磷/氮共掺杂协同促进空心碳纳米球碱性电催化析氢

Combined effect of P/N co-doping in hollow carbon nanospheres for electrocatalytic alkaline hydrogen evolution

  • 摘要: 合理制备经济高效的无金属碳基析氢反应(HER)电催化剂,对于推动碱性水电解制备清洁氢技术的蓬勃发展具有重要意义。通过杂原子掺杂精细调控电子结构已被证明能有效提升材料的本征催化活性。然而,由于缺乏对其基本结构特征和机理的深入研究,尤其是对双杂原子掺杂研究仍然非常模糊,阻碍了无金属碳基HER催化剂的实际应用。本文采用胶束界面共聚合技术,在Triton X-100 水溶液中引发吡咯和苯胺共聚合形成空心聚合物球,接着通过植酸掺杂和碳化成功制备了磷/氮共掺杂空心碳纳米球(HCNs)。HCNs独特的孔隙结构和缺陷框架促进了大量活性位点的暴露。此外,石墨化氮(N―Q)和磷-碳(P―C)键的协同耦合效应调节了相邻碳原子的局部电子结构,促进了电子转移。因此,在1100°C下碳化的HCNs具有更大比例的N―Q和P―C键,表现更优的碱性HER活性和出色的稳定性(70 h@10 mA cm−2)。

     

    Abstract: Rational preparation of cost-effective and efficient metal-free carbon-based catalysts for hydrogen evolution reaction (HER) is of great significance for boosting the flourishing of clean hydrogen production from alkaline water electrolysis. Delicate regulation of the electronic structure via heteroatom doping has proven to be efficient for enhancing intrinsic catalytic activity. Nevertheless, both the structural characteristics and the underlying mechanism lack comprehensive investigation and remain greatly obscure especially for dual atoms doping, impeding the practical use of metal-free carbon-based HER catalysts. Herein, phosphorus/nitrogen co-doped hollow carbon nanospheres (HCNs) were successfully synthesized via the copolymerization of pyrrole and aniline at Triton X-100 micelle-interface, followed by doping with phytic acid and carbonization. The unique pore structure and defect frameworks of HCNs promote the exposure of numerous active sites. Crucially, the combined coupling effect of graphitized nitrogen (N―Q) and phosphorus-carbon (P―C) bonds modulates the local electronic structure of adjacent C atoms and facilitates electron transfer. Therefore, the HCN carbonized at 1100 °C exhibited superior alkaline HER activity and outstanding stability (70 h@10 mA cm−2), owing to the larger proportion of N―Q and P―C bonds.

     

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