A stable and highly active core-shell heterostructure electrocatalyst is essential for catalyzing oxygen evolution reaction (OER). Here, a dual-trimetallic core-shell heterostructure OER electrocatalyst that consists of a NiFeWS₂ inner core and an amorphous NiFeW(OH)_z outer shell is designed and synthesized using in situ electrochemical tuning. The electrochemical measurements of different as-synthesized catalysts with a similar mass loading suggest that the core-shell Ni_0.66Fe_0.17W_0.17S₂@amorphous NiFeW(OH)_z nanosheets exhibit the highest overall performance compared with that of other bimetallic reference catalysts for the OER. Additionally, the nanosheet arrays were in situ grown on hydrophilic-treated carbon paper to fabricate an integrated three-dimensional electrode that affords a current density of 10 mA cm⁻² at a small overpotential of 182 mV and a low Tafel slope of 35 mV decade⁻¹ in basic media. The Faradaic efficiency of core-shell Ni_0.66Fe_0.17W_0.17S₂@amorphous NiFeW(OH)_z is as high as 99.5% for OER. The scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy analyses confirm that this electrode has excellent stability in morphology and elementary composition after long-term electrochemical measurements. Importantly, density functional theory calculations further indicate that the core-shell heterojunction increased the conductivity of the catalyst, optimized the adsorption energy of the OER intermediates, and improved the OER activity. This study provides a universal strategy for designing more active core-shell structure electrocatalysts based on the rule of coordinated regulation between electronic transport and active sites.

中文翻译：

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异质结构 NiFeW 二硫化物和氢氧化物双三金属核壳纳米片用于协同有效的水氧化

稳定且高活性的核壳异质结构电催化剂对于催化析氧反应（OER）至关重要。在这里，利用原位电化学调谐设计并合成了由 NiFeWS ₂内核和非晶 NiFeW(OH) _z外壳组成的双三金属核壳异质结构 OER 电催化剂。对具有相似质量负载的不同合成催化剂的电化学测量表明，与其他双金属参考催化剂相比，核壳 Ni _0.66 Fe _0.17 W _0.17 S _{2 @}非晶态 NiFeW(OH) _z纳米片表现出最高的整体性能。开放教育资源。此外，纳米片阵列在亲水处理的碳纸上原位生长，以制造集成的三维电极，该电极在182 mV的小过电势和35 mV十倍频程的低塔菲尔斜率下提供10 mA cm ^-2的电流密度基本媒体中为^{-1 。}核壳Ni _0.66 Fe _0.17 W _0.17 S ₂ @非晶态NiFeW(OH) _z的OER法拉第效率高达99.5%。扫描电镜、透射电镜和X射线光电子能谱分析证实，经过长期电化学测量，该电极在形貌和元素组成方面具有优异的稳定性。重要的是，密度泛函理论计算进一步表明核壳异质结提高了催化剂的电导率，优化了OER中间体的吸附能，提高了OER活性。该研究为基于电子传输和活性位点之间协调调控的规则设计更具活性的核壳结构电催化剂提供了通用策略。