| In this paper,a series of WOx micro-nano structures with different morphologies,including flower-like,urchin-like,nanowire-like,hollow microsphere-like,were synthesized by hydrothermal/solvothermal method.Noble metal surface modification and heterojunction construction of WOx micro-nano structures were carried out by light deposition,calcination method,room temperature stirring deposition method to optimize its performances in the fields of adsorption,photocatalysis and gas sensitivity,and the mechanisms of performances enhancement were explored.The main research contents of this paper are as follows:1.WOx with different morphologies and crystal phases were prepared by adjusting the experimental parameters.Their adsorption and photocatalytic performances were compared,and the mechanisms were analyzed.The results of adsorption experiments showed that the adsorption performances of WO2.72 to methylene blue（MB）were better than that of WO3.The photocatalytic experiments results showed that WO2.72 had a higher removal rate to MB than WO3,which was mainly because their adsorption performances were better than WO3,but WO3had better photodegradation ability than WO2.72.Among them,WO2.72 nanowires（sample 9）possess the best adsorption performances.Therefore,the effects of initial dye concentration,contact time,pH value,dye type and solution temperature on the adsorption performances of WO2.72 nanowires（sample 9,10,11）prepared with different experimental parameters were further investigated.The results showed that the adsorption performance of sample 10 was the best.Its adsorption efficiency for MB can acheive 100（4）within 6 min,and its maximum adsorption capacity can reach 547.32 mg/g.A variety of adsorption kinetic models and isotherm models were used,and the fitting results showed that the adsorption of MB by sample was in accordance with the quasi-second-order kinetics model and the Langmuir isotherm model.The adsorption mechanism is mainly electrostatic adsorption and hydrogen bonding.2.Au nanoparticles with different mass ratios were modified on WO2.72 microspheres by self-reduction combined with photodeposition,and their gas-sensitive performances were investigated.The results of gas-sensitive experiments show that Au/WO2.72 composite has higher response and faster response/recovery time to trimethylamine gas than WO2.72.At 260?C,the response of 3 wt%Au/WO2.72 to 100 ppm trimethylamine can reach 87.3,which is about6.1 times that of pure WO2.72.The Au/WO2.72 sensor showed good stability within 30 days.The analysis results of the gas-sensing mechanisms indicate that the enhanced gas sensitivity properties were attributed to the synergistic effects of the large specific surface area,the sensitization of Au,and the specific electron transfer between Au and WO2.72.3.PdO and Au nanoparticles were deposited on WO2.72 microspheres by calcination and photodeposition methods,respectively,and the gas-sensing performances of Au/PdO/WO2.72composite were investigated.Firstly,PdO/WO2.72 composite with different mass ratios were prepared.The gas-sensing test results showed that the 2 wt（4）PdO/WO2.72 had the best gas-sensitivity to trimethylamine.Then,Au nanoparticles were further loaded on 2 wt（4）PdO/WO2.72,and Au/PdO/WO2.72 three-phase composite structures with different Au content were prepared.The gas-sensing results showed that the response of Au（2wt）（4）</sub>/PdO（2wt）（4）</sub>/WO2.72to 40 ppm trimethylamine can reach 802.5,which is 110.5 times that of WO2.72.Au/PdO/WO2.72sensors not only have fast response/recovery time,but also have good long-term effectiveness and humidity stability.The mechanisms analysis revealed that the improved gas sensing properties of Au/PdO/WO2.72 sensors were ascribed to the synergy of surface area,p-n heterojunction,and catalytic sensitization of PdO and Au nanoparticles.4.By adjusting the amount of Ag3PO4 from 20 wt%to 50 wt%,a series of Ag3PO4/WO3composite structures with different morphologies were obtained by room temperature stirring deposition method,and their photocatalytic degradation and bactericidal properties were explored.The experimental results showed that the 40 wt（4）Ag3PO4/WO3（40APW）exhibited the best photocatalytic degradation performance to RhB.Its degradation efficiency to RhB（50mL,10 mg/L）can reach 100%within 10 min.Moreover,the photocatalytic bactericidal efficiency of 40APW to E.coli can reach 97%.The photocatalytic mechanism analysis showed a heterojunction is formed between Ag3PO4 and WO3,which promotes the separation of photogenerated electrons and holes,thus improving the photocatalytic performance. |
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