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Enhancing photocatalytic activity of tantalum nitride by rational suppression of bulk, interface and surface charge recombination
摘要： Rational design of photocatalysts is essential to achieve efficient solar energy conversion. For narrow bandgap Ta3N5 photocatalyst, various charge recombination occurring in the bulk, interface and on the surface significantly impairs its activity for solar hydrogen (H2) generation. Herein, a synergistic engineering approach is designed to solve this critical recombination challenge. First, hollow spherical structure of Ta3N5 with Mg doping is prepared to not only reduce the charge migration distance and increase the surface area, but also increase the electron mobility for facilitated charge transfer. Second, an MgO nano-layer covers the surface of hollow Ta3N5 structure to passivate surface defects, thus promoting the interfacial charge transfer between Ta3N5 and co-catalysts. Finally, dual co-catalysts (Pt/CoOx) for redox reactions are loaded onto the hollow Ta3N5 structure to reduce the surface recombination and overcome the sluggish surface reaction. Remarkably, the combination of hollow structure, Mg2+ doping, MgO interfacial layer, and dual co-catalysts effectively improves the charge separation and transfer in Ta3N5 photocatalyst. This newly designed photocatalyst exhibits a considerably improved H2 generation performance of 56.3 μmol h-1 under simulated sunlight, compared to that of reference Pt/Ta3N5 hollow spheres.
关键词： doping,hollow structure,co-catalyst,surface passivation,tantalum nitride
更新于2025-09-19 17:15:36
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Synthesis of cocoon-like Ag3PO4 and its high-performance in photocatalytic degradation of ciprofloxacin
摘要： Cocoon-like Ag3PO4 (C-Ag3PO4) with hollow structure was synthesized via ion-exchange route using Ag2MoO4 and Na2HPO4 as precursors. Photocatalytic degradation experiments of the C-Ag3PO4 toward ciprofloxacin (CIP) were investigated under visible light irradiation. The C-Ag3PO4 showed superior photodegradation of CIP owing to its larger surface area and hollow structure. Besides, the C-Ag3PO4 exhibited improved photocatalytic performance and good stability after repeating cycles, which could be attributed to the formed metal silver under visible light irradiation. Moreover, radical trap experiment was carried out, which indicated that the photo-induced holes (h+) and superoxide radicals (?O2?) acted as the main reactive species in the photodegradation process.
关键词： Ciprofloxacin,Hollow structure,Semiconductors,Ag3PO4,Photocatalysis
更新于2025-09-19 17:15:36
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Synergistic enhancements in the performances of dye-sensitized solar cells by the scattering and plasmon resonance of Au-nanoparticle multi-shell hollow nanospheres
摘要： Novel multi-shell hollow SiO2@Au@TiO2 (HSAT) nanospheres are synthesized by multi-step method. Composite photoanodes and Dye-sensitized solar cells (DSSCs) with different amount of HSAT nanospheres are studied. The study indicates that the HSAT nanospheres have enhanced the scattering and absorption of incident light in the photoanode, reduced the interface transmission resistance, increased the electron lifetime, and thus significantly improved performance of DSSCs. The maximal Jsc and photoelectric conversion efficiency (PCE) obtained in the optimal DSSC doped with HSAT of 3.0% are 15.83 mA cm?2 and 7.21%, greatly enhanced by 21.0% and 20.4%, respectively, compared with those of the pure TiO2-based DSSC. These remarkable enhancements in DSSCs performance can be attributed to the synergistic and complementary effects of the localized surface plasmon resonance and strong light scattering of HSAT nanospheres, which has significantly improved the absorption and utilization on incident light and thus the PCE of the DSSCs. Such synergistic and complementary effects of the different functions are also likely expected to play roles in the performance improvements in other solar cells.
关键词： scattering enhancement,localized surface plasmon resonance,composite photoanodes,dye-sensitized solar cells,multi-shell hollow structure
更新于2025-09-19 17:13:59
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Hollow/porous-walled SnO2 via nanoscale Kirkendall diffusion with irregular particles
摘要： Hollow/porous structured SnO2 nanoparticles were synthesized by simple oxidation of dense metal chalcogenide precursors via nanoscale Kirkendall diffusion effect. First, tin chalcogenide (SnS, SnSe) nanoparticles were synthesized by mechanochemical method, which is considered a facile, scalable, and eco-friendly process. Hollow/porous-walled SnO2 nanoparticles were synthesized by simple oxidation of the prepared Sn chalcogenide precursors, for which the transformation mechanism was verified in detail. Nanoscale Kirkendall diffusion process was thoroughly investigated by morphological, crystallographic, and elemental analyses performed at various oxidation temperatures and times. To examine the morphological effect of hollow/porous-walled SnO2 nanoparticles on the electrochemical performance, the synthesized nanoparticles were applied as anode material in a lithium-ion battery. Anode material showed highly improved electrochemical properties compared to its dense counterpart, with 83% capacity retention from the second cycle at the 400th cycle and capacity of 302 mA h g-1 at a high current density of 30 A g-1.
