Ultrathin nanosheet metal-organic framework@NiO/Ni nanorod composites

Abstract Two-dimensional metal-organic frameworks are a family of materials with great potential for electrocatalysis; however, these materials usually have the poor thermodynamic stability and require harsh preparation conditions. Here, we describe a facile approach for preparing ultrathin nanosheet metal-organic framework@NiO/Ni nanorods with increased stability and highly active sites compared with in case of pristine metal-organic frameworks. These peculiar hierarchical nanocomposites exhibit excellent properties for urea electrolysis, including abundant exposed active sites owing to their nanosheet-nanorod hierarchical structure, enriched Ni-species, and improved stability. The prepared composites demonstrate superior electrocatalytic performance toward the urea oxidation reaction with a low overpotential of only 170 mV to reach 10 mA cm-2, a small Tafel slope of 48.1 mV dec-1, and a low cell voltage of 1.42 V for overall urea electrolysis, with outstanding long-term durability (15,000 s with only 7.1% activity decay). This combination between metal-organic frameworks and materials with high thermodynamic stability offers a strategy for further development of excellent electrocatalysts.