电沉积制备WO_3电极及其对Cu可见光光电化学保护

采用阴极电沉积法制备了具有可见光光电响应的WO_3薄膜电极．考察了制备工艺条件和光反应体系组成对电极光电响应性能的影响．结果表明:沉积电位-0．45V(相对于饱和甘汞电极)、沉积时间1600s、烧结温度400℃时电极光电性能较好;在光电化学电池中,阳极室添加空穴捕获剂(如甲酸和升高溶液pH值,有利于光电流输出．在阳极室溶液组成为0．5mol/dm^3 Na_2SO_4+0．5mol/dm^3 HCOOH(pH9．6)时,WO_3薄膜电极在可见光光照下可对4mol/dm^3 NaCl溶液中金属Cu进行光电化学防腐蚀,为利用可见光实现对金属防腐蚀提供了一条新的途径．

Cu/WO_3-NiO上光促表面催化二氧化碳与水合成甲醇反应的规律

采用溶胶 凝胶法制备了n p复合半导体材料 0 75 %Cu/WO3 1 5 %NiO ,用X射线衍射、透射电镜、红外光谱、紫外 可见光漫反射和程序升温脱附等技术对材料结构、吸光性能和化学吸附性能进行了表征 ,研究了该材料对CO2 与H2 O合成CH3OH的光促表面催化反应 (PSSR)规律 .结果表明 :所制备的材料明显有利于促进目的反应 ,室温条件下就有CH3OH生成 ,选择性超过 90 % ,升高反应温度可提高CH3OH产量 ,且选择性仍高于 88% .根据实验结果 ,得出CO2 在材料表面的卧式吸附态为CH3OH的前驱物 。

Cu/ZnO-Pd/WO_3/ZrO_2催化甘油氢解制取1,2-丙二醇

为了提高铜基催化利在甘油氢解制1,2-丙二醇反应中的稳定性,制备Cu/ZnO和Pd/WO_3/ZRO_2混合催化剂采用H_2程序升温还原(H_2-TPR)、NH_3程序升温脱附(NH_3-TPD)和N_2吸附技术对催化剂的还原性能、酸性进行表征。在连续流动固定床反应器中考察Cu/ZnO-Pd/WO_3/ZrO_2混合催化剂对甘油氢解反应的催化活性和稳定性。结果表明:添加Pd/WO_3/ZrO_2可降低Cu/ZnO催化剂的还原温度;混合催化剂催化甘油氢解制1,2-丙二醇的稳定性与WO_3/ZrO_2的酸密度有顺变关系,WO_3/ZrO_3的酸密度越高,所构成的混合催化剂稳定性越好;均匀混合的Cu/ZnO-Pd/WO_3/ZrO_2催化剂对甘油氢解反应催化活性和稳定性高。

S-scheme Sb2WO6/g-C3N4 photocatalysts with enhanced visible-light-induced photocatalytic NO oxidation performance

Normal photocatalysts cannot effectively remove low-concentration NO because of the high recombination rate of the photogenerated carriers.To overcome this problem,S-scheme composites have been developed to fabricate photocatalysts.Herein,a novel S-scheme Sb2WO6/g-C3N4 nanocomposite was fabricated by an ultrasound-assisted method,which exhibited excellent performance for photocatalytic ppb-level NO removal.Compared with the pure constituents of the nanocomposite,the as-prepared 15%-Sb2WO6/g-C3N4 photocatalyst could remove more than 68%continuous-flowing NO(initial concentration:400 ppb)under visible-light irradiation in 30 min.The findings of the trapping experiments confirmed that•O2^–and h+were the important active species in the NO oxidation reaction.Meanwhile,the transient photocurrent response and PL spectroscopy analyses proved that the unique S-scheme structure of the samples could enhance the charge separation efficiency.In situ DRIFTS revealed that the photocatalytic reaction pathway of NO removal over the Sb2WO6/g-C3N4 nanocomposite occurred via an oxygen-induced route.The present work proposes a new concept for fabricating efficient photocatalysts for photocatalytic ppb-level NO oxidation and provides deeper insights into the mechanism of photocatalytic NO oxidation.