关键词： chalcogenide,hollow structure,mechanochemical synthesis,porous particles,Kirkendall effect
更新于2025-09-16 10:30:52
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Preparation of hollow SiC ceramic fibre from polycarbosilane fibre by diffusion-controlled cross-linking method
摘要： Cross-linking is favourable for increasing ceramic yield and avoiding melting or deformation of SiC ceramic precursor polycarbosilane (PCS) during pyrolysis. In order to achieve hollow SiC fibre, PCS fibre with a limited cross-linking depth was prepared by chlorinating the Si–H group in the outer layer of PCS fibre followed by hydrolysis and condensation of the formed Si–Cl group. The chlorination was implemented through a gas–solid reaction between Cl2 and PCS fibre. Based on the results of energy-dispersive spectrometer and attenuated total reflectance–Fourier transform infrared spectroscopy, the diffusion-controlled chlorination reaction was confirmed. During hydrolysis, the catalysis of ammonia gas was necessary. According to the results of dissolution and degradation experiments, cross-linked PCS outer layer formed after chlorination, hydrolysis and condensation, and the outer layer had higher ceramic yield than the core part. After pyrolysis, SiC fibre with hollow morphology was formed. By adjusting the chlorination degree, the morphology of resulting hollow SiC fibre could be modified.
关键词： polycarbosilane,hollow structure,SiC fibre,cross-linked outer layer
更新于2025-09-16 10:30:52
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Titanium oxide hollow structure layer for dye sensitized solar cell by liquid phase deposition
摘要： In this study, polystyrene (PS) microspheres templates having different coating densities were prepared by drop casting PS microspheres with the diameter of 800 nm on indium tin oxide (ITO) glass substrate. TiO2 film was deposited on the PS microsphere template via liquid phase deposition (LPD) using a solution of ammonium hexafluoro-titanate [(NH4)2TiF6] and boric acid (H3BO3). A LPD-TiO2 hollow layer was prepared by removing PS microspheres via high-temperature sintering; this hollow layer acts as a barrier between the ITO and electrolyte interface in the working electrode structure of a dye-sensitized solar cell (DSSC). Because hollow layer has a large specific surface area, it increases dye adsorption and acts as a barrier layer to inhibit direct contact between ITO and electrolyte interface. Thus, the charge recombination rate between ITO and electrolyte interface is reduced and the electron transmission efficiency between the ITO and the working electrode is improved. Hollow layer (0.1 wt% PS, 50 nm) in the DSSC exhibited the optimum short-circuit current density (Jsc) of 12.75 mA/cm2, open-circuit voltage (Voc) of 0.71 V, fill factor of 62.19%, and photoelectric conversion efficiency (η) of 5.67%.
关键词： Hollow structure,Dye-sensitized solar cells,Titanium oxide,Barrier layer
更新于2025-09-16 10:30:52
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One-step synthesis of hollow BaZrO3 nanocrystals with oxygen vacancies for photocatalytic hydrogen evolution from pure water
摘要： It is very challenging to synthesize perovskite oxides with controlled morphology and defect states at the same time. In this work, the BaZrO3 hollow nanostructures with oxygen vacancies were facilely synthesized through one-step solvothermal method using ethylenediamine (EDA) as solvent. The as-synthesized BaZrO3 could split pure water into H2 without addition of sacrificial agent under UV light irradiation. The photocatalytic H2 production rate is about 15 times than that of the commercial BaZrO3 (BZO-C). It is believed that the presence of oxygen vacancies and the hollow morphology made contribution to the improvement of photocatalytic performance. This work provides a reference for microstructure and defect modification of photocatalysts at the same time to enhance the photocatalytic performance.
关键词： BaZrO3,Photocatalysis,Oxygen vacancy,Pure water,Hollow structure
更新于2025-09-09 09:28:46