Photocatalytic degradation of Acid Blue 62 over CuO-SnO2 nanocomposite photocatalyst under simulated sunlight

The novel CuO-SnO2 nanocomposite oxide photocatalysts were prepared by simple co-precipitation method, and characterized by X- ray diffraction, transmission electron microscopy, N2 adsorption-desorption measurement and UV-Vis diffuse reflectance spectroscopy. The photocatalytic activities of CuO-SnO2, evaluated using the photodegradation of Acid Blue 62 as a probe reaction under the irradiation of Xenon light, were also found to be related to the calcination temperature and the molar ratio of Cu to Sn. The maximum photocatalytic activity of the CuO-SnO2 photocatalyst was observed to be calcined at 500~C for 3 h （the molar ratio of Cu to Sn was 1：1） due to the sample with good crystallization and high surface area. It also showed much higher photocatalytic activity in treatment dye wastewater under simulated sunlight irradiation compared to Degussa P25 TiO2.     

C3N4/BiOBr复合可见光催化剂的性能及其作用机制

利用水热合成法制备了C_3N_4/BiOBr复合可见光催化剂,通过XRD、FT-IR、SEM、DRS、PL等手段对催化剂的物相组成和光化学性能进行了系统表征,利用对罗丹明B(RhB)的降解实验评价了催化剂在可见光照下的光催化降解活性和稳定性并通过ESR分析和自由基捕获实验探究了RhB的光催化降解机制.结果表明,水热合成法可成功制备结晶性能良好的C_3N_4/BiOBr复合可见光催化剂;C_3N_4的复合降低了BiOBr光催化剂的电子-空穴的复合,提高了光催化降解活性,其中15%C_3N_4/BiOBr的活性最佳,可见光照18 min后RhB的脱色率达100%,较纯BiOBr提高了1.5倍,且重复使用5次后仍具有较高的光催化降解活性;复合催化剂光催化降解RhB过程中参与降解的主要活性物种为空穴(h~+)和超氧自由基(·O_2~-),其中h~+影响更为显著.     

Fe~(3+)掺杂TiO_2/凹凸棒复合材料的光催化性能

采用酸催化的溶胶-凝胶法制备了一系列Fe3+掺杂TiO2/凹凸棒(Fe3+-TiO2/ATP)复合光催化剂材料。在可见光条件下,以亚甲基蓝(MB)溶液的光催化降解反应,评价了样品的光催化性能,研究了TiO2负载量、Fe3+掺杂量和焙烧温度对复合材料光催化性能的影响。在单因素实验的基础上,采用正交实验设计(L25(53))优化了催化剂的制备条件。光催化实验结果表明,MB在复合材料上的光催化降解反应遵循Langmuir-Hinshelwood(L-H)动力学模型。正交实验结果表明,当TiO2负载量为15%、Fe3+掺杂量为0.5%和焙烧温度为550℃时,得到的复合材料对MB的光催化降解效率最佳,测得表观反应速率常数kapp为6.09×10-3min-1,反应4 h后MB的降解率(Dt)可达75.88%,相同实验条件下与P25(1.51×10-3min-1)相比较,反应速率提高了4.03倍,降解率提高了45.05%。另外,复合材料的沉降性能优于P25,易于分离,是一类有应用前景的复合光催化剂。     

Bi（25）FeO40-g-C3N4磁性催化剂的制备及其可见光催化性能

采用水热法制备了铁酸铋(Bi25FeO40),将其与类石墨相氮化碳(g-C3N4)复合得到Bi25FeO40-g-C3N4磁性光催化剂,用X-射线衍射(XRD)、扫描电子显微镜(SEM)、BET比表面积分析、UV-Vis光谱和磁滞回线对该磁性光催化剂进行了表征.考察了Bi25FeO40-g-C3N4复合催化剂对亚甲基蓝的可见光催化降解效果.结果表明,Bi25FeO40-g-C3N4复合催化剂对亚甲基蓝的可见光催化降解效率远高于Bi25FeO40.此外,Bi25FeO40-g-C3N4表现出顺磁性,可通过磁选分离并回收.     

电气石球负载纳米二氧化钛光催化剂的制备及其对水中邻苯二甲酸酯的降解作用

以电气石微球为载体,采用溶胶–凝胶法制备电气石负载纳米二氧化钛(TiO_2)光催化材料。用X射线衍射分析、扫描电镜对微球负载TiO_2光催化剂的晶型结构和形貌进行了表征。以6种邻苯二甲酸酯为降解对象,考察了热处理温度、辐射强度对TiO_2光催化活性的影响。发现TiO_2以纳米颗粒的形式牢固负载在电气石微球表面;以天然电气石微球为载体所制得的TiO_2光催化剂对于6种邻苯二甲酸酯具有较好的光催化降解效果。     

One-step synthesis of N-doped metal/biochar composite using NH3-ambiance pyrolysis for efficient degradation and mineralization of Methylene Blue

