Scalable polycondensation approach for efficient Al/S@g-C₃N₄ hydrogen production catalyst

This article investigates the development of an efficient Al/S@g-C₃N₄ catalyst for hydrogen production through sodium borohydride (NaBH₄) methanolysis. The catalyst was prepared using a facile and scalable polycondensation technique. The prepared catalyst was characterized extensively by XRD, FTIR, SEM, and surface area analyses. XRD and FTIR analysis showed a reduction in the interlayer distance between the S@g-C₃N₄ sheets with increasing Al content. The SEM images showed a rough and uneven surface of the nanosheets. The obtained values of E_g are 2.6, 2.4 and 2.5 eV for the samples doped with 0.0, 1.0 and 2.0 wt% of Al. Increased surface area (up to 92 m²/g) and slightly smaller mesopores (1.56 nm) observed with increasing Al doping up to 2.0 wt%. Significant enhancement in hydrogen generation rate with a maximum of 10,112 mL/g.min was achieved for 2.0 wt% Al. Low activation energy of 27.08 kJ/mol for the 2.0 wt% Al-doped catalyst. The catalyst demonstrated good stability after undergoing multiple NaBH₄ methanolysis cycles.