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

H ₂ O dissociation plays a crucial role in solar-driven catalytic CO ₂ methanation, demanding high temperature even for solar-to-chemical conversion efficiencies <1% with modest product selectivity. Herein, we report an oxygen-vacancy (V _o ) rich CeO ₂ catalyst with single-atom Ni anchored around its surface V _o sites by replacing Ce atoms to promote H ₂ O dissociation and achieve effective photothermal CO ₂ reduction under concentrated light irradiation. The high photon flux reduces the apparent activation energy for CH ₄ production and prevents V _o 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 ₂ O activation. The catalyst presents a CH ₄ yield of 192.75 µmol/cm ² /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 ₂ O-activating catalysts for CO ₂ reduction and thereby expedite the practical utilization of solar-to-chemical technologies.
(© 2024. The Author(s).)