2D/2D/2D O-C3N4/Bt/Ti3C2Tx heterojunction with novel MXene/clay multi-electron mediator for stimulating photo-induced CO2 reforming to CO and CH4

Controlled fabrication of Ti3C2 MXene with unique topology and layered bentonite (Bt) nanoclay to construct a 2D/2D/2D g-C3N4/Bt/Ti3C2 MXene heterojunction for intriguing photocatalytic CO2 reduction has been investigated. The MXene/Bt composite exhibits high-light absorption and faster charges separation and transportation. The photoactivity of 2D/2D Ti3C2/g-C3N4 of 1.38 folds higher than bulk Ti3AlC2/g-C3N4 obtained due to intimate interface interaction with proficient charges separation. The highest g-C3N4/Bt/Ti3C2 heterojunction activity for CH4 evolution of 4.18, 4.42 and 6.96 folds more was achieved compared with g-C3N4/Ti3C3, Bt/g-C3N4 and g-C3N4, respectively. This boosted activity was evidently due to Ti3C2/g-C3N4 Schottky junction with Bt-mediator to provide new electron transfer channels. More interestingly, with proton rich acetic-acid reagent, 4.15 folds more CH4 production than using only water under prolonged stability was observed. Thus, this study provides a promising approach for clean energy system and potential applications of MXenes/Bt materials for solar fuels production.