Palladium-decorated mesoporous Cu2Se nanoribbons for enhanced electrocatalytic CO2 reduction to HCOOH and high-performance Li-CO2 batteries

Electrocatalytic CO 2 reduction reaction (eCO 2 RR) to formic acid (HCOOH) provides an economical solution for the utilization of renewable electricity and addressing climate challenges. However, the catalytic activity is limited by an inappropriate hydrogenation process and competitive hydrogen (H 2 ) evolution. Herein, we prepared palladium (Pd) nanoparticle-decorated mesoporous Cu 2 Se nanoribbons catalyst (Cu 2 Se-Pd). Pd nanoparticles induce charge transfer from Cu to Se, while promoting the hydrogenation of intermediates and suppressing the evolution of H 2 . Experimental results show that the optimal Cu 2 Se-Pd catalyst achieves a HCOOH Faradaic efficiency (FE) of 61.85% at a potential of − 0.9 V versus reversible hydrogen electrode (vs. RHE) in a flow cell. Cu 2 Se-Pd achieves a HCOOH partial current density of − 129.78 mA cm −2  at − 1.1 V vs. RHE, and operates stably for about 15 h at a constant current of − 100 mA cm −2 . To further couple the eCO 2 RR with energy storage, a Li–CO 2 battery device was assembled using Cu 2 Se-Pd as the cathode material. Battery performance tests show that the Li–CO 2 battery assembled with Cu 2 Se-Pd can stably charge and discharge for over 250 h at a current density of 100 mA g −1 . This work provides experimental insights into promoting eCO 2 RR to HCOOH through hydrogenation regulation.