Symmetry Breaking Induced Amorphization of Cobalt-Based Catalyst for Boosted CO₂ Photoreduction.

Abstract

Photocatalytic reduction of CO₂ to energy carriers is intriguing in the industry but kinetically hard to fulfil due to the lack of rationally designed catalysts. A promising way to improve the efficiency and selectivity of such reduction is to break the structural symmetry of catalysts by manipulating coordination. Here, inspired by analogous CoO₆ and CoSe₆ octahedral structural motifs of the Co(OH)₂ and CoSe, a hetero-anionic coordination strategy is proposed to construct a symmetry-breaking photocatalyst prototype of oxygen-deficient Se-doped cobalt hydroxide upon first-principles calculations. Such involvement of large-size Se atoms in CoO₆ octahedral frameworks experimentally lead to the switching of semiconductor type of cobalt hydroxide from p to n, generation of oxygen defects, and amorphization. The resultant oxygen-deficient Se,O-coordinated Co-based amorphous nanosheets exhibit impressive photocatalytic performance of CO₂ to CO with a generation rate of 60.7 µmol g^-1 h^-1 in the absence of photosensitizer and scavenger, superior to most of the Co-based photocatalysts. This work establishes a correlation between the symmetry-breaking of catalytic sites and CO₂ photoreduction performances, opening up a new paradigm in the design of amorphous photocatalysts for CO₂ reduction.