Atomically Asymmetric Pd1─O─Cu Interfaces Break the Activity-Selectivity Limit in CO-to-Acetate Conversion.

Abstract

The electrochemical reduction reaction of CO (eCORR) to acetate is a pivotal pathway for carbon neutrality, yet it is persistently constrained by the linear scaling relations of the adsorption energetics of key intermediates. Consequently, conventional alloy catalysts often suffer from an activity-selectivity trade-off, failing to stabilize C─C coupling intermediates without poisoning active sites. Herein, we circumvent this thermodynamic limit by constructing atomically asymmetric Pd1─O─Cu interfaces derived from the partial operando reconstruction of a metal-organic framework (CuPd-THQ), where isolated Pd single atoms are anchored on Cu2O nanoislands (Pd/Cu2O/CuPd-THQ). The strong CO affinity of Pd drives the migration of remote *CO species toward the Pd center via a spillover effect. This catalyst achieves an industrial-level acetate Faradaic efficiency of 82.3% (purity of 96%) and sustains performance for over 400 h at 250 mA cm-2 under -1.0 V versus RHE, significantly outperforming conventional Cu-based catalysts. Furthermore, in a membrane electrode assembly (MEA) system, it delivers a remarkable acetate yield rate of 6367.7 mg L-1 h-1, demonstrating scalable viability. Mechanism studies reveal that this atomic-scale geometric isolation allows for the independent optimization of *CO and *CCO binding energetics. Our findings provide a generalizable strategy for breaking scaling relations in complex multi-electron electrocatalysis.