Comparison of modulation strategies for enhancing the photocatalytic water splitting performance of metal-organic frameworks

Metal-organic framework materials (MOFs) have proven to be an excellent catalyst, but how to further improve their photocatalytic performance has become a challenge for researchers. In this study, we focus on the effect of two modulation strategies on the photocatalytic performance of MOFs, and 2-mercaptobenzimidazole (MBI) was introduced into the ZIF-67 structure by the solvent-assisted ligand exchange (SALE) method and the mixed ligand method, respectively, to modulate their photocatalytic performance. It was found that both strategies can suc-cessfully introduce MBI into the ZIF-67 structure, but the mixed ligand method tends to destroy the crystal morphology and structure of ZIF-67 and constructs a good deal of mesopores in the structure, which is detri-mental to the improvement of catalytic performance. On the contrary, the SALE strategy can maintain the special crystal morphology and structure of ZIF-67 while introducing MBI, and can construct a suitable number of de-fects to enhance the photogenerated carrier transfer and separation efficiency of ZIF-67. Under the action of visible light, the ZIF-67-MBI catalysts obtained by the SALE method have the optimal photocatalytic activity, and their photocatalytic hydrogen and oxygen evolution rates can reach 6.14 mmol g-1 h-1 and 210 mmol g-1 h-1, respectively. This study demonstrates that the SALE method is a viable strategy to modulate the photo -catalytic performance of MOFs and provides a reference for the construction of composites with excellent photocatalytic properties.