MoS2/石墨烯/泡沫炭复合材料的析氢性能

MoS2/graphene/carbonized melamine foam composite catalysts for the hydrogen evolution reaction

  • 摘要: 以包覆石墨烯的炭化三聚氰胺泡沫作为支撑,通过水热法在三维泡沫炭上原位生长二硫化钼(MoS2)纳米片,合成出一系列的MoS2/石墨烯/泡沫炭复合材料。经XRD和TEM表征,拥有三维网络结构的炭基骨架被厚度为15~20 nm的MoS2纳米片均匀包裹。石墨烯包覆量对析氢性能影响很大,包覆浓度25 mg L-1的R-&CMMS-25析氢性能最佳,在10 mA cm-2电流密度下过电位为163 mV,相应的塔菲尔斜率为76 mV dec-1,相比之前未包覆石墨烯的复合材料,析氢性能得到了很大提升。通过阻抗谱间接表征材料的电子迁移效率,可以看出R&CMMS-25的阻抗值最低,这表明包覆适量还原氧化石墨烯能够加速电子迁移效率并进一步提升析氢性能。

     

    Abstract: A melamine-based carbon foam was obtained from a melamine foam (2 cm×2 cm×2 cm), which was then coated with graphene by immersing it in 400 mL of a suspension of reduced graphene oxide in water with concentrations of 25 to 100 mg/L. MoS2/graphene/carbonized melamine foam composites for use as catalysts for the hydrogen evolution reaction were synthesized by the hydrothermal growth of MoS2 nanosheets on the graphene-coated carbon foams in a mixed solution of molybdic acid disodium salt and thiourea. Results indicate that MoS2 nanosheets with a thickness of 15-20 nm were uniformly distributed on the three-dimensional carbon foam substrates coated with different amounts of graphene. The amount of graphene coating has a great influence on the hydrogen evolution performance. The composite prepared with a graphene concentration of 25 mg/L has the best electrochemical performance, its initial overpotential at a 10 mA cm-2 current density is 163 mV, and the corresponding Tafel slope is 76 mV dec-1. It has also the lowest impedance, which shows that coating the carbon foam with an appropriate amount of reduced graphene oxide accelerates electron migration and improves the hydrogen evolution performance.

     

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