Molybdenum disulfide supported on chitin carbon aerogels as an efficient and stable hydrogen evolution electrocatalyst

Chitin carbon aerogel (CCA) was prepared from chitin in this work, which exhibits a highly porous fibrous network structure and a large specific surface area (SSA). Molybdenum disulfide (MoS₂) nanosheets were synthesized on CCA (MoS₂-CCA) by a hydrothermal method. The unique structure of CCA prevents the aggregation of MoS₂ and increases its SSA, thereby exposing more catalytic active sites. The catalytic performance of MoS₂-CCA for the hydrogen evolution reaction (HER) was investigated, and it was found that its catalytic activity significantly outperforms that of MoS₂ supported on chitin carbon (MoS₂-CC), commercial MoS₂, and homemade MoS₂, with a low onset overpotential (151 mV) and good cycling stability. According to the analyses for structure, morphology, surface properties, and element valence states, besides the large SSA and porous structure of CCA, the rich oxygen and nitrogen-containing functional groups in CCA are also useful to the excellent catalytic activity, which increase the content of low-valence Mo and S. The synthesis strategy described herein is simple, and the biomass chitin used is a naturally occurring marine polymer that is inexpensive and non-polluting. This approach offers new avenues for designing high-efficiency HER electrocatalysts.