Enhancement of photocatalytic efficiency of Fe2O3 through g-C3N4 nanosheet modification for degradation of organic and pharmaceutical pollutants and hydrogen production

In this paper, a Fe2O3/g-C3N4 nanocomposite was prepared using a facile precipitation method, demonstrating the influence of g-C3N4 nanosheets on the photocatalytic efficiency of alpha-Fe2O3. Despite the stability of pure g-C3N4 during heat treatment up to 700 degrees C, its presence, along with iron oxide during calcination, reduces its stability temperature to about 450 degrees C. The reduction of hematite to magnetite by carbon is accompanied by the decomposition of g-C3N4. The appropriate calcination temperature determined for this synthesis process is 390 degrees C. Microscopic analysis revealed a uniform distribution of alpha-Fe2O3 particles (average particle size of 16 nm) on g-C3N4 nanosheets with a close and intimate contact. The g-C3N4 content in the nanocomposite influenced the size of Fe2O3 nanoparticles. g-C3N4 nanosheets in the alpha-Fe2O3 structure changed the band gap from 1.9 to 2.4 eV, reducing the recombination rate of electrons and holes. A nanocomposite containing 10 wt% g-C3N4 showed the highest photocatalytic performance. The Z-scheme charge transfer mechanism and the significant role of superoxide radicals in the photocatalytic process were identified. The nanocomposite's photocatalytic efficiency was evaluated on various pollutants, including methylene blue (MB, 88 %), phenol (60 %), methyl orange (MO, 38 %), and the pharmaceutical compound Metformin (96 %). The alpha-Fe2O3/10 wt% g-C3N4 nanocomposite exhibited the highest hydrogen production rate at 435 mu mol/g.h, establishing its importance in photocatalytic performance.