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A facile in situ growth of CdS quantum dots on covalent triazine-based frameworks for photocatalytic H2 production
摘要： CdS quantum dots (QDs) are excellent visible-light-driven photocatalysts due to their unique small size (<10 nm), suitable band energy structure, and short charge transportation length. Unfortunately, the easy aggregation of CdS QDs to form larger particles results in a higher recombination rate for photoinduced electron-hole pairs, which deteriorates the photocatalytic activity. Here, we report in situ growth of CdS QDs with high dispersion and stability on covalent triazine-based frameworks (CTFs) via a facile photoreduction method. The photocatalytic H2 evolution activity of CdS QD-loaded CTFs is effectively enhanced to approximately 55 and 4 times than that of pristine CTFs and bulk CdS, respectively. This enhanced photocatalytic performance is mainly ascribed to the higher separation rate of photogenerated carriers resulting from synergistic QD-on-sheet interactions between CdS QDs and CTFs. This work develops an efficient one-pot strategy to prepare metal-sulfide QDs with high dispersion and underlines the potential of utilizing CTFs as a suitable platform to develop efficient photocatalytic systems.
关键词： In situ growth,CdS QDs,Photocatalysis,Visible light,H2 evolution,Covalent triazine-based frameworks
更新于2025-09-23 15:19:57
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Thermal Shock Synthesis of Metal Nanoclusters within On-the-fly Graphene Particles
摘要： Metal nanoclusters (1-10 nm) have drawn great attention due to their potential applications including energy storage, catalysis, nanomedicine and electronic devices. However, manufacturing ultra-small metal nanoparticles at high concentrations in an unaggregated state is not a solved problem. Here we report an aerosol-based thermal shock technique for in situ synthesis of well-dispersed metal nanoclusters in on-the-fly graphene aerosols. A rapid thermal shock to the graphene aerosol has been used to nucleate and grow the metal nanoclusters with subsequent quenching to freeze the newly formed nanoclusters in the graphene aerosol matrix. A characteristic time analysis comparison with experiment shows that the nanocluster formation is governed by nucleation and subsequent surface growth, and that the graphene retards coagulation, enabling unaggregrated metal nanoclusters. The method is generic, and we show the formation of sub-10 nm Ni, Co and Sn nanoclusters. This continuous aerosol-based thermal shock technique offers considerable potential for the scalable synthesis of well-dispersed and uniform metal nanoclusters stabilized within a host matrix. As an example of potential application, we demonstrate very favorable catalytic properties.
关键词： thermodynamics,in situ growth,growth mechanism,thermal shock synthesis,kinetics,metal nanoclusters
更新于2025-09-19 17:15:36
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Hierarchical WO3/ZnWO4 1D fibrous heterostructures with tunable in-situ growth of WO3 nanoparticles on surface for efficient low concentration HCHO detection
摘要： Hierarchical WO3/ZnWO4 1D fibrous heterostructures with tunable in-situ growth of WO3 nanoparticles on surface have been fabricated by the original one-step electrospinning technology combined with subsequent calcination process. Phase composition and morphology can be transformed from bead-like WO3 fibers to hierarchical WO3/ZnWO4 1D composites with the introduction of ZIF-8 into the precursor solution, which was mainly attributed to the combination of nucleation competition and crystal planes matching mechanisms during heat treatment. Compared with pure WO3 and WO3/ZnWO4-10%, WO3/ZnWO4-5% displayed the highest specific surface area value evaluated to be 268.57, indicating the prominent enhanced absorption behavior for targeted organic species. It is found that WO3/ZnWO4-5% composites have a response about 44.5 for 5 ppm HCHO, which was almost 8 times higher than that of sensor based on pure WO3 nanofibers at the optimal operating temperature. Meanwhile, the fast response/recovery time (12/14 s) and excellent stability characteristics (recycling, long-term, and humidity stability) towards HCHO can be also observed for WO3/ZnWO4-5% samples. The enhanced gas-sensing mechanism based on WO3/ZnWO4 composites can be ascribed to the synergistic effect of effective heterojunctions, large specific surface area, multiple reaction sites, and unique surface/interface electron transmission. The design and construction of hierarchical WO3/ZnWO4 1D materials attest to the significant potential of their use as novel gas sensors for detecting low concentration HCHO.
关键词： electrospinning,gas sensors,in-situ growth,HCHO,WO3/ZnWO4 heterostructures
更新于2025-09-19 17:15:36
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Polydopamine-Assisted Fabrication of Stable Silver Nanoparticles on Optical Fiber for Enhanced Plasmonic Sensing
摘要： We present a facile and effective method for fabrication of the localized surface plasmon resonance (LSPR) optical fiber sensor assisted by two polydopamine (PDA) layers with enhanced plasmonic sensing performance. The first PDA layer was self-polymerized onto the bare optical fiber to provide the catechol groups for the reduction from Ag+ to Ago through chelating and redox activity. As the reduction of Ag+ proceeds, Ag nanoparticles (NPs) were grown in-situ on the PDA layer with uniform distribution. The second PDA layer was applied to prevent Ag NPs from oxidating and achieve an improvement of LSPR signal. The PDA/Ag/PDA-based optical fiber sensor has an enhanced LSPR sensitivity of 961 nm/RIU and excellent oxidation resistance. The stable PDA/Ag/PDA-based LSPR sensor with high optical performance is very promising for future application in optical sensing field.
关键词： silver nanoparticles,in-situ growth,optical fiber,LSPR,polydopamine
更新于2025-09-11 14:15:04