Electrochemical semi-sacrificial growth of Ni-HCP nanoplate arrays for urea/methanol electrooxidation-coupled water electrolysis

Efficient Ni-based catalysts for small organic molecule electrooxidation are crucial yet challenging to develop. This study presents self-supported nickel-nickel Hofmann-type coordination polymer nanoplate arrays (Ni-HCP-t/NF) synthesized through an electrochemical semi-sacrificial growth strategy. By controlling the growth time of Ni-HCP-t nanoplates, we optimized the structure and electrochemical performance, with Ni-HCP-40/NF exhibiting significant bifunctional electrocatalytic activity for urea and methanol oxidation reactions (UOR and MOR), achieving a current density of 100 mA cm⁻² at only 1.44 and 1.46 V (vs. RHE), respectively. Moreover, urea-water and methanol-water electrolysis systems using Ni-HCP-40/NF as the anode demonstrate reduced voltages of 1.61 and 1.64 V for urea-water and methanol-water electrolysis at 100 mA cm⁻², respectively, dramatically lower than water electrolysis (1.85 V). The superior UOR/MOR activities are attributed to the abundant and fully exposed Ni sites and efficient electron/mass transfer rate facilitated by three-dimensional nanoplate architecture. © 2024 Elsevier Ltd.