Electrocatalytic Hydrogenation of Pyrazine by Cu 0.95 Co 2.05 O 4 : Kinetics, Mechanism, and Performance

ABSTRACT Hydrogen storage remains a key challenge for hydrogen utilization. Liquid organic hydrogen carriers (LOHCs) are promising, but their practical application is limited by the harsh conditions of conventional thermal catalysis. Electrochemical hydrogenation offers a mild and safe alternative. Herein, nickel foam (NF), Co 3 O 4 /NF, Cu 2 O/NF, and Cu 0.95 Co 2.05 O 4 /NF are evaluated as electrocatalysts for pyrazine hydrogenation to piperazine. Cu 0.95 Co 2.05 O 4 /NF exhibited superior performance, achieving a current density of −56.3 mA cm − 2 at −0.2 V (vs. RHE). After 2 h, pyrazine conversion reached 99.8% with 96.1% piperazine selectivity, retaining 79.7% after 10 cycles. Mechanistic studies suggest Co sites generate active H* via the Volmer step, which migrates to Cu sites for pyrazine hydrogenation. The Cu–Co synergy enhances both H* formation and substrate adsorption. This process eliminates the need for external H 2 , improving system safety and demonstrating its potential for efficient LOHC hydrogenation.