Enhanced activity of Co–Mo–S catalysts towards hydrodesulfurization and hydrogen evolution reaction via NaBH4 assisted formation

Abstract

Co–Mo–S based catalysts have promising applications in both the hydrogen evolution reaction (HER) and hydrodesulfurization (HDS). Herein, Co–Mo–S catalyst and Co–Mo–S catalyst with and without NaBH₄ modification have been successfully synthesized by a simple hydrothermal synthesis method. Co–Mo–S catalysts with NaBH₄ modification show better catalytic activity towards both HDS and the HER. The phase purity, morphology, crystal structures and electron valence distribution of the catalysts with and without NaBH₄ modification were studied by experimental characterizations and theoretical calculations. The catalysts without NaBH₄ modification are mostly 2H-MoS₂, while the catalysts without NaBH₄ modification have 1T-MoS₂, and 1T-MoS₂ is exposed to more active sites, which will be conducive to the results of HDS performance of the catalyst. DFT calculations investigated the required activation energies of 1T-MoS₂ and 2H-MoS₂ for HDS and HER, respectively. The activation energy required for both HDS and H₂ generation of 1T-MoS₂ is significantly lower than that for the 2H-MoS₂ structure.