多孔α-Mn2O3的制备及其催化过一硫酸盐降解亚甲基蓝溶液的性能

采用草酸盐热分解法制得由微米板堆垛而成的呈无规则颗粒状形貌的多孔α-Mn₂O₃,探索其作为催化剂活化过一硫酸盐（PMS）降解模拟染料废水亚甲基蓝（MB）溶液的性能。系统考察催化剂的煅烧温度、催化剂投加量、PMS用量和阴离子种类等工艺参数对锰氧化物催化PMS降解MB溶液的影响。结果表明：450℃煅烧温度下所获产物表现出最为优异的活化PMS的能力,α-Mn₂O₃/PMS体系对MB的降解率达75.88%,而单一PMS或α-Mn₂O₃对MB的降解率仅为22.19%和5.72%。该催化体系降解500 mL浓度为10 mg/L的MB溶液的优化实验参数为：PMS（0.1 mol/L）用量为3 mL,催化剂投加量为0.05 g,反应50 min后MB的降解率可达83.55%。反应体系中引入C₂O₄^2-或PO₄^3-后会对MB溶液的降解产生抑制作用,抑制率分别为49.11%和10.27%,但Cl^-的存在对MB降解无影响。此外,借助淬灭实验和电子顺磁共振技术（EPR）对反应体系中存在的活性物种进行鉴定,α-Mn₂O₃催化PMS可产生·OH,SO₄^-·,·O₂^-和单线态氧（¹O₂）,且¹O₂是参与直接氧化降解MB的最主要活性中间体。动力学分析表明,α-Mn₂O₃催化活化PMS对MB溶液的降解为二级反应,反应速率常数为3.53 L·mmol^-1·min^-1。     

Au纳米粒子表面等离子共振效应(SPR)增强Au/Bi2WO6异质纳米结构的光催化活性

采用水热-光还原法在三维Bi₂WO₆的二级结构纳米片表面原位沉积Au纳米粒子(Au NPs), 成功获得了具有可见光响应活性的Au/Bi₂WO₆异质光催化剂, 并借助XRD、FE-SEM、HR-TEM、XPS和 UV-Vis-DRS谱等手段对其物相组成、形貌和光吸收特性进行表征, 以罗丹明B(RhB)和苯酚为模型污染物对其光催化性能进行研究。实验结果表明, 与纯Bi₂WO₆相比, 所得Au/Bi₂WO₆异质纳米结构对染料降解具有较高的活性, 当Au负载量为1.5at%时, Au/Bi₂WO₆复合催化剂的催化活性最好, 其光催化降解RhB和苯酚的表观速率常数分别是纯Bi₂WO₆的1.5倍和2.2倍。自由基捕获实验表明, 光生空穴(h⁺)和∙O₂^-是RhB在Au/Bi₂WO₆催化材料上光催化降解的主要活性物种。机理分析表明, Au/Bi₂WO₆活性增强归因于光生电子从Bi₂WO₆的导带向AuNPs表面迁移, 降低光生电子-空穴对的复合率, 同时, Au NPs 的等离子共振效应(SPR)拓展了催化剂在可见光区的响应范围, 从而显著提高了Au/Bi₂WO₆异质光催化的剂活性。Au NPs修饰Bi₂WO₆异质催化剂光太阳能驱动在污水处理方面具有潜在应用。     

