Dual cation-modified hierarchical nickel hydroxide nanosheets arrays as efficient and robust electrocatalysts for urea oxidation reaction

The rational modification of electronic structures for catalytic active sites has been proved to be a promising strategy to facilitate efficient urea oxidation reaction (UOR). Herein, in this work, a well-defined nanosheets arrays catalyst of Ni(OH)2 doped with dual cation of Co and Mn on Ni foam (NF) (Co/Mn-Ni(OH)2) is synthesized though a simple hydrothermal process. Benefiting from the advantages of unique structures and modified binding strengths, it is found experimentally that the obtained Co/Mn-Ni(OH)2 catalyst only requires a potential of 1.38 V to deliver the current density of 100 mA cm-2 and a low Tafel slope of 35 mV dec-1, outperforming the single-component incorporated Ni(OH)2. Moreover, it has been shown the excellent stability for 25 h at the current density of 50 mA cm-2. Additionally, the first-principles calculations demonstrate that the co-incorporation of Co and Mn remarkably lowers the adsorption barrier of CO(NH2)2* on catalyst surface, and accelerates the dissociation CO(NH2)2* intermediate to CO* and NH* intermediate, which synergistically improves the UOR reaction kinetics. This work provides a well generic paradigm for designing advanced and effective catalysts toward UOR.