Synergistic effect of asymmetric Ru-Pd dual single-atom-sites and Pd nanoparticles on carbon nitride for efficient CO2 photoreduction

• Published in: Applied catalysis. B, Environmental Environmental, 2025-05, Vol.365, Article 124917
• Main Authors: Ding, Cheng, Yang, Liuqing, Lu, Xinxin, Chi, Haoqiang, Yang, Yong, Zhang, Yongcai, Yuan, Junyang, Wang, Xiaoyong, Zhou, Yong, Zou, Zhigang
• Format: Article
• Language: English
• Subjects: CO2 photoreduction; Palladium; Ruthenium; Single-atom catalysts; Symmetry-breaking; Synergistic effect
• ISSN: 0926-3373
• DOI: 10.1016/j.apcatb.2024.124917

Precisely modulating the coordination environment of active centers in single-atom catalysts (SACs) remains a significant challenge. Herein, a Ru-Pd dual single atoms (SAs) (exist as Ru-N3, Pd-N1) and Pd nanoparticles (NPs) co-modified carbon nitride (CN) photocatalyst (RuSAsPdSAs+NPs-CN) with broken symmetry is creatively constructed based on local planar-like symmetric RuSAs-CN (Ru-N4). Benefiting from microstructure modulated by Pd-species-induced symmetry-breaking, RuSAsPdSAs+NPs-CN exhibits excellent CO2 photoreduction activity with a CO yield up to 177.38 μmol g−1 h−1, which is 19.91- and 1.86-fold higher than that of pure CN and RuSAs-CN. Moreover, apparent quantum efficiency (AQE) is up to 0.65 %, CO selectivity reaches 98.4 %, and shows good stability. Experimental and computational analyses confirm the Ru-N3 and Pd-N1 sites could serve as fast electron-transfer channels and accelerate photo-induced carriers' separation/transfer with the synergistic effect of Pd NPs. Meanwhile, the synergistic effect of Ru-Pd dual SAs sites with Pd NPs promotes CO2 adsorption/activation, lowers the *COOH formation energy barrier, and optimizes reaction pathways. Furthermore, calculations indicate that excellent photocatalytic activity mainly originates from the symmetry-broken Ru-N3 sites. This work proposes a symmetry-breaking strategy to modulate electronic structure of active centers for CO2 reduction, providing new insights into rational design of efficient and highly selective CN-based single-atom photocatalysts. [Display omitted] •Asymmetric Ru-Pd dual single atoms and Pd nanoparticles co-modified carbon nitride (RuSAsPdSAs+NPs-CN) is constructed.•RuSAsPdSAs+NPs-CN exhibits excellent CO2 photoreduction activity, much higher than that of pure CN and RuSAs-CN.•The synergistic effect of Ru-N3, Pd-N1, and Pd NPs sites endows RuSAsPdSAs+NPs-CN with excellent catalytic activity.•DFT calculations indicate that the symmetry-broken Ru-N3 site is the major active center.