2D/2D step-schemeα-Fe2O3/Bi2WO6 photocatalyst with efficient charge transfer for enhanced photo-Fenton catalytic activity

Although the traditional Fenton reaction is considered an effective strategy for solving problems caused by environmental pollution,construction of an efficient photocatalytic system by coordinating the Fenton reaction is challenging.In this study,2D/2D step-schemeα-Fe2O3/Bi2WO6(FO/BWO)heterostructure photo-Fenton catalysts were successfully fabricated by a facile hydrothermal method.The as-prepared materials were characterized by XRD,FT-IR,TEM,XPS,UV-vis DRS,PL,I-t,EIS,and BET analyses.Under visible light irradiation,FO/BWO exhibited remarkably high and stable photo-Fenton catalytic activity for the degradation of methyl blue(MB)at low concentrations of H2O2.It was noted that FO/BWO(0.5)displayed a significantly enhanced photo-Fenton catalytic activity,which was 11.06 and 3.29 times those of FO nanosheets and BWO nanosheets,respectively.The notably improved photo-Fenton catalytic activity of FO/BWO was mainly due to the combination of H2O2 and FO under light illumination and the presence of the 2D/2D S-scheme heterostructure,with the large contact surface,abundant active sites,and efficient separation rate of photogenerated carriers playing contributory roles.Additionally,a possible catalytic mechanism for the FO/BWO composite was preliminarily proposed via active species trapping experiments.In summary,this study provided new insights into the synthesis of an effectively heterogeneous 2D/2D S-scheme photo-Fenton catalyst for degradation of organic pollutants in wastewater.

WO_3/ZrO_2-Cu/ZnO催化剂催化甘油氢解性能

采用共沉淀法制备Cu/ZnO催化剂,浸渍焙烧法制备WO3/ZrO2催化剂,将2种催化剂进行物理混合制得Cu/ZnO-WO3/ZrO2混合催化剂。通过H2程序升温还原(H2-TPR)、H2程序升温脱附(H2-TPD)等手段对催化剂的物化性质进行表征,在连续流动固定床反应器中考察Cu/ZnO-WO3/ZrO2催化剂对甘油氢解反应的催化性能。结果表明:添加WO3/ZrO2可改善催化剂的还原性能和氢吸附性能,催化剂的稳定性明显提高。在反应温度190℃、H2压力3 MPa、80%甘油水溶液、甘油质量空速0.6 h-1的反应条件下,3Cu/ZnO-WO3/ZrO2催化剂上能获得77.6%的甘油转化率和95.8%的1,2-丙二醇选择性,且反应200 h内,催化剂的催化性能基本无变化。

Ultrasonic-assisted synthesis of plasmonic Z-scheme Ag/AgCl/WO_3-nanoflakes photocatalyst in geothermal water with enhanced visible-light photocatalytic performance

In this study, the Ag/Ag Cl/WO3 plasmonic Z-scheme photocatalysts with different contents of Ag/Ag Cl nanoparticles（NPs） were prepared through a facile ultrasonic precipitation method in geothermal water,wherein the geothermal water served as the chlorine source. Then the photocatalytic activity was investigated by degradation of 4-Aminobenzoic acid（4-ABA） under visible-light irradiation. It was found that the as-prepared 50 wt% Ag/Ag Cl/WO3 photocatalyst showed the highest photocatalytic efficiency with 25.12 and 3.53 times higher than those of pure WO3 and Ag/Ag Cl, respectively. The active species trapping experiments indicated that h＋and ·O2-were key factors in 4-ABA photodegradation process. The possible plasmonic Z-scheme photocatalytic mechanism of photocatalytic reaction for 4-ABA degradation was proposed based on systematical characterizations. We hope this paper could give new ideas for further exploiting geothermal energy to design and fabricate highly efficient visible-light-driven photocatalysts for environmental remediation.

