The lack of well-performing, atom-economic, earth-abundant, transition metal electrocatalysts for the oxygen evolution reaction (OER) in water electrolysers and rechargeable metal–air batteries remains an impediment for their ubiquitous application. Accordingly, nickel oxide has attracted attention as a potential OER catalyst, but its inferior catalytic activity due to the non-participation of its concealed active sites is challenging. Herein, a reported nitrogen-doped graphitic carbon shell-embedded nickel nanoparticle electrocatalyst (Ni-D-700) was investigated to enhance its oxygen evolution activity via the surface dissolution method. This method, which is widely used for dealloying bimetallic nanoparticles to improve their activity, was employed to study the effect of leaching and its duration on a monometallic nanoparticle catalyst. The resultant oxide layer formed on the surface of the nickel nanoparticles (Ni⁰@Ni²⁺/Ni³⁺) exhibited outstanding oxygen evolution activity (1.52 V onset potential vs. RHE, 53.4 mV dec⁻¹ Tafel slope and 360 mV overpotential at 10 mA cm⁻² current density) and mass activity, much higher than that of the precursor catalyst. This is attributed to the participation of maximum metal/metal oxide interfaces generated in the process of leaching, which otherwise tend to remain subdued, leading to insufficient catalytic activity.

中文翻译：

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通过表面溶解增强掺氮石墨碳壳嵌入的镍/氧化镍纳米粒子的析氧活性

在水电解池和可充电金属-空气电池中，缺乏用于氧释放反应（OER）的性能良好，原子经济，富含地球的过渡金属电催化剂，仍然是其普遍应用的障碍。因此，氧化镍作为潜在的OER催化剂已经引起了人们的注意，但是由于其隐蔽的活性位点的不参与，其催化活性较差。在此，研究了一种报道的氮掺杂石墨碳壳包埋的镍纳米粒子电催化剂（Ni-D-700），以通过以下方式增强其氧释放活性：表面溶解法。该方法被广泛用于脱金属双金属纳米颗粒以提高其活性，该方法用于研究浸出的影响及其持续时间对单金属纳米颗粒催化剂的影响。形成在镍纳米粒子（Ni ⁰ @Ni ²⁺ / Ni ³⁺）表面上的所得氧化物层表现出出色的氧释放活性（相对于RHE的1.52 V起始电势，53.4 mV dec ^-1 Tafel斜率和360 mV的超电势）。 10 mA厘米^-2电流密度）和质量活性，远高于前体催化剂。这归因于在浸出过程中产生的最大的金属/金属氧化物界面的参与，否则它们倾向于保持柔和，从而导致不足的催化活性。