纳米针尖状质子化聚苯胺负载的单原子铂催化剂实现高效酸性电解水制氢

Atomically dispersed platinum supported onto nanoneedle-shaped protonated polyaniline for efficient hydrogen production in acidic water electrolysis

开发高性能单原子铂催化剂对酸性电解水制氢领域具有重要意义.在酸性电解液中,氢离子(H^(+))会被水分子包围并形成水合氢离子,这会导致单原子铂活性位点的局部H^(+)浓度降低,从而使其析氢反应动力学受到限制.本研究通过将单原子铂负载在纳米针尖状质子化聚苯胺上,它既能捕获水合氢离子中的H^(+),又能通过促进电荷积累以加快H^(+)的电化学还原,从而提高单原子铂的析氢反应动力学.结果表明,相比于扁平状质子化聚苯胺负载的单原子铂,针尖状质子化聚苯胺负载的单原子铂的析氢反应转换频率得到显著提高.结合X射线光电子能谱、有限元模拟和电化学行为研究,我们发现局部H^(+)富集促使的氢溢流现象对提升纳米针尖状质子化聚苯胺负载的单原子铂催化剂的析氢活性具有重要贡献.

Developing high-performance single-atom platinum(Pt)catalysts for acidic hydrogen evolution reaction(HER)is of significance.However,their HER kinetics are limited due to the low concentration of hydrogen ions(H^(+))near the Pt sites in acidic electrolytes,where hydronium ions are undesirably formed with H^(+)surrounded by water molecules.Here,we seek to improve the HER kinetics by anchoring single-atom Pt catalyst on nanoneedle-shaped protonated polyaniline supports,which can not only capture H^(+)from the hydronium ions but also facilitate the electroreduction of H^(+)by promoting the electron accumulation.As a result,the turnover frequency of single-atom Pt supported on the nanoneedle-shaped protonated polyaniline is appreciably enhanced,compared with that of the single-atom Pt supported on the flat-shaped protonated polyaniline.By combining the X-ray photoelectron spectroscopy,finite-element simulation and electrochemical studies,we find that the enhanced HER activity of single-atom Pt on nanoneedle-shaped protonated polyaniline support may arise from a hydrogen spillover pathway induced by the increased local concentration of H^(+)near the Pt sites.