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Synthesis of C3N4-decorated ZnO and Ag/ZnO nanoparticles via calcination of ZIF-8 and melamine for photocatalytic removal of methyl orange
摘要： The C3N4-decorated ZnO and Ag/ZnO nanoparticles were prepared using melamine and ZIF-8 as precursors after thermal treatment under air condition. The results from the structural analysis suggested that the presence of the metallic Ag as well as C3N4 in the composite and the introduction of the melamine could slightly enhance the aggregation of the particles of the three dimensional structure of ZnO and Ag/ZnO. However, the presence of C3N4 and Ag could boost the utilization of the light and increase the separation of electrons and holes. Finally, the photocatalytic degradation of methyl orange indicated that the C3N4-decorated ZnO and Ag/ZnO displayed an enhanced ability in comparison with pure ZnO and C3N4, which suggested that the synergistic effect of Ag and C3N4 played an important role in the catalytic process.
关键词： Photocatalytic degradation,ZIF-8,C3N4,Synergistic effect,Ag/ZnO composites
更新于2025-09-04 15:30:14
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Design of spatially separated Au and CoO dual cocatalysts on hollow TiO2 for enhanced photocatalytic activity towards the reduction of CO2 to CH4
摘要： Photocatalytic reduction of CO2 to solar fuels has been considered as a promising route to solve the energy crisis and environmental issues. Herein, the spatially separated CoO and Au dual cocatalysts are used as the hole and electron collectors, which are loaded on the internal and external surface of TiO2 hollow sphere (THS), respectively (denoted as Aux@THS@CoO). It is found that the Au nanoparticle and Co species are homogenous deposited on the surface of THS without doping. DRS results show that the photoabsorption performances of THS are enhanced obviously in the visible light region. XPS analysis reveals that an internal electric field is constructed, which could promote the separation of photoinduced charge carriers. Subsequently, Au2.0@THS@CoO displays the highest photocurrent density compared with the counterparts. Furthermore, the results of CO2 adsorption, ESR spectra and in-situ FTIR spectra show the high adsorption capacity of CO2 on the sample and the chemisorption of CO2 on the oxygen defects of THS conversed into the active intermediate CO2-. As a result, Au2.0@THS@CoO presents a remarkably enhanced photocatalytic activity for the reduction of CO2 with H2O in CH4. The optimal activity of the catalyst is 13.3 μmol h-1 g-1, which is 60 times higher than that of THS. In addition, in-situ FTIR spectra also suggest that H2O participates in the reaction as electron donator and hole scavenger during the photocatalysis process. Finally, a possible photocatalytic process has also been proposed.
关键词： Photocatalysis,Synergistic effect,Spatial separation,Dual cocatalysts,CO2 reduction
更新于2025-09-04 15:30:14