Applied Catalysis B: Environmental, Vol.232, 481-491, 2018
Fabrication of novel all-solid-state Z-scheme heterojunctions of 3DOM-WO3/Pt coated by mono-or few-layered WS2 for efficient photocatalytic decomposition performance in Vis-NIR region
In this work, novel three dimensional ordered macroporous (3DOM) WO3/Pt/WS2 all-solid-state Z-scheme heterojunctions were firstly synthesized by gas phase chemical reduction methods. The layer numbers of coated WS2 on the skeleton of 3DOM Z-scheme heterojunctions are easily tuned by controlling the amount of sulfur powder, and the energy band structure of WS2 can be thus artificial turned, leading to distinct visible and near infrared (Vis-NIR) light absorption and charge separation ability of the as-prepared 3DOM samples. The experimental results show that the obtained 3DOM-WO3/Pt sample coated by 2-3 layered WS2 exhibits high photoelectric conversion ability, unbelievable photocurrent signal and excellent photodegradation activity, suggesting that the high separation efficiency of photon-generated charge can result in the superior photo catalytic performance of 3DOM-WO3/Pt/WS2. The selective photo-deposition of Au is used to proof the possible mechanism of charges transfer, and the results show that Z-scheme heterojunction can endow 3DOM-WO3/Pt/WS2 sample with a unique charges migration path, in which the photogenerated electrons on the conduction band (CB) of WO3 and the holes on the valence band (VB) of WS2 are easily transferred into metal Pt to recombine and the lifetime of electrons on the CB of WS2 as well as the holes on the VB of WO3 are strongly prolonged.
Keywords:3DOM;Z-scheme heterojunction;Mono-or few-layered WS2;Gas phase chemical reduction;Wastewater purification