N掺杂TiO2纳米纤维高可见光催化CO2合成甲醇

采用气相生长法在介孔SiO₂球的表面上制备了ϕ 8~10 nm的TiO₂纳米纤维, 采用相同的方法, 还成功地制备了氮掺杂的TiO₂(N-TiO₂) 纳米纤维, 它具有更高的可见光催化活性。采用X射线光电子能谱(XPS)、紫外光电子能谱(UPS)、X射线衍射(XRD)、扫描电镜(SEM)、透射电子显微镜(TEM)、紫外–可见分光光度计(UV-Vis)、荧光分光光度计(PL)等对样品进行了测试分析。TiO₂纳米纤维具有高结晶度的锐钛矿晶型, 掺氮后的TiO₂纳米纤维带隙变窄, 在可见光波段有明显的吸收, 同时, 光生电子还原能力更强, 大大提高了可见光下催化还原CO₂合成甲醇的产率。在300 W氙灯光照2 h后, 用纯TiO₂纤维催化CO₂合成甲醇, 产率为493.4 μmol•g^-1∙h^-1, 转换频率(TOF) 为0.089 h^-1; 以N-TiO₂为催化剂合成甲醇产率提高了40.1%, 达695.1 μmol∙g^-1∙h^-1, 转换频率(TOF) 提高了40.4%, 为0.125 h^-1。     

钴/锌双金属多孔氧化物的制备及其活化过一硫酸盐降解亚甲基蓝的性能

采用草酸盐-热解法制备钴/锌双金属多孔氧化物复合材料，并用于催化过一硫酸盐(PMS)处理亚甲基蓝(MB)溶液。以Co(NO₃)₂·6H₂O和Zn(NO₃)₂·6H₂O为金属离子源，草酸为沉淀剂，Co²⁺和Zn²⁺同步沉淀获得钴锌草酸盐前驱体，将草酸盐热解后获得具有不同Co/Zn摩尔比的多孔Co₃O₄/ZnO复合氧化物催化剂。结果表明：Co/Zn原料比为1∶5的复合材料(Co₁Zn₅)催化活性最佳，在催化剂用量和PMS浓度分别为0.02 g·L^-1和0.6 mmol·L^-1时，其对MB溶液的降解率可达98.49%。电子顺磁共振(EPR)测试结果表明，Co₁Zn₅/PMS催化氧化体系对MB的降解遵循自由基和非自由基双重机理。Co₁     

锰氮共掺杂稻壳生物炭活化过二硫酸盐降解酸性橙

为了更好地处理水环境中的偶氮染料(酸性橙，AO7)污染问题，以稻壳、尿素和锰盐为原料，通过热解法制备Mn、N共掺杂生物炭复合材料(Mn-N-BC)，活化过二硫酸盐(PDS)降解酸性橙(AO7)染料废水。考察了AO7初始浓度、PDS浓度、催化剂投加量、初始pH值等因素对AO7去除率的影响。结果显示：Mn-N-BC/PDS体系对AO7染料具有较高的去除率，在30 min内可达为98.6%，其表观速率常数k_obs为0.125 min^-1；并且对水环境中的无机阴离子表现出较高的抗性。在3次循环利用后，AO7的去除率仍在75%左右，表明Mn-N-BC对有机污染物的去除具有较高的可重复利用性和稳定性。自由基淬灭研究、XPS分析表明：Mn-N-BC/PDS体系中AO7的降解机制包括自由基途径(·OH、SO₄^-·)和非自由基途径(O₂^-·、¹O₂和电子转移)，其中非自由基途径为主要作用。     

硅藻土/g-C3N4复合材料的制备及其可见光增强活性

采用浸渍-焙烧法制备了具有可见光响应活性的硅藻土/g-C₃N₄复合光催化材料。利用TG、XRD、FE-SEM、HR-TEM、FT-IR、XPS、UV-Vis-DRS 和 PL谱等手段对其物相组成、形貌和光吸收特性进行表征。以RhB的光催化降解为探针反应评价催化剂的活性。光催化结果表明, 2.32wt%硅藻土/g-C₃N₄复合材料对RhB有较高的催化活性, 光催化降解的速率常数是纯g-C₃N₄的1.9倍。自由基捕获实验表明, ·O₂^-是RhB在硅藻土/g-C₃N₄复合材料上光催化降解的主要活性物种。光催化活性提高的主要原因在于硅藻土和g-C₃N₄之间静电作用有利于光生电子-空穴在g-C₃N₄表面的迁移, 进而提高g-C₃N₄的光催化活性。     

