Oxygen Vacancy-Rich S-Scheme CeO<sub>2</sub>@Ni<sub>1–<i>x</i></sub>Co<sub><i>x</i></sub>Se<sub>2</sub> Hollow Spheres Derived from NiCo-MOF for Remarkable Photocatalytic CO<sub>2</sub> Conversion
Wei Han, Yajie Chen, Yuzhen Jiao, Shumei Liang, Wei Li, Guohui Tian
Abstract
Photocatalytic CO 2 conversion into chemicals has been a promising strategy to utilize sustainable solar energy and alleviate the greenhouse effect. Nonetheless, the achievements of these photocatalytic reactions are challenging. Herein, we present a strategy for the synthesis of hierarchical CeO 2 @Ni 1– x Co x Se 2 hollow spheres (HSs) including the successive steps of coating of the CeO 2 nanolayer on SiO 2 spheres, in situ growth of NiCo-MOF nanosheets, selenization reaction, and subsequent etching treatment. The hierarchical CeO 2 @Ni 1– x Co x Se 2 HSs exhibiting intimate interface contact between two nanoshells form an S-scheme heterojunction with fast charge/mass transport and excellent visible-light absorption, while maintaining the strong reducing power of electrons in the conduction band of Ni 1– x Co x Se 2 nanosheets and the strong oxidizing capacity of holes in the valence band of CeO 2 HSs with oxygen vacancies. The S-scheme photogenerated charge transfer mechanism was testified by the work function and electron paramagnetic resonance measurements. These advantages make the optimized CeO 2 @Ni 1– x Co x Se 2 HS sample exhibit superior activity and high stability in photocatalytic CO 2 reduction with a CO production rate of 25.93 μmol h –1 g –1 . This work provides more opportunities to fabricate other hierarchical S-scheme semiconductor-based photocatalysts.