The Synergistic Antibacterial Performance of a Cu/WO₃-Added PTFE Particulate Superhydrophobic Composite Material

The synergistic antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) of a Cu/WO3-added PTFE (polytetrafluoroethylene) particulate composite was reported in the previous paper. The origin of the synergistic antibacterial performance investigated by evaluating the photocatalytic decomposition of the Cu/WO3-added PTFE particulate composite material is reported in the present paper. Addition of Cu/WO3, visible-light-sensitive photocatalyst, to the PTFE particle dispersed superhydrophobic composite does not deteriorate the superhydrophobic property of the composite. Furthermore the existence of the polytetrafluoroethylene (PTFE) particles dispersed in the composite enhances the antibacterial property caused by the Cu/WO3. The authors call this “The synergistic effect”. In this study, a novel synergistic property of the Cu/WO3-added PTFE particulate composite was investigated by evaluating the degradation of gaseous acetaldehyde on the composite surface using visible light (10,000 lx) and UV-A (1 mW·cm-1) illumination. The 12 wt% Cu/WO3-8 wt% binder-80 wt% PTFE composite shows the synergistic visible-light-sensitive photocatalytic property. But 12 wt% Cu/WO3-44 wt% PTFE-44 wt% binder composite no longer shows the synergistic property of visible-light-sensitive photocatalytic property. The synergetic performance of visible-light-sensitive photocatalytic property appears only when PTFE concentration is larger than the critical point over which superhydrophobic property appears in accordance with the particulate composite model derived by the one of the authors. The hydrophobic surface leads to the low surface free energy derived by the revised Fowkes’s theory, which makes it difficult for bacteria to stick to the hydrophobic surface of the composite. Even if bacteria stick to the surface, they are decomposed by the visible-light-sensitive photocatalyst. This is the reason why the synergistic antibacterial performance against bacteria appears.

Synergistic Antibacterial Performance of a Cu/WO₃-Added PTFE Particulate Superhydrophobic Composite under Visible-Light Exposure

Addition of TiO2 to a polytetrafluoroethylene (PTFE) particle-dispersed composite contributes to the self-cleaning properties of the water-repellent composite. However, its application is limited to outdoor usage or under ultraviolet (UV) irradiation. In this study, a novel visible-light-sensitive photocatalytic and superhydrophobic material was developed by adding Cu/WO3 to a PTFE particulate composite material to overcome this deficit. A remarkable property of this novel composite material is the synergistic antibacterial performance against Escherichia coli (E. coli), Staphylo-coccus aureus, and methicillin-resistant Staphylococcus aureus compared with the addition of Cu/WO3 without PTFE particles material. During 24-h exposure in visible light at 2000 lx, the number of viable cells of the three strains on the surface of the 8wt% Cu/WO3-added PTFE particulate composite decreased from 2 – 4 × 105 colony-formation units (CFUs) to less than 10, the limit of detection. This bactericidal rate is four times higher than that of 8wt% Cu/WO3 without PTFE particles material, which is attributed to the air trapped in the rough surface of the novel material providing additional oxygen to the photocatalytic reaction. Even for exposure to visible light at 100 lx, the decrease in CFUs of E. coli on the 12wt% Cu/WO3-added PTFE particulate composite reached nearly 2.0 logs. The characterization of the Cu/WO3-added PTFE particulate composite indicated that the composite material containing 80wt% PTFE maintained a superhydrophobic or water-repellent property with a water contact angle >150。, although the Cu/WO3 in the composite material remained hydrophilic under visible light. The Cu/WO3-added PTFE particulate composite displayed photo-catalytic reactions to decompose oleic acid adsorbed on its surface and gaseous acetaldehyde under UV-A and visible-light illumination. All results demonstrate that the Cu/WO3-added PTFE particulate composite material may be used in sterilization, as a water repellent, for self-cleaning, and in the oxidative decomposition of volatile organic compounds (VOC) both indoors and outdoors.