MoS2催化活化单过硫酸盐降解有机污染物研究现状

随着城镇化进程加快,大量含难降解有机污染物的工业废水和生活污水因不合理处置而进入水体,对水环境质量造成严重威胁。过渡金属离子催化活化单过硫酸盐(PMS)产生活性氧去除水中难降解有机物的催化体系的研究已有大量文献报道,但存在金属离子二次污染和催化剂难以回收等问题。MoS₂作为优异的二维半导体材料,在储能和催化领域颇具优势并实现产业化生产。在水处理领域,研究发现MoS₂作为非均相金属催化剂能够有效活化PMS去除水中难降解有机物。本文主要综述了MoS₂作为催化剂、金属离子助催化剂或复合型共催化剂活化PMS体系降解水中有机污染物的研究进展,归纳并比较上述催化体系对污染物的降解效能,对催化反应机制进行探讨分析,并针对目前存在的问题提出相关研究展望。      

Bi2O3修饰的BiPO4纳米棒复合催化剂可见光光催化性能的研究

以Bi₂S₃纳米棒为模板合成了形貌可控的BiPO₄ 纳米棒复合光催化剂。在可见光辐射下, 该复合催化剂表现出优异的光催化降解亚甲基蓝(MB)的性能。UV-Vis漫反射谱结果表明: 催化剂经过Bi₂O₃修饰后对可见光有很好吸收; X射线衍射仪和透射电镜等表征结果表明, 所制备的BiPO₄ 纳米催化剂为直径约30 nm、长约200~500 nm的纳米棒。表面修饰少量Bi₂O₃可明显促进光催化剂对亚甲基蓝(MB)的可见光降解效率, 其活性是未修饰催化剂的1.7倍。光电流和N₂吸附实验也表明表面修饰后的催化剂光电流和BET比表面积都明显增加。这可能是由于表面修饰的Bi₂O₃不仅显著提高了BiPO₄ 纳米棒复合催化剂的可见光吸收, 而且在BiPO₄表面起到了富集电子和传输电子的作用。结果表明表面修饰Bi₂O₃的BiPO₄ 纳米棒是一种高活性的光催化材料。     

MoS2@TiO2/CNFs复合材料活化PMS快速去除有机污染物的研究

MoS₂能否高效激发过硫酸盐(PMS)产生高氧化性的过硫酸根基，很大程度上取决于MoS₂纳米片上活性边缘的数量。将MoS₂纳米片垂直生长在TiO₂基底上，能够充分暴露MoS₂的活性位点。通过静电纺丝、碳化和水热法成功地在TiO₂碳纤维上近垂直生长MoS₂纳米片，得到MoS₂@TiO₂/CNFs复合材料。在光照条件下，MoS₂@TiO₂/CNFs复合材料活化PMS后，对亚甲基蓝(MB)的降解率达到97.1%,比仅使用MoS₂@TiO₂/CNFs的催化体系降解速率提升4倍。连续循环5次后，降解率仍能保持在84.8%。以上结果说明MoS₂@TiO₂/CNFs复合材料具有优异的光催化性能和较高的稳定性。     

Fe(III)/rGO/Bi2MoO6复合光催化剂制备及光催化芬顿协同降解苯酚

光催化-芬顿技术耦合可高效降解有机污染物。本研究采用溶剂热法制备了Fe(III)掺杂rGO/Bi₂MoO₆复合催化剂(Fe(III)/rGO/Bi₂MoO₆), 通过外加H₂O₂构建了光催化-芬顿协同体系, 可见光照射3 h后对苯酚的降解率(82%)远高于单独光催化(18%)或芬顿反应(48%), 进一步优化条件对苯酚可实现完全降解。这主要是通过Fe得失电子实现价态的转变, 并以此作为桥梁实现光催化-芬顿的协同作用。同时石墨烯的优异导电性能不仅克服了光催化中光生电子空穴难以分离的问题, 而且促进了Fe³⁺/Fe²⁺的循环反应, 促使芬顿反应产生更多的羟基自由基(?OH), 进一步提高了苯酚的降解效率。实验考察了Fe(III)含量、催化剂投加量、H₂O₂含量以及pH等因素对协同降解效果的影响。淬灭实验证明?OH是协同降解体系中最主要的活性物种, ?O₂^-和h⁺对降解活性也会产生一定的影响, 结合实验结果提出了Fe(III)/rGO/Bi₂MoO₆光催化-芬顿协同降解苯酚的机理。     

