Citric Acid-Derived Nanoporous Molybdenum Carbide Electrocatalyst for HER: Effect of Porosity on HER Performance

The development of noble metal-free electrocatalyst for HER is crucial for sustainable green electrolytic hydrogen production. Molybdenum carbides have shown enormous potential as an economic electrocatalyst for HER. In this study, we have synthesized three Mo2C/C electrocatalysts by varying the ratios of carbon (citric acid) and molybdenum (ammonium heptamolybdate) precursors as 2:1, 1:1, and 1:2 (samples abbreviated as CAMO21, CAMO11, and CAMO12) using the carburization method. The synthesized samples are characterized by powder XRD, Raman spectroscopy, SAXS, SEM, and TEM which revealed the crystal phase, porosity, and morphological properties of the samples. The polarization curves reveal that their electrochemical activity for HER varied as CAMO12 > CAMO11 > CAMO21. EIS studies indicated that the resistance due to porosity of the samples is maximum for CAMO11, indicating that a bimodal porosity with a substantial fraction of pores near the micropore region is not beneficial for electrochemical HER.