Photocatalytic degradation of methanol-water in presence of g-C3N4 and graphene/g-C3N4.

Photocatalytic production of H2 from the decomposition of water has attracted increased attention, as the environmental damages caused by the rapid evolution of industry are threatening the development of human society. This energy production is considered a green and eco-friendly resource. It has the potential to replace the carbon component of fuelling the society; on the other hand allows for the limitation of greenhouse gas emissions, thereby mitigating the worsening of climate change. While titanium dioxide is widely used in the photocatalytic field, its yield is still low due to the fast recombination of the photo-generated charge carriers. Graphitic carbon nitride (g-C3N4) possessing high thermal and chemical stability, non-toxicity and low band gap energy is a promising candidate for photocatalytic applications. In this study the exfoliation of the bulk g-C3N4 made with melamine was synthesised via a chemical approach using nitric acid at room temperature, in order to get prolonged carrier lifetime. Moreover the surface of bulk g-C3N4 made with melamine and urea and the exfoliated g-C3N4 made with melamine was modified with graphene (0.5 wt% and 1 wt%). Hydrogen generation from methanol/water mix proved that only hydrogen was produced in the unmodified bulk and exfoliated g-C3N4 , while H2, CH4 and CO have been generated in the modified specimens with graphene. This was assigned to the increased spatial charge carrier separation conducted by graphene.