Reconstruction-induced NiCu-based catalysts towards paired electrochemical refining

Abstract

A paired electrochemical refinery toward the cathodic nitrate reduction reaction (NO₃RR) and anodic glycerol oxidation reaction (GOR) driven by renewable electricity could generate high value-added ammonia and formic acid simultaneously. However, both cathode and anode electrocatalysts often suffer from low efficiency and unclear reconstruction. Herein, we prepare a non-noble NiCu–OH nanocomposite precatalyst composed of crystalline Cu₂(OH)₃(NO₃) and amorphous Ni(OH)₂, which can be reconstructed into high-activity and stable cathodic NO₃RR and anodic GOR electrocatalysts under operating conditions. Various in situ and ex situ experiments demonstrate that NiCu–OH could convert into active Cu nanoparticles coupled with amorphous Ni(OH)₂ under cathodic NO₃RR conditions. Meanwhile, under anodic GOR conditions, NiCu–OH-derived bimetal oxide (NiCuO) changes into active NiOOH species composited with Cu vacancy-rich CuO. Furthermore, an actual paired electrochemical refinery with the reconstructed NiCu-based catalysts toward the NO₃RR and GOR shows a low potential of 1.37 V at a current density of 100 mA cm⁻² to continuously produce ammonium and formate. This study provides a new paradigm for the design of an electrochemical refinery with reconstructed non-noble electrocatalysts toward chemical upgradation.