Modulation of oxygen vacancies and hot electrons promotes highly efficient CO <sub>2</sub> photoreduction towards C <sub>2</sub>H <sub>6</sub>
Chengyang Zhu, Hengming Huang, Huiling Hu, Jiaojiao Fang, Junjie Mao
Abstract
Efficient CO<sub>2</sub> photoreduction towards C<sub>2+</sub> solar fuels has emerged as one of the most promising strategies for alleviating the current energy and environment problems. However, the C-C coupling barriers and complex multi-electron transfer steps still limit the activity and selectivity of CO<sub>2</sub>-to-C<sub>2</sub> photoreduction. Herein, Au nanoparticles (NPs) modified CeO<sub>2</sub> with oxygen vacancies (Au/CeO<sub>2</sub>-V<sub>O</sub>) were reported for enhancing the CO<sub>2</sub>-to-C<sub>2</sub>H<sub>6</sub> photoreduction performance. Au/CeO<sub>2</sub>-V<sub>O</sub> achieved the high C<sub>2</sub>H<sub>6</sub> activity of 51.7 μmol·g<sup>−1</sup>·h<sup>−1</sup>, accompanied with C<sub>2</sub>H<sub>6</sub> selectivity up to 80% in the absence of sacrificial agent. Experimental results combined with theoretical simulation indicated that V<sub>O</sub> strengthened CO<sub>2</sub> adsorption and activated *CO production, and plasmon-induced hot electrons from Au NPs to CeO<sub>2</sub>-V<sub>O</sub> facilitated the *CO-*CO dimerization. The synergistic modulation of V<sub>O</sub> and hot electrons further decreased the energy barriers of C-C coupling and subsequent hydrogenation, resulting in the superior photoreduction performance. This work opens an avenue of developing plasmonic photocatalysts for multi-carbon products from CO<sub>2</sub> photoreduction.