The development of a facile and general strategy to simultaneously enhance the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities of bifunctional electrocatalysts is of great importance for practical applications. However, current strategies are usually restricted to monofunctional electrocatalysts owing to the opposite redox process at cathode and anode. Herein, we present a photogenerated-carrier-driven strategy to enhance the electrocatalytic HER and OER activities of transition-metal/semiconductor bifunctional electrocatalysts. The Ni/NiO heterostructured ultrathin nanosheet array supported on Ni foam (denoted as Ni/NiO-NF) is chosen as the model metal/semiconductor bifunctional electrocatalyst and exhibits 10- and 2.6-fold enhancement of mass activity for HER and OER, respectively, after exposure to light irradiation. The increase in water-splitting activities can be attributed to the transfer of photogenerated electrons from excited NiO to HER-active Ni and the accelerating formation of OER-active Ni^III/IV, respectively.

中文翻译：

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光生载流子提高了过渡金属/半导体金属氧化物双功能电催化剂的水分解活性

同时提高双功能电催化剂的析氢反应（HER）和析氧反应（OER）活性的简便通用方法的开发对于实际应用非常重要。然而，由于在阴极和阳极处相反的氧化还原过程，当前的策略通常限于单功能电催化剂。在这里，我们提出了一种光生载流子驱动的策略，以增强过渡金属/半导体双功能电催化剂的电催化HER和OER活性。选择负载在泡沫镍上的Ni / NiO异质结构超薄纳米片阵列（表示为Ni / NiO-NF）作为模型金属/半导体双功能电催化剂，其对HER和OER的质量活性分别提高10倍和2.6倍，暴露于光照射后。水分解活性的增加可以归因于光生电子从激发的NiO转移到HER活性Ni以及OER活性Ni的加速形成^{III / IV}。