Bimetallic Fe-Mo sulfide/carbon nanocomposites derived from phosphomolybdic acid encapsulated in MOF for efficient hydrogen generation

Abstract

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record ; To tackle the energy crisis and achieve a more sustainable development, hydrogen as a clean and renewable energy resource has attracted great interest. Searching for cheap but efficient catalysts for hydrogen production from water splitting is urgently needed. In this report, bimetallic Fe-Mo sulfide/carbon nanocomposites that derived from a polyoxometalate phosphomolybdic acid encapsulated in metal organic framework MIL-100 (PMA@MIL-100) have been generated and their applications in electrocatalytic hydrogen generation were explored. The PMA@MIL-100 precursor is formed via a simple one-pot hydrothermal synthesis method and the bimetallic Fe-Mo sulfide/carbon nanocomposites were obtained by chemical vapour sulfurization of PMA@MIL-100 at high temperatures. The nanocomposite samples were fully characterized by a series of techniques including XRD, FT-IR, TGA, N2 gas sorption, SEM, TEM, XPS, and were further investigated as electrocatalysts for hydrogen production from water splitting. The hydrogen production activity of the best performed bimetallic Fe-Mo sulfide/carbon nanocomposite exhibits an overpotential of -0.321 V at 10 mA cm-2 and a Tafel slope of 62 mV dec-1 with a 53% reduction in overpotential compared to Mo-free counterpart composite. This dramatic improvement in catalytic performance of the FeMo sulfide/carbon composite is attributed to the homogeneous distribution of the nanosized iron sulfide, MoS2 particles and the formation Fe-Mo-S phases in the S-doped porous carbon matrix. This work has demonstrated a potential approach to fabricate complex heterogeneous catalytic materials for different applications. ; Engineering and Physical Sciences Research Council (EPSRC) ; Leverhulme Trust ; European Union