Facile Hydrothermally Synthesized a Novel CdS Nanoflower/Rutile-TiO₂ Nanorod Heterojunction Photoanode Used for Photoelectrocatalytic Hydrogen Generation

With the application of ethylenediamine (EDA) as a solvent, a template, and co-ordination agents, novel photoanode architecture of the cadmium sulfide (CdS) nanoflower (NF)/rutile(R)-TiO₂ nanorod (NR) heterojunction is successfully synthesized using a facile two-step hydrothermal process. The optimized CdS (medium concentration; MC) NF/R-TiO₂ NR heterojunction exhibited a greatly enhanced visible-light photoelectrochemical (PEC) performance, whereby the highest photocurrent density of 3.23 mA cm^-2 at 0.1 V versus Ag/AgCl and a photoconversion efficiency (PCE) of 0.46% were achieved under solar light irradiation. The optimal photocurrent density of the CdS (MC) NF/R-TiO₂ NR heterojunction, photoanode is 2.54 times (60.68%) higher than that of the pristine R-TiO₂ NR because of an effective light absorption, an appropriate band-edge position, and the charge separation. Furthermore, the open circuit voltage (V_OC) was shifted from -0.85 V to -1.34 V due to the grafting of the CdS NF onto the R-TiO₂ NR facet; this surface modification reveals the synergistic effect. The optimal CdS (MC) NF/R-TiO₂ NR heterojunction showed a PEC hydrogen (H₂) generation of 1007.98 μmol after 3 h. The design of the novel heterojunction photoanode that is proposed in the present strategy can shed light on the fabrication of new, cheap photocatalysts for an effective H₂ generation.