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.
Keywords: CO2 photoreduction; amorphous nanosheets; hetero-anionic coordination; oxygen defects; symmetry breaking.
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