Bias-Adaptable CO<sub>2</sub>-to-CO Conversion via Tuning the Binding of Competing Intermediates
Yongxiang Liang, Jiankang Zhao, Han Zhang, An Zhang, Shilong Wang, Jun Li, Mohsen Shakouri, Qunfeng Xiao, Yongfeng Hu, Zuhuan Liu, Zhigang Geng, Fengwang Li, Jie Zeng
Abstract
CO2 electroreduction powered by renewable electricity represents a promising method to enclose anthropogenic carbon cycle. Current catalysts display high selectivity toward the desired product only over a narrow potential window due primarily to unoptimized intermediate binding. Here, we report a functional ligand modification strategy in which palladium nanoparticles are encapsulated inside metal–organic frameworks with 2,2′-bipyridine organic linkers to tune intermediate binding and thus to sustain a highly selective CO2-to-CO conversion over widened potential window. The catalyst exhibits CO faradaic efficiency in excess of 80% over a potential window from −0.3 to −1.2 V and reaches the maxima of 98.2% at −0.8 V. Mechanistic studies show that the 2,2′-bipyridine on Pd surface reduces the binding strength of both *H and *CO, a too strong binding of which leads to competing formate production and CO poison, respectively, and thus enhances the selectivity and stability of CO product.