Novel AgI/Ag2Mo2O7 heterojunctions were prepared by reacting Ag2Mo2O7 microrods with an aqueous KI solution at room temperature. The composite materials, compared with neat AgI and Ag2Mo2O7, showed much higher activities in the photocatalytic degradation of aqueous rhodamine B, methyl orange, tetracycline hydrochloride, and levofloxacin solutions under visible-light irradiation. The structures, morphologies, and other physicochemical properties of AgI, Ag2Mo2O7, and AgI/Ag2Mo2O7 composites were studied via various characterization techniques. The active species involved in the photocatalytic process were examined via radical-capturing experiments and electron spin resonance. Superoxide anion radicals (•O2–) and photogenerated holes (h+) were found to be the main active species. Photocatalytic mechanisms were proposed and reasons for the enhanced photocatalytic activity were explained.
Zhenlu Liu,Jing Xu,Jiandong Wu,Ye Liu,Lijun Ma,Linying Hu
Photocatalysis is one of the most promising methods to solve the problems of solar energy conversion and sustainable fuel production. Among them, the semiconductor electronic transition to produce hydrogen is the most critical research topic in the field of photocatalysis. ZnS and Ag2Mo2O7 monomers were prepared by the hydrothermal method. The S-scheme heterojunction was formed by electrostatic adsorption of the two materials. The S-scheme heterojunction can improve the separation rate of photogenerated carriers through the built-in electric field so that the hydrogen production rate of the system can reach a maximum of 871.9 μmol g−1 h−1. The system showed a good photoelectric response according to UV-Vis DRS and electrochemistry studies and excellent hydrogen evolution performance. In this study a DFT simulation of the heterojunction interface formed by the system was also carried out, and the relative size of the surface work function indicated the transfer direction and path of electrons.
Jing Wang,Peng Guo,Maofeng Dou,Jing Wang,Yajuan Cheng,Pär G. Jönsson,Zhe Zhao
The g-C3N4/m-Ag2Mo2O7 composite photocatalysts with well-aligned band structures are successfully fabricated by a simple two-step method with different mass contents of m-Ag2Mo2O7. The as-prepared samples are evaluated as photocatalysts toward rhodamine B (RhB) degradation in aqueous solution under visible light irradiation (λ > 420 nm). The results demonstrate that the photocatalytic activities of the composites are strongly influenced by the weight ratio of g-C3N4 to m-Ag2Mo2O7. When it is 6 : 1, the composite exhibits the highest photocatalytic efficiency. More specifically, this value is as high as 3.4 and 6.1 times that of pure g-C3N4 and P25 respectively. In order to investigate the mechanism causing the enhanced photocatalytic degradation, the band structures are determined by UV-vis diffuse reflection spectroscopy and the Mott–Schottky technique. Moreover, the reactive radicals involved in the photocatalytic process are examined in detail via active species trapping (AST) experiments. The improved photocatalytic activities can be attributed to the efficient separation of the photo-induced charge carriers and the strong redox capacities benefit from the synergetic effect between g-C3N4 and m-Ag2Mo2O7.
Although lithium–oxygen batteries (LOBs) hold great promise as future energy storage systems, they are impeded by insulated discharge product Li 2 O 2 and sluggish oxygen reduction reaction/oxygen evolution revolution (ORR/OER) kinetics. The application of a highly efficient cathode catalyst determines the LOBs performance. The d-band modulation and catalytic kinetics promotion are important concept guidelines for the performance enhancement of cathode catalysts. In this work, the homogeneous in-plane distortion-derived synergistic catalytic capability of an Ag 2 Mo 2 O 7 catalyst with modulated d-band centers and promoted ORR/OER kinetics is demontrated. The uniform elongation of Ag─O bonds and compression of Mo─O bonds in (020) plane leads to d-band splitting and d-band center optimization and delivers improved adsorption behavior for high ORR/OER capability. Furthermore, the spatial and energy overlap of Ag d xz and O 2 anti-bonding π * orbitals facilitate electron injection during ORR process and reduce the energy barrier for charge transfer and O 2 desorption during OER process, accelerating the ORR/OER kinetics. As a result, the (020) plane-exposed Ag 2 Mo 2 O 7 cathode exhibits ultralong cycle stability of 817 cycles at 500 mA g −1 and large specific discharge/charge capacities of 15898/15180 mAh g −1 . This work provides facile concept guidance for optimizing catalytic capability through controlled lattice distortion in cathode catalysts for LOBs.
危险品化学品经营许可证（带存储）