Improving utilization of precious metals is one of the crucial challenges for electrochemical energy catalysis. Tuning precious metal structure to expose active sites is an effective strategy to reduce mass loading in the practical application. Herein, Pt-Co hollow nanospheres were synthesized via a sequential reduction strategy using amorphous Co-B-O complex as the key spheres-forming intermediates. The modulation mechanism of Pt-Co hollow nanospheres formation was established by investigating critical factors of addition sequence of reducing agent, the type of reducing agents and the ratio of Pt and Co precursors. The optimized Pt-Co hollow nanospheres with the Pt/Co molar ratio of 1:1 by this method is characterized by the average diameter of around 30 nm and the shell thickness of 2.3 nm. They displays superior performance for enhanced hydrogen evolution reaction (HER) in the aspect of activity and stability in 0.5 M H₂SO₄, in which the mass activity of the Pt-Co hollow spheres exhibits 2.82 times higher than that of commercial Pt/C and its stability also has a significant enhancement. The outstanding activity of the Pt-Co hollow nanospheres for HER is mainly attributed to its highly accessible electron/mass transport path, expose active sites on the ultra-thin shells and strain effect induced by the hollow sphere structure. This hollow nanospheres with ultra-thin shell provides a promising way to develop highly efficient precious metal based electrocatalysts.

提高贵金属的利用率是电化学能量催化的关键挑战之一。在实际应用中，调整贵金属结构以暴露活性位点是减少质量负荷的有效策略。在这里，Pt-Co空心纳米球是通过顺序还原策略合成的，使用非晶态Co-BO络合物作为关键的形成球的中间体。通过研究还原剂添加顺序，还原剂类型和Pt与Co前驱体比例的关键因素，建立了Pt-Co中空纳米球形成的调控机理。通过该方法优化的Pt / Co摩尔比为1：1的Pt-Co空心纳米球的特征是平均直径约为30 nm，壳厚度为2.3 nm。₂ SO ₄，其中Pt-Co空心球的质量活度比市售Pt / C高2.82倍，并且其稳定性也有显着提高。Pt-Co空心纳米球对HER的杰出活性主要归因于其高度可访问的电子/质量传输路径，暴露了超薄壳上的活性位以及空心球结构引起的应变效应。具有超薄壳的中空纳米球为开发高效的贵金属基电催化剂提供了一种有前途的方法。