Photocatalytic water splitting over titanium aluminium carbide assisted ruthenium with graphitic carbon nitride for hydrogen production

Abstract

Photocatalytic water splitting for hydrogen production is considered to solve the issue of greenhouse gases and other environmental concerns as hydrogen is considered as an alternative source of energy that can replace fossil fuel. The objective of this study is to develop ternary photocatalyst functional under visible light for water splitting to generate hydrogen. Titanium aluminium carbide (Ti3AlC2) dispersed ruthenium (Ru) doped graphitic carbon nitride (g-C3N4) composite (Ti3AlC2/Ru/g-C3N4) was developed using hydrothermal assisted impregnation method followed by characterization including XRD, SEM, TEM, Raman, UV-visible and PL spectroscopy techniques. The function of g-C3N4 is to enhance visible light harvesting, while Ti3AlC2 developed Z-scheme hetero-junction for fast charges separation as a result more electrons were produced for H+ to H2 reaction. The photocatalytic activity was tested using slurry photo-reactor systems for continuous H2 production. Ti3AlC2/Ru/g-C3N4 composite was observed to produce 1665 µmolg-1h-1 of H2 with each gave 1.3 and 1.93 times higher than produced from Ru/g-C3N4 and Ti3AlC2/g-C3N4 samples, respectively. This enhanced hydrogen production was obviously due to superior photogenerated charges separation with higher visible light absorption and developing Z-scheme heterojunction. The operating parameters such as varying catalyst loading, various sacrificial reagents and irradiation time were investigated. Besides, the stability of catalyst over 3 continuous cycles was also studied. The highest yield rate of hydrogen production was for 0.25 g catalyst loading. H2 production by using different sacrificial reagents was in order: water < glycerol < ethanol < ethylene glycol < methanol. In conclusion, excellent performance of composite catalyst using a slurry reactor for H2 production would offer a new opportunity of developing structured photocatalysts for renewable fuels production under visible light.