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Formation mechanism of porous rose-like WO3 and its photoresponse and stability study
摘要： WO3 materials are widely used in photocatalysis and electrocatalysis. In this work, sodium dodecyl benzene sulfonate (SDBS) was used to control the growth of H2WO4 during chemical bath deposition fabrication process. The as-prepared H2WO4 material showed a rose-like morphology and after annealing the obtained WO3 sample was porous with oxygen defects. XRD, SEM, TEM, XPS and some other method were used to characterize the samples. A possible growth mechanism was given depending on the characterization results. The addition of SDBS resulted in a simultaneous growth of plenty H2WO4 nucleus, which caused a uniform distribution. Compared with normal WO3, the as-fabricated porous rose-like WO3 showed a higher stability to photocorrosion and a narrower band gap.
关键词： porous,photocatalysis,electrocatalysis,oxygen defects,WO3,SDBS
更新于2025-09-23 15:19:57
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Zn-Free MOFs like MIL-53(Al) and MIL-125(Ti) for the preparation of defect-rich, ultrafine ZnO nanosheets with high photocatalytic performance
摘要： Metal organic frameworks (MOFs) are exploited in many applications of materials science and very recently were investigated as precursors or reagents for material synthesis. In a new way different from previous approaches, here we introduce for the first time the synthesis of metal oxide MxOy in the presence of M-free MOF acting partially as a sacrificial template and as a provider of doping metal atom. We demonstrate this approach in the case of ZnO prepared by a simple hydrothermal method in the presence of a Zn-free MOF like MIL-53(Al) or MIL-125(Ti). The resulting ZnO show low content of Al or Ti < 2% and properties are significantly different depending on whether MIL-53(Al) or MIL-125(Ti) are used or if no MOF is present. The nature and presence of MOF has different major effects on the morphology, the specific surface area of as prepared ZnO and also on the oxygen defects in its crystal structure. Corroborating the XPS, UV-Vis DRS, PL, EPR and DFT studies evidence the role of such O-defects on band gap narrowing for samples calcined at 400°C. These exhibit high efficiency in photodegradation of methyl orange (MO) compared to ZnO prepared in MOF-free conditions or previous literatures. The kinetics of MO degradation is different depending on the morphology, the specific surface and oxygen defects. The present data open the door to a new approach of the synthesis of metal oxides and a control of their properties
关键词： Oxygen defects,Zinc oxide,MOFs,Template,Photocatalysis
更新于2025-09-10 09:29:36
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Oxygen vacancy‐rich anatase TiO2 hollow spheres via liquid nitrogen quenching process for enhanced photocatalytic hydrogen evolution
摘要： Development of novel methods to obtain highly active catalysts for photocatalytic hydrogen evolution is desired. This work reports a facile preannealing-quenching strategy to synthesize oxygen vacancy-rich anatase TiO2 hollow spheres. TiO2 hollow spheres are first synthesized via a versatile kinetics-controlled coating method and then subjected to high temperature preannealing followed by rapid quenching in liquid-nitrogen (-196 oC). The as-quenched samples appear light grey suggesting the presence of abundant surface oxygen vacancies, which are subsequently confirmed by the comprehensive analyses of XRD, XPS and EPR spectra. The oxygen vacancies induced by quenching process are proved to have promoted the light adsorption and inhibited the recombination of photo-induced charges for TiO2 hollow spheres, which obviously improve the photocatalytic performance of those samples. The results showed that the TiO2 hollow spheres quenched at 500 oC exhibited a robust stability and the most excellent photocatalytic performance for hydrogen evolution (413.5 μmol·h-1) over other quenched samples and it displayed 1.51 times higher performance than that of samples normally cooled at 500 oC (273.7 μmol · h-1). Herein, this liquid-nitrogen quenching strategy presented here provides an effective route for the synthesis of high-performance TiO2 for water splitting and have a promising prospect in the other application.
关键词： quenching,hollow spheres,photocatalytic hydrogen evolution,oxygen defects,titanium dioxide
更新于2025-09-04 15:30:14