Microfluidic Synthesis of Channel‐Rich Pd‐Cu Alloy Nanodendrites for Efficient Electrocatalytic CO 2 Reduction to Formate

Abstract Palladium is a viable material for electrocatalytic CO 2 reduction to formate due to its high Faraday efficiencies (FEs) at relatively low potentials, but its durability is plagued by unavoidable surface CO poisoning. Herein, alloying and structural engineering are combined to develop Pd‐based catalysts with enhanced formate activity and CO tolerance. A series of Pd‐Cu alloy nanocatalysts with tunable compositions and morphologies is synthesized using a microfluidic system, and the mechanistic details are also investigated through experimental and computational approaches. Among them, channel‐rich Pd 1 Cu 1 alloy nanodendrites demonstrate the best performance, with a formate FE of 97.7% at −0.1 V RHE and maintaining FEs above 90% across a broad potential range of −0.05 – −0.25 V RHE . In situ spectroscopic analysis and density functional theory calculations reveal that alloying Pd with Cu favors the formate production pathway while mitigating CO‐related poisoning. Moreover, the channel‐rich structure plays a crucial role in accumulating K + , effectively enhancing electrocatalytic CO 2 reduction.