Charge-transfer regulated visible light driven photocatalytic H2 production and CO2 reduction in tetrathiafulvalene based coordination polymer gel

The much-needed renewable alternatives to fossil fuel can be achieved efficiently and sustainably by converting solar energy to fuels via hydrogen generation from water or CO 2 reduction. Herein, a soft processable metal-organic hybrid material is developed and studied for photocatalytic activity towards H 2 production and CO 2 reduction to CO and CH 4 under visible light as well as direct sunlight irradiation. A tetrapodal low molecular weight gelator (LMWG) is synthesized by integrating tetrathiafulvalene (TTF) and terpyridine (TPY) derivatives through amide linkages and results in TPY-TTF LMWG. The TPY-TTF LMWG acts as a linker, and self-assembly of this gelator molecules with Zn II ions results in a coordination polymer gel (CPG); Zn-TPY-TTF. The Zn-TPY-TTF CPG shows high photocatalytic activity towards H 2 production (530 μmol g −1 h −1 ) and CO 2 reduction to CO (438 μmol g −1 h −1 , selectivity > 99%) regulated by charge-transfer interactions. Furthermore, in situ stabilization of Pt nanoparticles on CPG (Pt@Zn-TPY-TTF) enhances H 2 evolution (14727 μmol g −1 h −1 ). Importantly, Pt@Zn-TPY-TTF CPG produces CH 4 (292 μmol g −1 h −1 , selectivity > 97%) as CO 2 reduction product instead of CO. The real-time CO 2 reduction reaction is monitored by in situ DRIFT study, and the plausible mechanism is derived computationally. Designing active materials for efficient photocatalysis are of great interests. Herein the authors report coordination polymer gel assembled by low molecular weight gelator as photocatalysts for visible light driven H 2 production and CO 2 reduction regulated by charge-transfer interactions.