Cai Huizhu, Yang Hengpan, He Sizhen, Wan Da, Kong Yan, Li Deliang, Jiang Xingxing, Zhang Xue, Hu Qi, He Chuanxin
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, 518060, China.
Angew Chem Int Ed Engl. 2025 Mar 24;64(13):e202423765. doi: 10.1002/anie.202423765. Epub 2025 Jan 13.
The high entropy alloy (HEA) possesses distinctive thermal stability and electronic characteristics, which exhibits substantial potential for diverse applications in electrocatalytic reactions. The nanosize of HEA also has a significant impact on its catalytic performance. However, accurately controlling nanosize and synthesizing small HEA nanomaterials remains a challenge, especially for the ultrasmall HEA nanoparticles. Herein, we firstly calculate and illustrate the impact of size on the electronic structure of HEA as well as the adsorption energies of crucial intermediates involved in typical electrocatalytic processes, such as the hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), CO electroreduction (CORR) and NO electroreduction (NORR). Under the guidance of theoretical calculations, we synthesize a range of ultrasmall PtRuPdCoNi HEA nanoparticles with adjustable sizes (1.7, 2.3, 3.0, and 3.9 nm) using a one-step spatially confined approach, without any further treatment. Experimentally, the smaller size of HEAs is more favorable for the HER and ORR performances, aligning well with theoretical predictions. Specifically, HEA nanoparticles sized at 1.7 nm (HEA-1.7) endows a 16 mV overpotential at current density of 10 mA cm, yielding a mass activity of 31.9 A mg of noble metal in HER, significantly outperforming commercial Pt/C catalyst. This strategy can also be easily applicable to other reduction reactions (e.g. CO, NO ) attributed to the richness of metal components and size adjustability, presenting a promising platform for various electrocatalytic applications as advanced catalysts.
高熵合金（HEA）具有独特的热稳定性和电子特性，在电催化反应的多种应用中展现出巨大潜力。HEA的纳米尺寸对其催化性能也有重大影响。然而，精确控制纳米尺寸并合成小型HEA纳米材料仍然是一项挑战，特别是对于超小的HEA纳米颗粒而言。在此，我们首先计算并阐明尺寸对HEA电子结构以及典型电催化过程中关键中间体吸附能的影响，这些过程包括析氢反应（HER）、氧还原反应（ORR）、CO电还原（CORR）和NO电还原（NORR）。在理论计算的指导下，我们采用一步空间限制法合成了一系列尺寸可调（1.7、2.3、3.0和3.9 nm）的超小PtRuPdCoNi HEA纳米颗粒，无需任何进一步处理。实验表明，较小尺寸的HEA对HER和ORR性能更有利，与理论预测结果吻合良好。具体而言，尺寸为1.7 nm的HEA纳米颗粒（HEA-1.7）在电流密度为10 mA cm时具有16 mV的过电位，在HER中贵金属的质量活性为31.9 A mg，显著优于商业Pt/C催化剂。由于金属成分丰富且尺寸可调，该策略还可轻松应用于其他还原反应（如CO、NO），为各种电催化应用提供了一个有前景的先进催化剂平台。
