Zhou Haiqing, Yu Fang, Sun Jingying, He Ran, Chen Shuo, Chu Ching-Wu, Ren Zhifeng
Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204.
Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, TX 77204;
Proc Natl Acad Sci U S A. 2017 May 30;114(22):5607-5611. doi: 10.1073/pnas.1701562114. Epub 2017 May 15.
Commercial hydrogen production by electrocatalytic water splitting will benefit from the realization of more efficient and less expensive catalysts compared with noble metal catalysts, especially for the oxygen evolution reaction, which requires a current density of 500 mA/cm at an overpotential below 300 mV with long-term stability. Here we report a robust oxygen-evolving electrocatalyst consisting of ferrous metaphosphate on self-supported conductive nickel foam that is commercially available in large scale. We find that this catalyst, which may be associated with the in situ generated nickel-iron oxide/hydroxide and iron oxyhydroxide catalysts at the surface, yields current densities of 10 mA/cm at an overpotential of 177 mV, 500 mA/cm at only 265 mV, and 1,705 mA/cm at 300 mV, with high durability in alkaline electrolyte of 1 M KOH even after 10,000 cycles, representing activity enhancement by a factor of 49 in boosting water oxidation at 300 mV relative to the state-of-the-art IrO catalyst.
与贵金属催化剂相比，通过电催化水分解进行商业制氢将受益于更高效、成本更低的催化剂的实现，特别是对于析氧反应而言，该反应需要在低于300 mV的过电位下实现500 mA/cm²的电流密度并具备长期稳定性。在此，我们报道了一种由负载于可大规模商购的自支撑导电泡沫镍上的偏磷酸亚铁组成的稳健析氧电催化剂。我们发现，这种催化剂可能与表面原位生成的镍铁氧化物/氢氧化物和羟基氧化铁催化剂有关，在177 mV的过电位下可产生10 mA/cm²的电流密度，在仅265 mV的过电位下可达到500 mA/cm²，在300 mV时可达1705 mA/cm²，在1 M KOH的碱性电解液中即使经过10000次循环仍具有高耐久性，相对于最先进的IrO₂催化剂，在300 mV下促进水氧化的活性提高了49倍。
