Decipher of the structure and surface chemistry in molybdenum phosphosulfide on electrochemical catalytic hydrogen evolution reaction

Abstract

It has been a fascinating and significant topic that how the chemical composition and surface structure of nanomaterials govern the catalytic performance. In this paper, we deliberately design molybdenum phosphosulfide nanoparticles anchored on the carbon nanotubes (CNTs) and systematically study the correlation between structure/surface composition and the electrochemical hydrogen evolution reaction (HER) activity and stability. We discover that the HER activities show significant enhancement with the incorporation of P in the molybdenum disulfide structure (MoS2|P/CNT) or S in the molybdenum phosphide structure (MoP|S/CNT). The stability of the MoS2|P/CNT catalyst exhibits high stability which is consistent with the pristine MoS2/CNT, while the stability of the MoP/CNT sample is enhanced after the introduction of the S element. The density function theory (DFT) results indicate that the doped P atoms in the MoS2 structure provide more enhanced active sites, leading to promoted HER activity. For the MoP|S/CNT samples, the doped S site is calculated to be less active for HER yet can greatly enhance P site to present better activity. The anion doping effect unveiled here provides insights into molybdenum phosphosulfides for HER and may also be expanded to broad catalyst design for energy related applications.