Coupled Biphase (1T-2H)-MoSe₂ on Mold Spore Carbon for Advanced Hydrogen Evolution Reaction

Performance breakthrough of MoSe₂-based hydrogen evolution reaction (HER) electrocatalysts largely relies on sophisticated phase modulation and judicious innovation on conductive matrix/support. In this work the controllable synthesis of phosphate ion (PO₄³⁻) intercalation induced-MoSe₂ (P-MoSe₂) nanosheets on N-doped mold spore carbon (N-MSC) forming P-MoSe₂/N-MSC composite electrocatalysts is realized. Impressively, a novel conductive N-MSC matrix is constructed by a facile mold fermentation method. Furthermore, the phase of MoSe₂ can be modulated by a simple phosphorization strategy to realize the conversion from 2H-MoSe₂ to 1T-MoSe₂ to produce biphase-coexisted (1T-2H)-MoSe₂ by PO₄^3- intercalation (namely, P-MoSe₂), confirmed by synchrotron radiation technology and spherical aberration-corrected TEM (SACTEM). Notably, higher conductivity, lower bandgap and adsorption energy of H⁺ are verified for the P-MoSe₂/N-MSC with the help of density functional theory (DFT) calculation. Benefiting from these unique advantages, the P-MoSe₂/N-MSC composites show superior HER performance with a low Tafel slope (≈51 mV dec^-1) and overpotential (≈126 mV at 10 mA cm^-1) and excellent electrochemical stability, better than 2H-MoSe₂/N-MSC and MoSe₂/carbon nanosphere (MoSe₂/CNS) counterparts. This work demonstrates a new kind of carbon material via biological cultivation, and simultaneously unravels the phase transformation mechanism of MoSe₂ by PO₄^3- intercalation.