Ag/AgCl@WO3/MIL-101可见光催化剂的合成及其光催化性能的研究

采用微波辅助合成方法将WO3固载到金属有机骨架MIL-101(Cr)上,借助于沉积沉淀–光还原方法将Ag/AgCl和WO3/MIL-101复合在一起,制备出Ag/AgCl@WO3/MIL-101可见光催化剂。利用FT-IR、XRD、UV-Vis-DRS和XPS测试技术对该催化剂进行了表征。结果表明,Ag/AgCl和WO3的引入没有改变MIL-101的结构,催化剂在可见光区有强烈的光吸收。当WO3的负载量为0.3(w)%,Ag的负载量为3.4(w)%时,Ag/AgCl@WO3/MIL-101对70 mL 20 mg/L的罗丹明B溶液的降解率达到100%,并且该催化剂具有较好的稳定性。

Designing all-solid-state Z-Scheme 2D g-C_3N_4/Bi_2WO_6 for improved photocatalysis and photocatalytic mechanism insight

Bi_2WO_6 was modified by two-dimensional g-C_3N_4(2D g-C_3N_4)via a hydrothermal method.The structure,morphology,optical and electronic properties were investigated by multiple techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy spectra(XPS),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Ultravioletvisible diffuse reflection spectroscopy(DRS),photocurrent and electrochemical impedance spectroscopy(EIS),electron spin resonance(ESR),respectively.Rhodamine B(Rh B)was used as the target organic pollutant to research the photocatalytic performance of as-prepared composites.The Bi_2WO_6/2D g-C_3N_4exhibited a remarkable improvement compared with the pure Bi_2WO_6.The enhanced photocatalytic activity was because the photogenerated electrons and holes can quickly separate by Z-Scheme passageway in composites.The photocatalytic mechanism was also researched in detail through ESR analysis.

Anticorrosion of WO₃-Modified TiO₂Thin Film Prepared by Peroxo Sol-Gel Method

The aim of this study was to develop a method to prepare WO3-TiO2 film which has high anticorrosion property when it was coated on type 304 stainless steel. A series of WO3-modified TiO2 sols were synthesized by peroxo-sol gel method using TiCl4 and Na2WO4 as the starting materials. TiCl4 was converted to Ti(OH)4 gel. H2O2 and Na2WO4 were added in Ti(OH)4 solution and heated at 95°C. The WO3-TiO2 sol was transparent, in neutral (pH^7) solution, stable suspension without surfactant, nano-crystallite and no annealing is needed after coating, and very stable for 2 years in stock. WO3-TiO2 sol was formed with anatase crystalline structure. These sols were characterized by XRD, TEM, and XPS. The sol was used to coat on stainless steel 304 by dip-coating. The WO3-TiO2 was anatase in structure as characterized by X-ray diffraction. There were no WO3 XRD peaks in the WO3-TiO2 sols, indicating that WO3 particles were very small, possibly incorporating into TiO2 structure, providing the amount of WO3 was very small. The TiO2 particles were rhombus shape. WO3-TiO2 had smaller size area than pure TiO2. The SEM results showed that the film coated on the glass substrate was very uniform. All films were nonporous and dense films. Its hardness reached 2 H after drying at 100°C, and reached 5 H after annealing at 400°C. The WO3-TiO2 film coated on 304 stainless steel had better anticorrosion capability than the unmodified TiO2 film under UV light illumination. The optimum weight ratio of TiO2: WO3 was 100:4.

