S,N dual-doped carbon nanotubes as substrate to enhance the methanol oxidation performance of NiO nanoparticles

Surface atomic engineering of substrates provides an efficient way to further improve the catalytic activity and stability of coupled catalysts for methanol oxidation. In this paper, S,N dual-doped carbon nanotubes (S,N-CNTs) with high doping levels of S (4.78 at%) and N (3.58 at%) were generated by laser irradiation, and used as substrate to in-situ load NiO nanoparticles (NPs). S and N atoms in CNTs provided abundant anchor sites for NiO NPs to restrain their growth, strengthen the interaction between NiO NPs and CNTs, and promote the interfacial electron transportation. Therefore, electrochemical tests demonstrated that NiO/S,N-CNTs shown a high primary methanol oxidation activity of 2200 mA/mg, a long-term durability with 65.8% of mass activity maintained after 40000s, and an excellent methanol saturation concentration of 13 M. This work provides a facile strategy to fabricate S,N-CNTs and helps to understand the effect of heteroatoms in carbonaceous substrates on boosting the electroactivity of coupled catalysts.

载体表面原子工程是进一步提升甲醇氧化耦合催化剂催化活性与稳定性的高效途径。本文通过激光辐照法制备了硫、氮双掺杂碳纳米管（S,N-CNTs），其硫掺杂量达4.78原子百分比（at%）、氮掺杂量达3.58原子百分比（at%），并以此为载体原位负载氧化镍纳米颗粒（NPs）。碳纳米管中的硫、氮原子可为氧化镍纳米颗粒提供丰富的锚定位点，抑制其团聚生长，强化氧化镍纳米颗粒与碳纳米管之间的界面相互作用，同时促进界面电子传输。电化学测试结果表明，NiO/S,N-CNTs展现出2200 mA/mg的优异初始甲醇氧化活性、经40000秒测试后仍保留65.8%质量活性的出色长期耐久性，以及可达13 M的优异甲醇饱和浓度。本研究为S,N-CNTs的制备提供了一种简便策略，同时有助于深入理解碳质载体中的杂原子对提升耦合催化剂电催化活性的作用机制。