Vertically Aligned Porous Nickel(II) Hydroxide Nanosheets Supported on Carbon Paper with Long-Term Oxygen Evolution...

Vertically aligned Ni(OH)₂ nanosheets were grown on carbon paper (CP) current collectors through a simple and cost-effective hydrothermal approach. The as-grown nanosheets are porous and highly crystallized. If used as a monolithic electrode for electrochemical water oxidation in alkaline solution, the carbon paper supported Ni(OH)₂ nanosheets [CP@Ni(OH)₂ ] exhibit high electrocatalytic activity and excellent long-term stability. The electrode can attain an anodic current density of 20 mA cm^-2 at a low overpotential of 338 mV, comparable to that of state-of-the-art RuO₂ nanocatalysts supported on CP (CP/RuO₂ ) with the same catalyst loading. Significantly, CP@Ni(OH)₂ shows much better long-term stability than CP/RuO₂ upon continuous galvanostatic electrolysis, particularly at a high industry-relevant current density such as 100 mA cm^-2 . CP@Ni(OH)₂ can sustain water oxidation at 100 mA cm^-2 for 50 h without any degradation, whereas the performance of CP/RuO₂ is much poorer and deteriorates gradually over time. CP@Ni(OH)₂ electrodes hold substantial promise for use as low-costing water oxidation anodes in electrolyzers.