Highly Selective Photocatalytic CO<sub>2</sub> Reduction to C<sub>2</sub>H<sub>6</sub> via Nanocluster-Single Atom-Vacancy on Ceria: Synergistic Mechanism and Orbital Effects
Yingnan Duan, Hexiang Zhao, Jixiang Ji, Zhurui Shen, Y. F. Wang, Yaping Du
Abstract
The photocatalytic reduction of CO 2 to high-value C 2 products involves sluggish multiple proton–electron couplings, resulting in low efficiency and selectivity. This study demonstrates that palladium (Pd) single-atom (Pd SA )- and Pd nanocluster (Pd NCs )-loaded CeO 2 with abundant oxygen vacancies (O v ) synergistically enhance photocatalytic CO 2 -to-ethane (C 2 H 6 ) conversion effectively and selectively. The Pd SA+NCs /CeO 2 photocatalyst achieves 80.4% electron selectivity for C 2 H 6 production with an electron consumption rate of 206.3 μmol g cat –1 h –1 in pure water, representing a 172.4-fold enhancement over pristine CeO 2 . Pd NCs interact with neighboring Pd SA and O v to form a Fermi level with the continuous characteristics of discrete energy levels, improving the charge distribution in local spatial electric fields. This enhancement favors electron migration from the π to σ orbital of COCO*, promoting C–C coupling. Our findings provide new insights to rationally design synergistic interactions between SA, NCs, and O v to achieve high selectivity toward C 2 products.