Rational design of low‐cost, highly efficient, and stable electrocatalysts for the hydrogen evolution reaction (HER) has attracted wide attention. Herein, 3D RuCu nanocrystals (NCs) are successfully synthesized by a facile wet chemistry method, in which amorphous RuCu nanosheets are directly grown on crystalline Cu nanotubes (NTs). Importantly, the obtained 3D RuCu NCs only need 18 and 73 mV to deliver the current density of 10 mA cm⁻² for HER in alkaline and neutral media, respectively. Density functional theory calculations and experiments reveal that the Ru sites on the surface of amorphous nanosheets are the highly active centers for HER. Moreover, this catalyst can expose more surface area for water splitting compared to pure nanosheets because the unique 3D structure can effectively prevent the aggregation of nanosheets. Meanwhile, the interface between amorphous nanosheets and crystalline NTs is essential to boost the HER performance because the amorphous phase with many unsaturated bonds can facilitate adsorption of reactants and crystalline Cu with superior conductivity can promote the transfer of electrons. This work provides a facile method to prepare an original 3D Ru‐based electrocatalyst with highly active HER performance in wide pH values.

中文翻译：

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高活性非晶态RuCu纳米片在Cu纳米管上的生长，用于在宽pH值下进行氢分解反应。

低成本，高效，稳定的氢析出反应（HER）电催化剂的合理设计引起了广泛关注。在此，通过简便的湿化学方法成功地合成了3D RuCu纳米晶体（NCs），其中非晶态RuCu纳米片直接生长在晶体Cu纳米管（NTs）上。重要的是，获得的3D RuCu NC仅需要18和73 mV即可提供10 mA cm ^-2的电流密度分别用于碱性和中性介质中的HER。密度泛函理论计算和实验表明，非晶态纳米片表面的Ru位是HER的高活性中心。此外，与纯纳米片相比，该催化剂可暴露更多的表面积用于水分解，因为独特的3D结构可有效防止纳米片的聚集。同时，非晶纳米片和晶体NT之间的界面对于提高HER性能至关重要，因为具有许多不饱和键的非晶相可以促进反应物的吸附，而具有优异电导率的晶体Cu可以促进电子的转移。这项工作提供了一种简便的方法来制备原始的3D Ru基电催化剂，在宽pH值下具有高度活性的HER性能。