The objective in this study is to investigate the adsorption-degradation of the methylene blue(MB)dye using a fabricated heterojunction Ag@TiO_(2)nanocomposite.The batch factors used in photo catalytic reactions were ...The objective in this study is to investigate the adsorption-degradation of the methylene blue(MB)dye using a fabricated heterojunction Ag@TiO_(2)nanocomposite.The batch factors used in photo catalytic reactions were pH,UV-irradiation time,temperature,catalytic dosage,and concentration of MB.The results showed that 0.2×10^(3) g·ml^(-1))of the catalytic dose caused the Ag@TiO_(2)adsorption to degrade by 96.67%with darks and UV exposure.Using the Langmuir-Hinshelwood model to determine the kinetic,the Ag@TiO_(2)displays a greater kinetic rate than TiO_(2)and silver nanoparticle(AgNPs).The photocatalytic degradation of MB,which is an endothermic reaction involving all catalysts,is shown by the thermodynamic parameter to have the positive value of enthalpy(ΔH°).The enthalpies observed were Ag@TiO_(2)(126.80 kJ·mol^(-1))<AgNPs(354.47 kJ·mol^(-1))<TiO_(2)(430.04 kJ·mol^(-1)).Ascorbic acid(·OH scavenger),2-propanol(·O_(2)scavenger),and ammonium oxalate(AO)(hole h+scavenger)were employed to conduct the scavenger effects.The Ag@TiO_(2)demonstrated a reduction in MB degradation when combined with 2-propanol,and this clearly demonstrated that,in contrast to hydroxyl radicals(·OH)and holeh scavengers,superoxide radical anion(O_(2)scavenger)plays a significant role in MB degradation.Utilizing density functional theory(DFT)to elucidate the mechanism and B3LYP/6-311+G(d,p)level optimization,the degradation-adsorption process was explained.When the N-N,C-N or C-C bonds were severed,the Fukui faction was demonstrated for nucleophilic,electrophilic,and radical attack.展开更多
The synthesis and characterization of a new nanocomposite material that was prepared from recycled expanded polystyrene (EPS) and titanium dioxide (TiO2) is reported here. The EPS was obtained from chemical reagent bo...The synthesis and characterization of a new nanocomposite material that was prepared from recycled expanded polystyrene (EPS) and titanium dioxide (TiO2) is reported here. The EPS was obtained from chemical reagent box insulation. To obtain the nanocomposite, these materials were dispersed in a solvent, mixed with TiCl4 and heated. The resulting new material was characterized with SEM, TEM, TGA, BET, Raman and IR techniques. The Raman and IR spectra provided complementary information regarding the structure of the nanocomposite. The Raman spectra were used to identify the crystalline structure of TiO2 in the nanocomposite. In contrast, the IR spectra were used to identify the organic portion of the nanocomposite. The TEM images indicated that the nanocomposites had an average particle size of 6 - 12 nm. In addition, the adsorption and photocatalytic properties of the new material were evaluated. The EPS/TiO2 nanocomposite was efficient at degrading methylene blue (MB) dye solutions under UV irradiation. Furthermore, according to thermal analysis, this material had greater polymer stability due to the incorporation of TiO2.展开更多
CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity...CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity and photo-catalysis. The synthesized nanocomposites were characterized by BET, UV-VIS, XRD, FE-SEM (EDAX) techniques. X-Ray diffraction (XRD) reveals crystallite size to be 23.22 nm which was calculated using Williamson-Hall (W-H) plot method. The energy of the band gap for CdS/NiS could be thus estimated to be 3.26 eV. The photocatalytic activity of the sample was evaluated by the degradation of textile dye methylene Blue (MB) in aqueous solutions under UV radiation. Hydrogen energy is regarded as a promising alternative in terms of energy conversion and storage. Hydrogen Evolution Reaction (HER) was carried out in both visible light and UV light by using Hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) in the presence of CdS/NiS nanocomposite. The synthesized photocatalyst shows applicable performance for kinetics of Hydrogen Evolution Reaction (HER) in Visible light and UV light. The decomposition of hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) proceeded rapidly to generate free hydrogen rich gas through OH radical contact with CdS/NiS nanocomposite at room temperature. The rate of HER is limited by either proton adsorption onto an active site or evolution of formed hydrogen from the surface. A high Tafel slope is indicative of proton adsorption as the rate limiting step, while a lower Tafel slope (20 - 45 mV) indicates that the evolution of molecules hydrogen from the catalyst is rate limiting. In the present case the Tafel slopes for visible light 23.5 mV and 42.5 mV for UV light. Blank experiments show poor activity for HER <em>i.e.</em> 10.1 - 13.5 mV.展开更多
