(621f) Kinetic Study for the Hydrogen Production Via Water-Splitting of Ascorbic Acid with a CdS-ZnS/Pt Binary Photocatalyst

Water splitting via solar energy to generate hydrogen represents a promising energy resource to address the emission and the environmental climate change. Cadmium Sulfide (CdS), with its specific characteristics, attracts significant attention as a promising photocatalyst for water splitting. However, most experimental studies do not provide adequate data to perform kinetic studies and develop kinetic models that are necessary for reactor and process design. Therefore, in this study, the binary photocatalyst CdS-ZnS/Pt was employed for water splitting using simulated solar energy to produce Hydrogen. In addition, it was necessary to design and fabricate a fully automated experimental lab-apparatus (cylindrical reactor with 70 mm ID and 10 mm depth; top-down illumination) to conduct unattended and long-duration experiments while collecting data continuously. At first, the crystallinity of the catalyst, the particle size distribution of the particles, and the band gap of the catalyst were checked given their critical role in the hydrogen evolution rate. The XRD results verified the hexagonal structure (of CdS), the FESEM images showed particles’ size from 150 nm to 2 µm, and the solid state UV-Vis yielded a band gap of 2.3 eV. Toward the collection of the kinetic data, various ranges of the catalyst loading, the concentration of the sacrificial reagent, the temperature, and the light intensity were studied. In parallel, the photo-deposition of Pt cocatalyst proved as another critical factor; herein conducted for 30 min under 1-sun intensity. The so far data showed that the optimum hydrogen evolution rate at one-sun is 260 µmol/h or (6,500 µmol/g.h) at 40ᴼC and 1.0 M ascorbic acid. At completion, the experimental dataset will be one of the few appropriate ones for kinetic studies’ and comprehensive design of photocatalytic reactors.