reduction under concentrated light irradiation. The high photon flux reduces the apparent activation energy for CH<sub>4</sub> production and prevents V<sub>o</sub> from depletion. The defects coordinated with single-atom Ni, significantly promote the capture of charges and local phonons at the Ni d-impurity orbitals, thereby inducing more effective H<sub>2</sub>O activation. The catalyst presents a CH<sub>4</sub> yield of 192.75 µmol/cm<sup>2</sup>/h, with a solar-to-chemical efficiency of 1.14% and a selectivity ~100%. The mechanistic insights uncovered in this study should help further the development of H<sub>2</sub>O-activating catalysts for CO<sub>2</sub> reduction and thereby expedite the practical utilization of solar-to-chemical technologies.