A Mo doping WO3/CdZnS heterojunction photoelectrode for boosting electron storage capacity

Most of the photoelectrodes for photoelectrochemical cathodic protection (PECCP) technology reported at present cannot store electrons, leading to the inability to protect metals in the absence of light, which becomes the main defect that limits the practical application of PECCP. In this work, a Mo doping WO3/CdZnS heterojunction photoelectrode with electrons storage capability was prepared, by which the PECCP can be kept running in the absence of light. The result of theoretical calculation of density functional validates that Mo doping can introduce new doping levels into WO3, leading to modifications in the intrinsic electronic structure associated with increasing capacitance and conductivity. The compounding of CdZnS can not only broaden the light absorption threshold of the photoelectrode, but also charge the Mo-WO3. Besides, the construction of heterojunction also facilitates the oriented separation and migration of photogenerated carriers. The 0.3%Mo-WO3/CdZnS-2 composite photoelectrode with desirable capacity of electron storage can store the quantity of electric charge about 1.87 × 10−3 C after 100 s illumination, which is about 1.5 times of WO3/CdZnS-2 without Mo doping. In the meanwhile, the persistent PECCP performance in the absence of light was also prolonged from 481 s to 584 s.