Recently,MXenes have attracted considerable attention owing to their unique physical and chemical properties.Construction of MXenes to three-dimensional(3D)porous aerogel structures can play a critical role in realizi...Recently,MXenes have attracted considerable attention owing to their unique physical and chemical properties.Construction of MXenes to three-dimensional(3D)porous aerogel structures can play a critical role in realizing the profound implications of MXenes,especially for environmental remediation.Nevertheless,developing mechanically robust MXene-based aerogels with reversible compressibility under harsh conditions,such as liquid environments,remains challenging due to the insufficient interfacial strength between MXene nanosheets.Herein,3D porous MXene-based nanocomposite aerogels are developed by dual physical and chemical crosslinking strategy with poly(vinyl alcohol)and formaldehyde in this study.The developed MXenebased nanocomposite aerogels with designed interfacial engineering exhibit outstanding structural stability and extremely high reversible compressibility up to 98%strain as well as unprecedented mechanical durability(2000 cycles at 50%strain)in water environment.Moreover,the aerogels show adaptable compressibility when exposed to different solvents,which is explained with the Hansen solubility parameter.Thanks to their high compressibility in water,the robust MXene-based aerogels exhibit excellent methylene blue adsorption performance(adsorption capacity of 117.87 mg·g^(−1))and superior recycling efficiency(89.48%at the 3rd cycle).The porous MXene-based nanocomposite aerogels are also demonstrated with outstanding thermal insulation capability.Therefore,by synergistically taking their porous structure and super elasticity in liquid environment,the MXene-based aerogels show great promise in diverse applications including adsorption and separation,wastewater purification desalination,and thermal management.展开更多
利用磁场作用将金-普鲁士蓝磁性纳米复合物（Au-PB）固定于磁性碳糊电极（MCPE）表面,进而通过金-氨键组装辣根过氧化物酶（HRP）,根据Au-PB与HRP共同催化还原H2O2作用,制备了一种用于过氧化氢检测的修饰电极（MCPE/Au-PB/HRP）.利用循...利用磁场作用将金-普鲁士蓝磁性纳米复合物（Au-PB）固定于磁性碳糊电极（MCPE）表面,进而通过金-氨键组装辣根过氧化物酶（HRP）,根据Au-PB与HRP共同催化还原H2O2作用,制备了一种用于过氧化氢检测的修饰电极（MCPE/Au-PB/HRP）.利用循环伏安法（CV）和电化学交流阻抗谱（EIS）对电极的修饰过程进行了表征,初步研究了MCPE/Au-PB/HRP对不同浓度H2O2的响应性能,其检测灵敏度为42.28 m V/decade,线性响应范围为3.53×10-6～3.53×10-3M,相关系数为0.998 6,检测下限为1.96×10-6M.所制备的修饰电极响应迅速、灵敏度高、检测范围较宽,适用于微量H2O2的快速检测,为有机磷农药传感器的制备奠定了基础.展开更多
基金University of Burdwan was for instrumental and financial support from DST-FIST(SR/FST/ESI-141/2015,dt:30.09.2019)Govt.of India and WBDST-BOOST(39/WBBDC/1p-2/2013,dt:25.03.2015),Govt.of West Bengal.
文摘The objective in this study is to investigate the adsorption-degradation of the methylene blue(MB)dye using a fabricated heterojunction Ag@TiO_(2)nanocomposite.The batch factors used in photo catalytic reactions were pH,UV-irradiation time,temperature,catalytic dosage,and concentration of MB.The results showed that 0.2×10^(3) g·ml^(-1))of the catalytic dose caused the Ag@TiO_(2)adsorption to degrade by 96.67%with darks and UV exposure.Using the Langmuir-Hinshelwood model to determine the kinetic,the Ag@TiO_(2)displays a greater kinetic rate than TiO_(2)and silver nanoparticle(AgNPs).The photocatalytic degradation of MB,which is an endothermic reaction involving all catalysts,is shown by the thermodynamic parameter to have the positive value of enthalpy(ΔH°).The enthalpies observed were Ag@TiO_(2)(126.80 kJ·mol^(-1))<AgNPs(354.47 kJ·mol^(-1))<TiO_(2)(430.04 kJ·mol^(-1)).Ascorbic acid(·OH scavenger),2-propanol(·O_(2)scavenger),and ammonium oxalate(AO)(hole h+scavenger)were employed to conduct the scavenger effects.The Ag@TiO_(2)demonstrated a reduction in MB degradation when combined with 2-propanol,and this clearly demonstrated that,in contrast to hydroxyl radicals(·OH)and holeh scavengers,superoxide radical anion(O_(2)scavenger)plays a significant role in MB degradation.Utilizing density functional theory(DFT)to elucidate the mechanism and B3LYP/6-311+G(d,p)level optimization,the degradation-adsorption process was explained.When the N-N,C-N or C-C bonds were severed,the Fukui faction was demonstrated for nucleophilic,electrophilic,and radical attack.
