Pressure-Driven Fabrication of Zn-Doped Co₃C@Carbon Nano-Onions for Robust Oxygen Evolution Reaction

Despite being an essential half-reaction for splitting water, the oxygen evolution reaction (OER) is rarely used in the industry because it is slow and requires expensive catalysts. Here, in the present study, the nanosheet of Co₃C and carbon nano-onions (CNOs) have been prepared using an annealing process under high pressure, and Zn-doped Co₃C was additionally prepared to investigate the impact of doping on Co₃C nanosheet as an OER electrocatalyst. The synthesized electrocatalyst is portrayed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmet-Teller (BET), and Fourier transform infrared (FTIR). The standing nanoflakes are shaped on the nanosheets of Co₃C in the wake of the doping effect. The mesoporous nanoflakes Zn-Co₃C@CNO have shown striking OER activity requiring 1.45 V vs RHE as the beginning potential for the OER and required a 276 mV overpotential (η) at 10 mA cm^-2. Indeed, even the higher current densities of 50 and 78 mA cm^-2 were achieved individually at lower η of 301 and 345 mV, respectively. The prepared electrocatalyst has shown unusual activity fit for continuous oxygen gas evolution for more than 50 h. Such excellent OER performance can be credited to doping Zn particles into the lattice structure of Co₃C, along with nanoflakes like standing construction are shaped on the nanosheet of Co₃C and microporosity of arranged terminals are considered as efficient for higher OER activity.