Heterostructural TiO2/Ti3C2 MXene aerogel composite for photocatalytic degradation of palm oil mill effluent

Abstract

The design of effective POME treatment is crucial to mitigate the waste production of the palm oil industry. Against this backdrop, the use of TiO2 based photocatalytic degradation technology for POME degradation is of viable interest due to the possibility of total organic substrate oxidation. Herein, a heterostructural aerogel composite comprising {001}-TiO2 and Ti3C2 MXene aerogel was synthesised to investigate its POME photodegradation efficiency. POME degradation was done under black light irradiation and without external oxygen bubbling to mimic the photodegradation process under natural ponding conditions. Characterisation results showed an increase in the surface roughness and porosity of the Ti3C2 aerogel structure which enhanced its contact with TiO2 leading to the formation of interfacial heterojunctions. With the synergy of Schottky-junction hole trapping and exposed active {001} TiO2 facets arising from the interfacial heterojunction, the composite was reported to have a POME degradation efficiency of 98.3% over 24 h which is higher as compared with that of the Ti3C2 aerogel (73.7%) and TiO2 (58.9%). The improved electron–hole separation and active facet exposure of the TiO2/ Ti3C2 heterostructure indicate the potential applications of two-dimensional transition metal carbides for waste treatments via photocatalysis.