文摘The synthesis and characterization of a new nanocomposite material that was prepared from recycled expanded polystyrene (EPS) and titanium dioxide (TiO2) is reported here. The EPS was obtained from chemical reagent box insulation. To obtain the nanocomposite, these materials were dispersed in a solvent, mixed with TiCl4 and heated. The resulting new material was characterized with SEM, TEM, TGA, BET, Raman and IR techniques. The Raman and IR spectra provided complementary information regarding the structure of the nanocomposite. The Raman spectra were used to identify the crystalline structure of TiO2 in the nanocomposite. In contrast, the IR spectra were used to identify the organic portion of the nanocomposite. The TEM images indicated that the nanocomposites had an average particle size of 6 - 12 nm. In addition, the adsorption and photocatalytic properties of the new material were evaluated. The EPS/TiO2 nanocomposite was efficient at degrading methylene blue (MB) dye solutions under UV irradiation. Furthermore, according to thermal analysis, this material had greater polymer stability due to the incorporation of TiO2.
文摘CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity and photo-catalysis. The synthesized nanocomposites were characterized by BET, UV-VIS, XRD, FE-SEM (EDAX) techniques. X-Ray diffraction (XRD) reveals crystallite size to be 23.22 nm which was calculated using Williamson-Hall (W-H) plot method. The energy of the band gap for CdS/NiS could be thus estimated to be 3.26 eV. The photocatalytic activity of the sample was evaluated by the degradation of textile dye methylene Blue (MB) in aqueous solutions under UV radiation. Hydrogen energy is regarded as a promising alternative in terms of energy conversion and storage. Hydrogen Evolution Reaction (HER) was carried out in both visible light and UV light by using Hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) in the presence of CdS/NiS nanocomposite. The synthesized photocatalyst shows applicable performance for kinetics of Hydrogen Evolution Reaction (HER) in Visible light and UV light. The decomposition of hydrazine (N<sub>2</sub>H<sub>4</sub>H<sub>2</sub>O) proceeded rapidly to generate free hydrogen rich gas through OH radical contact with CdS/NiS nanocomposite at room temperature. The rate of HER is limited by either proton adsorption onto an active site or evolution of formed hydrogen from the surface. A high Tafel slope is indicative of proton adsorption as the rate limiting step, while a lower Tafel slope (20 - 45 mV) indicates that the evolution of molecules hydrogen from the catalyst is rate limiting. In the present case the Tafel slopes for visible light 23.5 mV and 42.5 mV for UV light. Blank experiments show poor activity for HER <em>i.e.</em> 10.1 - 13.5 mV.
基金the National Research Foundation of Korea(No.2022R1A2C3011968).
文摘Recently,MXenes have attracted considerable attention owing to their unique physical and chemical properties.Construction of MXenes to three-dimensional(3D)porous aerogel structures can play a critical role in realizing the profound implications of MXenes,especially for environmental remediation.Nevertheless,developing mechanically robust MXene-based aerogels with reversible compressibility under harsh conditions,such as liquid environments,remains challenging due to the insufficient interfacial strength between MXene nanosheets.Herein,3D porous MXene-based nanocomposite aerogels are developed by dual physical and chemical crosslinking strategy with poly(vinyl alcohol)and formaldehyde in this study.The developed MXenebased nanocomposite aerogels with designed interfacial engineering exhibit outstanding structural stability and extremely high reversible compressibility up to 98%strain as well as unprecedented mechanical durability(2000 cycles at 50%strain)in water environment.Moreover,the aerogels show adaptable compressibility when exposed to different solvents,which is explained with the Hansen solubility parameter.Thanks to their high compressibility in water,the robust MXene-based aerogels exhibit excellent methylene blue adsorption performance(adsorption capacity of 117.87 mg·g^(−1))and superior recycling efficiency(89.48%at the 3rd cycle).The porous MXene-based nanocomposite aerogels are also demonstrated with outstanding thermal insulation capability.Therefore,by synergistically taking their porous structure and super elasticity in liquid environment,the MXene-based aerogels show great promise in diverse applications including adsorption and separation,wastewater purification desalination,and thermal management.
文摘利用磁场作用将金-普鲁士蓝磁性纳米复合物（Au-PB）固定于磁性碳糊电极（MCPE）表面,进而通过金-氨键组装辣根过氧化物酶（HRP）,根据Au-PB与HRP共同催化还原H2O2作用,制备了一种用于过氧化氢检测的修饰电极（MCPE/Au-PB/HRP）.利用循环伏安法（CV）和电化学交流阻抗谱（EIS）对电极的修饰过程进行了表征,初步研究了MCPE/Au-PB/HRP对不同浓度H2O2的响应性能,其检测灵敏度为42.28 m V/decade,线性响应范围为3.53×10-6～3.53×10-3M,相关系数为0.998 6,检测下限为1.96×10-6M.所制备的修饰电极响应迅速、灵敏度高、检测范围较宽,适用于微量H2O2的快速检测,为有机磷农药传感器的制备奠定了基础.
