Controllable green synthesis of crassula peforata-like TiO2 with high photocatalytic activity based on deep eutectic solvent (DES)

TiO2 as an important photocatalyst, how to achieve its fast, controllable and green synthesis still remains a big challenge for the large-scale preparation and application. Deep eutectic solvents (DESs) are promising solvents in the green and mild preparation of high active nanomaterial due to their low cost, high green degree, low toxicity, easy large-scale preparation and similar properties with conventional ionic liquids. In this study, through the combined effect of both H-bond donor and H-bond acceptor, we have successfully used DES as solvent, template and inhibitor at the same time to fast synthesize new crassula peforata-like TiO2 with (0 0 1) and (1 0 1) planes under mild reaction conditions (at 160 °C for only 4-8 h). The H2 production rate by photocatalytic water splitting of this catalyst reaches up to 13.13 mmol·h−1·g−1, which is 18-fold greater than that of commercial P25 TiO2 and also much higher than those of other TiO2 nanostructures. Such rate is the highest yield reported so far to the best of our knowledge for photocatalytic H2 production catalyzed by sole TiO2. The higher activity is attributed to the special shape with surface heterojunctions and defects. This study will provide a new way for the green, fast, easy-controllable and batch preparation of new and high efficiency photocatalysts.