Synthesis and characterization of CdS/MIL-125 (Ti) as a photocatalyst for water splitting

Titanium based metal organic framework MIL-125 was incorporated with narrow band-gap semiconductor CdS through a solvothermal approach. Samples with different amounts of CdS loading were prepared and characterized using ICP, N-2-physisorption, PXRD, DRS, SEM, TEM, HRTEM, STEM and EDS methods. The resulting composites were tested for photocatalytic hydrogen production through water splitting with platinum and lactic acid as co-catalyst and sacrificial agent, respectively. The optimized sample (with about 8 wt% CdS) showed 2.8 times higher activity compared to bulk CdS and retained its integrity through both long-term and recycling experiments. As an attempt to further elucidate the mechanism of photocatalytic activity enhancement, CdS/SBA-15 composite was investigated. Both CdS and MIL-125 proved to be active under irradiation but electron injection from CdS to MIL-125 is most likely to be the main mechanism for suppressing charge carrier recombination and also prohibiting photo-corrosion.