Hydrogen evolution using a self-supported starch carbon aerogel electrocatalyst loaded with CeO2–MoxC in alkaline saline water†

Hydrogen is a vital source of clean energy, which has gradually emerged as a prominent research topic. Design and development of active, stable, and low-cost electrocatalysts are essential prerequisites for achieving large-scale hydrogen production. In this study, a cost-effective, high-performance hydrogen evolution catalyst was developed by creating a porous carbon aerogel (CeO₂–Mo_xC/PSCA) using starch and molybdenum salts, followed by the addition of CeO₂ through a hydrothermal method. Detailed analyses using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) confirmed that nitrogen doping generated additional defects on the carbon surface, thereby enhancing the active sites for hydrogen evolution. The incorporation of CeO₂ improved the conductivity and hydrolysis ionization resulting in optimization of ΔGH*. The electrochemical test results revealed that in 1.0 M KOH, a current density of 10 mA cm⁻² corresponded to an overpotential of 63 mV and a Tafel slope of 24.6 mV dec⁻¹. In 1.0 M KOH + 0.5 M NaCl, at a current density of 10 mA cm⁻², the overpotential increased to 79 mV, and the Tafel slope decreased to 21.4 mV dec⁻¹. These results suggest that CeO₂–Mo_xC/PSCA-3-900 exhibits excellent catalytic performance in both alkaline and alkaline saline solutions.