溶胶-喷雾干燥W-Cu前驱体粉末煅烧过程中的相变

采用溶胶-喷雾干燥法制备不同铜含量的W-Cu前驱体粉末,前驱体粉末分别在400、600和800℃各煅烧90min,运用XRD和SEM等手段对煅烧前后复合粉末的相组成和显微形貌进行分析,研究前驱体粉末在煅烧过程中的相变行为。结果表明:前驱体粉末在煅烧过程中发生一系列的分解和化合反应,随着煅烧温度的升高,粉末的相组成、颗粒形貌和尺寸发生明显变化,对W-30%Cu(质量分数)合金,在400℃煅烧后,复合粉末由WO3、CuO和CuWO4组成,粉末颗粒大多呈立方结构,大小为200～400nm;在600℃煅烧后,复合粉末由CuO和CuWO4组成,粉末颗粒大多呈短棒状结构,大小为400～500nm;在800℃煅烧后,复合粉末由CuO、CuWO4和Cu3WO6组成,粉末颗粒大小为3～4μm;前驱体粉末中铜含量对煅烧后复合粉末的相组成也存在较大影响,铜含量越多,越容易生成复合氧化物。

Investigation of solar-induced photoelectrochemical water splitting and photocatalytic dye removal activities of camphor sulfonic acid doped polyaniline-WO3-MWCNT ternary nanocomposite

The camphor sulfonic acid doped polyaniline-WO3-multiwall carbon nanotube(CSA PANI-WO3-CNT)ternary nanocomposite was synthesized during in-situ oxidative polymerization and characterized by Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,X-ray diffraction(XRD),Field emission scanning electron microscopy(FESEM),X-ray photoelectron spectroscopy(XPS),Transmission electron microscopy(TEM),and Energy-dispersive X-ray spectroscopy(EDS).The application of CSA PANIWO3-CNT ternary nanocomposite was investigated as the photocatalyst in the degradation of methylene blue dye(MB)and as the noble metal-free photoanode in photoelectrochemical water splitting under solar light irradiation.The degradation percentage of MB dye after 60 min illumination by CSA PANI-WO3-CNT ternary nanocomposite reached 91.40%which was higher than that of pure WO3(43.45%),pure CSA PANI(48.4%)and CSA PANI-WO3 binary nanocomposite(85.15%).The photocurrent density of indium tin oxide(ITO)/CSA PANI-WO3-CNT photoanode obtained 0.81 m A/cm2 at 1.23 V vs.reversible hydrogen electrode under illumination which was 1.27,2.13,and 4.26 times higher than that of the ITO/CSA PANI-WO3(0.64 m A/cm2),ITO/pure CSA PANI(0.38 m A/cm2),and ITO/pure WO3(0.19 m A/cm2).Also,the applied bias photon-to-current efficiency(ABPE)of ITO/CSA PANI-WO3-CNT was obtained 0.11%which showed two-fold,four-fold,and five-fold enhancements compared to the ITO/CSA PANI-WO3,ITO/CSA PANI,and ITO/WO3,respectively.The electrochemical impedance spectroscopy,as well as the Mott-Schottky results,confirmed the better photoelectrocatalytic activity of ITO/CSA PANI-WO3-CNT in comparison with ITO/WO3,ITO/CSA PANI,and ITO/CSA PANI-WO3.The observed improvement in the photocatalytic and photoelectrocatalytic performances of WO3 in the presence of CSA PANI is due to the formation of type-II heterojunction between WO3 and CSA PANI which allows the separation of charge carriers easier and faster.On the other hand,MWCNT addition to the CSA PANI-WO3 nanocomposite provided the conducting substrate for efficient interfacial charge separation as well as transferring.

三氧化钨纳米粒子的改性研究进展

三氧化钨(WO3)能被用作可见光响应光催化剂,但由于导带位置较低、在本体中光生电荷载流子复合几率较高等因素,导致其量子产率较低,从而制约了其实际应用。所以,需要对WO3进行改性以提高其光催化性能。结合近年来国内外相关文献,综述了WO3掺杂改性的研究现状,并对WO3基光催化材料的发展趋势进行了展望。