Electrocatalytic activation of organic chlorides via direct and indirect electron transfer using atomic vacancy control of palladium-based catalyst

Electrocatalytic dehalogenation (EDH) is a promising green technology for the breakage of strong carbon-chlorine (C-Cl) bonds that have fundamental importance in organic chemistry and environmental remediation. The lack of fundamental understanding and practical issues such as potential secondary pollution, side reactions (e.g., hydrogen-evolution reaction), deficiency in catalytic activity, and/or stability have limited the adoption of EDH technology. Here, we address these problems by designing a palladium-based nanocatalyst with precise control of atomic vacancies to exploit the combination of direct and indirect EDH. Experimental and theoretical investigations show that atomic vacancies can promote electron transfer on the catalyst surface to enhance the generation/storage capacity of atomic hydrogen and to simultaneously facilitate dissociative electron transfer to C-Cl bond. Our work guides the design of atomic-vacancy-rich palladium-based electrocatalysts and provides a new strategy for efficient electro-dehalogenation in water and fundamental insights into the relationship of different dehalogenation mechanisms for accurate quantitative prediction.