Li Ji,Wang Yanhong,Tian Yiyuan,He Xuan,Yang Pingping,Yuan Minghui,Cao Yuqing,Lyu Jinze
The photocatalytic mineralization efficiency of volatile organic compounds (VOCs) is determined by adsorption of reactants, separation of charge carriers, and reaction activity of catalyst surface. Herein, we provide a strategy to synthesize a novel catalyst, namely, PhPt-Micro, which is characterized by high adsorption ability, charge separation efficiency, and surface reaction activity. Toluene was chosen as the model VOC. The effects of photochemical deposition of Pt on the physical properties of microporous amorphous TiO 2 (Micro) and toluene mineralization were studied using N 2 adsorption/desorption, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, GC-flame ionization detection, and surface photovoltage spectroscopy (SPS) analyses. After photochemical treatment, the structure of Micro was optimized, and Pt nanoparticles were successfully deposited at the outlet of electrons on the catalyst surface. SPS result proved that the optimized structure enhanced the separation efficiency of charge carriers and the migration of photo-generated electrons to the PhPt-Micro surface. The quasi-equilibrium adsorption amount of toluene over PhPt-Micro was two times higher than that with commercial nano TiO 2 (P25). The micropores concentrated toluene on the catalyst surface and hindered intermediate desorption. The mineralization efficiency of toluene over PhPt-Micro was 2.4 and 5.9 times higher than those over Micro and P25, respectively.
Jianming Fan,Jinhua Xiong,Dayue Liu,Yuanping Tang,Song He,Zhibiao Hu
A novel strategy was developed to fabricate a CdS/Pt photocatalyst (defined as CdS/w%Pt-PAR) via the cathodic photocorrosion effect of CdS. A tentative mechanism for Pt deposition on CdS via the cathodic photocorrosion effect was proposed, based on a series of electrochemical characterization methods, such as cyclic voltammetry and Mott-Schottky tests. Transmission electron microscopy verified that Pt was grafted on the CdS surface via a heterojunction. Moreover, a strong interaction between Pt and CdS was further confirmed by X-ray photoelectron spectroscopy. The optimal photocatalytic H2 evolution rate of CdS/2%Pt-PAR was 1086.1 μmol h−1, 6.4 and 2.6 fold higher than that of the reference samples synthesized by traditional photodeposition (CdS/2%Pt-PD) and chemical reduction (CdS/2%Pt-CR) methods, respectively. Linear sweep voltammetry and fluorescence experiments verified that CdS/2%Pt-PAR has a lower H2 evolution overpotential and faster separation of photogenerated carriers, respectively, compared with CdS/2%Pt-PD and CdS/2%Pt-CR. This work paves a new route for fabricating CdS/metal photocatalysts with highly efficient and stable photocatalytic H2 evolution activity.
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