Nickel metal particles encapsulated in carbon shells as efficient bifunctional electrocatalysts for urea-assisted hydrogen production

Abstract

Urea oxidation reaction (UOR) is considered an ideal water splitting reaction with the potential to replace oxygen evolution reaction (OER), as it lowers the anodic potential and utilizes urea as a renewable and abundant resource. However, creating stable, effective bifunctional catalysts is still challenging. In this work, we report a novel bifunctional catalyst of core-shell structure Ni-500 Nano-particle. The carbon coating not only offers numerous active sites and facilitates rapid charge transfer but also shields the nickel core from corrosion. Moreover, By replenishing the urea concentration, the current density can be recovered and sustained for 50 h with only an 8 % decrease. It is significantly less than pure water electrolysis that the urea-assisted water electrolyzer with Ni-500 as both cathode and anode achieves cell-voltage of 1.55 V at 100 mA cm−2. This work demonstrates the potential of Ni-500 as a inexpensive and effective catalyst for urea-based hydrogen production, and offers new perspectives into the design and optimization for core-shell structure electrocatalyst.