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.

A series of N-doped carbon materials (NCs) were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile one-step pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C₃N₄ with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6, show the highest N content of ~6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of ~66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal–air batteries.