A series of new biochar-supported composite based on the combination of biochar and metallic nanoparticles(NPs)were produced through single-step pyrolysis of FeCl_3–Ti(OBu)_4 laden agar biomass under NH_3 environment.The physiochemical properties of composites were characterized thoroughly.It has found that heating temperature and N-doping through NH_3-ambiance pyrolysis significantly influence the visible-light sensitivity and bandgap energy of composites.The catalytic activities of composites were measured by degradation of Methylene Blue(MB)in the presence or absence of H_2O_2 and visible-light irradiation.Our best catalyst(N–TiO_2–Fe_3O_4-biochar)exhibits rapid and high MB removal competency(99.99%)via synergism of adsorption,photodegradation,and Fenton-like reaction.Continuous production of O_2U~-and UOH radicles performs MB degradation and mineralization,confirmed by scavenging experiments and degradation product analysis.The local trap state Ti~(3+),Fe_3O_4,and N-carbon of the catalyst acted as active sites.It has suggested that the Ti~(3+)and N-doped dense carbon layer improve charge separation and shuttle that prolonged photo-Fenton like reaction.Moreover,the catalyst is highly stable,collectible,and recyclable up to 5 cycles with high MB degradation efficiency.This work provides a new insight into the synthesis of highly visible-light sensitized biocharsupported photocatalyst through NH_3-ambiance pyrolysis of NPs-laden biomass.     

BiOCl-(NH4)3PW12O40复合光催化剂制备及其光催化降解污染物机制

光生电子和空穴的分离效率是影响光催化性能的重要因素.氯氧铋是典型的层状纳米光催化剂,却因光生电子和空穴的快速复合所表现出的低量子效率而受到使用限制.本文通过两步的水热法合成了BiOCl-(NH_4)_3PW_(12)O_(40)复合光催化剂.以甲基橙(MO)为模拟污染物进行光催化活性测试.结果表明,在氙灯模拟的太阳光照射下,Bi与W的原子比为1∶1时,其催化效果最佳.通过自由基猝灭实验对催化剂光降解MO的催化机制进行了研究,发现BiOCl是由空穴,羟基自由基和超氧自由基共同作用来对MO进行降解;而复合催化剂则主要以羟基自由基和超氧自由基为活性物种来降解MO.通过对反应前后的催化剂进行XPS分析,证明了磷钨酸铵可以接收BiOCl产生的光生电子.通过光电流测试,表明复合光催化剂的光生电子的转移和分离效率有了较大的提高,从而提高了光催化活性.     

氮化碳增强Ag/AgI/γ-Al2O3的可见光催化性能及其机理

通过热聚合的方法使氮化碳(CN)与Ag/AgI/γ-Al_2O_3发生耦合作用,制备出CN-Ag/AgI/γ-Al_2O_3可见光催化剂.采用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)和紫外可见漫反射光谱(UV-vis DRS)等方法对合成的样品进行了表征,并通过可见光下甲基橙(MO)的降解实验探究了CN对Ag/AgI/γ-Al_2O_3光催化活性及稳定性的影响.结果表明,CN的掺杂改变了Ag纳米颗粒的形状与粒径,且Ag、AgI与CN之间形成强相互作用.与Ag/AgI/γ-Al_2O_3相比较,在可见光波长分别为λ420、450和510 nm时,CN-Ag/AgI/γ-Al_2O_3对MO具有更高的催化降解效率,光反应30 min后,MO的去除率分别为97%、97%和93%.同时,CN的加入显著地增加了Ag/AgI/γ-Al_2O_3的稳定性,抑制了反应过程中Ag~+的释放量,而且反应前后CN-Ag/AgI/γ-Al_2O_3样品的结构没有明显的变化.其活性和稳定性提高的主要原因是CN加速了电子由MO传递至Ag纳米颗粒的过程,同时Ag颗粒等离子体共振(plasmon)效应的增强也有利于MO的催化降解.不同自由基捕获剂的影响实验表明,O_2~(·-)和h~+是反应体系的主要活性物种.     

Graphitic carbon nitride-based photocatalysts in the applications of environmental catalysis

Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution problems. The key issue is the development of high-efficiency photocatalysts. Various strategies in the state-of-the-art advancements, such as heterostructure construction, heteroatom doping, metal/single atom loading, and defect engineering, have been presented for the graphitic carbon nitride (g-C₃N₄)-based nanocomposite catalysts to design their surface chemical environments and internal electronic structures to make them more suitable for different photocatalytic applications. In this review, nanoarchitecture design, synthesis methods, photochemical properties, potential photocatalytic applications, and related reaction mechanisms of the modified high-efficiency carbon nitride-based photocatalysts were briefly summarized. The superior photocatalytic performance was identified to be associated with the enhanced visible-light response, fast photoinduced electron-hole separation, efficient charge migration, and increased unsaturated active sites. Moreover, the further advance of the visible-light harvesting and solar-to-energy conversions are proposed.     

室内污染物甲醛的光催化去除实验

为了分析流速、湿度、温度对室内污染物甲醛的光催化氧化影响,在搭建光催化氧化分析动态实验台的基础上,利用浸渍准膜法制得TiO2光催化剂薄膜,并进行甲醛的光催化去除实验。结果表明,随着流速的增加,污染物的光催化氧化逐步由传质控制过程过渡到光催化氧化控制过程,湿度对甲醛的光催化氧化存在一最佳范围,温度对甲醛的光催化氧化无明显影响。