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Enhanced photocatalytic activity of g-C3N4 quantum dots/Bi3.64Mo0.36O6.55 nanospheres composites
摘要： In this research, heterostructured g-C3N4 quantum dots (CNQDs)/Bi3.64Mo0.36O6.55 nanospheres have been fabricated trough an in situ precipitation process. Compared to the pure Bi3.64Mo0.36O6.55, the as-fabricated CNQDs/Bi3.64Mo0.36O6.55 nanocomposites exhibited significantly improved photocatalytic performance for the photodegradation of rhodamine B (Rh B) and bisphenol A (BPA). In addition, 5 wt% CNQDs/Bi3.64Mo0.36O6.55 sample showed the highest photocatalytic efficiency under visible-light irradiation (λ > 420 nm). The effective separation and transmission of photogenerated electron-hole pairs caused by CNQD loading as well as the improved BET surface area are associated with the enhancement of the photocatalytic activity of the CNQDs/Bi3.64Mo0.36O6.55 photocatalyst.
关键词： Water purification,Bi3.64Mo0.36O6.55 nanospheres,Binary heterostructure,g-C3N4 quantum Dots,Photocatalytic activity
更新于2025-09-23 15:21:01
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Type-II/type-II band alignment to boost spatial charge separation: A case study of g-C3N4 quantum dot/a-TiO2/r-TiO2 for highly efficient photocatalytic hydrogen and oxygen evolution
摘要： Efficient spatial charge separation and transfer that are critical factors for solar energy conversion primarily depend on the energetic alignment of the band edges at interfaces in heterojunctions. Herein, we first report that constructing 0D/0D type-II(T-II)/T-II heterojunction is an effective strategy to ingeniously achieve long-range charge separation by taking a ternary heterojunction of TiO2 and graphitic carbon nitride (g-C3N4) as a proof-of-concept. Incorporating g-C3N4 quantum dots (QCN), as the third component, into the commercial P25 composed of anatase (a-TiO2) and rutile (r-TiO2) can be realized via simply mixing the commercially Degussa P25 and QCN solution followed by heat treatment. The strong coupling and matching band structures among a-TiO2, r-TiO2 and QCN result in the construction of novel T-II/T-II heterojunctions, which would promote the spatial separation and transfer of photogenerated electrons and holes. Moreover, QCN plays a key role in reinforcing light absorption. Specially, the unique 0D/0D architecture possesses the advantages of abundant active sites for photocatalytic reaction. As a result, the optimized QCN/a-TiO2/r-TiO2 heterojunctions exhibit enhanced photocatalytic H2 and O2 evolution, especially the hydrogen evolution rate (49.3 μmol h?1) is 11.7 times that of bare P25 under visible light irradiation, and sufficiently catalytic stability as evidenced by the recycling experiments. The remarkable enhanced photocatalytic activity can be attributed to the synergistic effects of the energy level alignment at interfaces, the dimensionality and component of the heterojunctions. This work provides a stepping stone towards the design of novel heterojunctions for photocatalytic water splitting.
关键词： type-II/type-II band alignment,0D/0D heterojunction,photocatalytic water splitting,g-C3N4 quantum dots,TiO2
更新于2025-09-19 17:13:59
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Mesoporous g-C3N4 ultrathin nanosheets coupled with QDs self-decorated SnIn4S8 homojunctions towards highly efficient photocatalytic functional transformation
摘要： In this research, we rationally designed and synthesized quantum dots self-decorated SnIn4S8/g-C3N4 (QDs-SISCN) nanocomposites by in situ anchoring quantum dot (QDs) self-decorated SnIn4S8 (SIS) nanosheets onto the surface of mesoporous graphite carbon nitride (CN) nanosheets in a mixed solvothermal environment. The photoreduction of 4-nitroaniline (4-NA) was used to assess their photocatalytic activity. In this framework, the construction of CN nanosheets-supported QDs-decorated SIS homojunctions can integrate the advantages of both homojunctions and heterojunctions. Benefiting from those favourable properties, the QDs-SISCN nanocomposites exhibit superior photocatalytic activity towards 4-NA reduction under visible-light irradiation (l > 400) as a result of the optimizied amount of CN nanosheets added. The recycling experiments also reveal high stability of the QDs-SISCN nanocomposites during photocatalytic reactions for 4-NA reduction. Moreover, the investigation of the photocatalytic mechanism from systematic characterizations, including measurements of the photocurrent response, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) indicate that the improved separation efficiency of charge carriers is a critical parameter for the enhanced photocatalytic activity for 4-NA reduction. We expect this research to provide a promising path to the design and synthesis of highly efficient hybrid photocatalysts for functional-group transformations.
关键词： Photocatalyst,SnIn4S8,g-C3N4,Quantum dots
更新于2025-09-12 10:27:22