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Facile Construction of Defect-rich Rhenium Disulfide/Graphite Carbon Nitride Heterojunction via Electrostatic Assembly for fast Charge Separation and Photoactivity Enhancement
摘要： Graphite carbon nitride (CN) is one of the most researched visible light photocatalysts, but it still cannot be used practically because of its low photoactivity resulting mainly from rapid photogenerated charge recombination. To accelerate charge separation, CN was herein electrostatically assembled with ReS2, a two-dimensional semiconductor to construct heterojunction for the first time. The electrostatic and coordination interactions between CN and defect-rich ReS2 make them close contact to form heterojunctions. The ReS2/CN heterojunction exhibits higher photocatalytic performance in pollutant degradation owing to faster generation of reactive oxygen species than CN, as well as increased visible and near-infrared light absorption because of strong photoabsorption of defect-rich ReS2. The accelerated reactive oxygen species generation for the heterojunction arises from accelerated charge separation, especially fast transfer of holes from CN to ReS2 in assistance of interfacial electric field and great valance-band edge difference. This work provides a novel CN-based heterojunction for photoactivity improvement and illustrates significance of electrostatic attraction in fabricating heterojunctions.
关键词： electrostatic interaction,photocatalytic,rhenium disulfide,graphite carbon nitride,charge separation
更新于2025-11-21 11:03:13
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Carbon quantum dots-decorated TiO2/g-C3N4 film electrode as a photoanode with improved photoelectrocatalytic performance for 1,4-dioxane degradation
摘要： In this study, carbon quantum dots (CQDs) were used to decorate a TiO2/g-C3N4 (TCN) film electrode. The morphological, optical, and electrochemical properties of the TiO2/g-C3N4/CQDs nanorod arrays (TCNC NRAs) film were investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and electro-impedance spectroscopy (EIS). The improved optical properties, photoelectrochemical chemical properties and photoelectrocatalytic (PEC) performance of photoanode can be observed by doping CQDs onto the TCN NRAs film. Compared with TiO2 NRAs and TCN NRAs, the narrower band gap of 2.47 eV and longer lifetime of photoinduced electron-hole pairs were observed in the TCNC NRAs. Under visible light irradiation and a bias voltage of 1.2 V, the photocurrent density and 1,4-dioxane (1,4-D) removal rate of PEC process with TCNC NRAs electrode reached 0.16 mA/cm2 and 77.9%, respectively, which was 2.5 times and 1.5 times of that with TCN NRAs electrode. TCNC NRAs electrode could keep >75% of the 1,4-D removal rate during five cycles tests. High PEC performance with TCNC NRAs electrode could be attributed to the enhanced charge separation and the change of electron transfer mechanism from typical heterojunction to Z-scheme, which may increase the active species production and change the dominant reactive species from O2?- to ?OH. Our experimental results should be useful for studying the degradation of 1,4-D and developing efficient PEC materials.
关键词： Graphite carbon nitride,TiO2 nanorods,1,4-Dioxane,Carbon quantum dots,Photoelectrocatalysis
更新于2025-09-23 15:21:01
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Carbon coated-Cu nanoparticles as a cocatalyst of g-C3N4 for enhanced photocatalytic H2 evolution activity under visible-light irradiation
摘要： The photocatalytic H2 evolution is an important technology to solve the energy crisis. The hydrogen evolution rate of the g-C3N4 system in triethanolamine solution as sacrificial agent is obvious higher than in methanol solution. But up to now, most of the Cu nanoparticles as cocatalyst of g-C3N4 photocatalytic systems for hydrogen evolution are performed in methanol solution because Cu nanoparticles are unstable in triethanolamine solution. Here, carbon coated-Cu nanoparticles as cocatalyst of g-C3N4 composites (Cu@C/g-C3N4) were prepared by simple two-steps technology of annealing then grinding. The compositions, morphology and optical and photoelectrochemical (PEC) properties of the composites were characterized by means of physicochemical techniques. The prepared composition was used to generate hydrogen under visible light irradiation in triethanolamine solution. The results displayed that the hydrogen evolution rate of the optimal Cu@C/g-C3N4 was up to 265.1 μmol g-1 h-1 that is close to the activity of 0.5% Pt/g-C3N4, and after four repeated reactions, the photocatalytic activity decreased only by about 15%. The good photocatalytic activity and stability result from Cu nanoparticles increase the transfer efficiency of charge carriers by trapping the photogenerated electrons produced by g-C3N4 and the protective effect of carbon layer on Cu nanoparticles.
关键词： Cu nanoparticles,Visible-light,Graphite carbon nitride,Photocatalytic H2 evolution,Carbon coating layer
更新于2025-09-23 15:21:01