Transition metal oxide-based catalysts are known as the most active oxygen evolution reaction (OER) catalysts due to their intrinsic electronic structures and binding strength of oxygenated intermediates. However, even the most active transition metal oxide-based OER catalysts have a turnover frequency far lower than that of the oxygen-evolving complexes in biological systems for intermolecular site aggregation. Herein, we implement the hybridization of a metal–organic framework and tungstic acid (WO3·xH2O-in-MIL-88) to achieve ordered FeNi site isolation at the molecular level and avoid intermolecular decomposition during the catalysis process. The optimized hybrid with 15% tungstic acid (15%-WO3·xH2O-in-MIL-88) achieves a much-enhanced OER activity and stability in terms of a low overpotential of 263 mV to reach a current density of 10 mA cm−2, a low Tafel slope of 39 mV dec−1, and long-term stability, which is much superior to that of the commercial RuO2 catalyst.
Jialei Jin,Yuanzhi Zhu,Yizhe Liu,Yang Li,Wenchao Peng,Guoliang Zhang,Fengbao Zhang,Xiaobin Fan
Producing hydrogen through hydrogen evolution reaction by electrolyzing water is a great alternative to solve the energy crisis and air pollution. Earth abundant transition-metal phosphides, especially CoP , have emerged as promising hydrogen evolution reaction catalysts for recent years. Nowadays, attention is focused on combining CoP with other materials to improve its catalytic activity . Herein, in order to get better hydrogen evolution reaction catalyst, we combined CoP nanoparticles with WS 2 nanosheets. Different CoP to WS 2 mass ratios were set to find the best catalytic activity. CoP/WS 2 composites were prepared through a simple ultrasound induced mixing method. And all the CoP/WS 2 composites have enhanced hydrogen evolution reaction catalytic activity than pure CoP nanoparticles and WS 2 nanosheets. Especially, the optimized CoP/WS 2 composite has the lowest onset overpotential of 50 mV, the largest current density of 78 mA/cm 2 at the overpotential of 300 mV, and the smallest Tafel slope of 64.63 mV/decade, indicating excellent hydrogen evolution reaction catalytic activity.
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