Diatomite supported nano zero valent iron with 3D network for peroxymonosulfate activation in efficient degradation of bisphenol A

Diatomite supported nano zero valent iron (nZVI) catalyst (NDA) with complex network structure was prepared via a mild reduction precipitation method in this work.The pore structure and pore distribu-tion of NDA can be regulated and controlled through adjusting the loading amount of nZVI.In general,the nano three-dimensional network formed by nZVI and diatomite channels greatly increase the specific surface area and pore volume of NDA,and further formed more active sites,which made NDA have better performance in activating PMS to degrade BPA than pure nZVI.The pseudo-first-order reaction rate con-stant of 50-NDA (50％-nZVI/diatomite) is almost 3 times higher than that of pure nZVI.Besides,the elec-tron paramagnetic resonance (EPR) and radical quenching experiments showed that the activation process was dominated by the sulfate radical (SO4·-) and hydroxyl radical (OH) produced by Fe0 oxidation.The generated electrons promote the self-decomposition of PMS to produce singlet oxygen (1O2),and then the valence state of iron changes to produce free radicals.In addition,the possible degradation pathway of BPA was inferred from the intermediate products identified by liquid chromatograph-mass spectrom-eter (LC-MS).This study provides a novel strategy for the design and preparation of three-dimensional composite catalysts derived from natural mineral.     

Nitrogen‐Coordinated Single Cobalt Atom Catalysts for Oxygen Reduction in Proton Exchange Membrane Fuel Cells

Due to the Fenton reaction, the presence of Fe and peroxide in electrodes generates free radicals causing serious degradation of the organic ionomer and the membrane. Pt‐free and Fe‐free cathode catalysts therefore are urgently needed for durable and inexpensive proton exchange membrane fuel cells (PEMFCs). Herein, a high‐performance nitrogen‐coordinated single Co atom catalyst is derived from Co‐doped metal‐organic frameworks (MOFs) through a one‐step thermal activation. Aberration‐corrected electron microscopy combined with X‐ray absorption spectroscopy virtually verifies the CoN₄ coordination at an atomic level in the catalysts. Through investigating effects of Co doping contents and thermal activation temperature, an atomically Co site dispersed catalyst with optimal chemical and structural properties has achieved respectable activity and stability for the oxygen reduction reaction (ORR) in challenging acidic media (e.g., half‐wave potential of 0.80 V vs reversible hydrogen electrode (RHE). The performance is comparable to Fe‐based catalysts and 60 mV lower than Pt/C ‐60 μg Pt cm^?2). Fuel cell tests confirm that catalyst activity and stability can translate to high‐performance cathodes in PEMFCs. The remarkably enhanced ORR performance is attributed to the presence of well‐dispersed CoN₄ active sites embedded in 3D porous MOF‐derived carbon particles, omitting any inactive Co aggregates.     

Li1+xCoyMn2-x-yO4的结构及电化学性能研究

利用溶液相合成技术把钴掺入到主尖晶石相中制得掺钴尖晶石相材料。所合成的材料具有颗粒分布均匀及结晶性能好等特点。利用X射线粉末衍射仪、傅里叶变换红外分光光度计及扫描电子显微镜对所合成掺杂锂材料的结构性能进行表征。研究表明掺杂钴可提高材料的结构稳定性能，减少锰在电解液中溶解，减少锂离子在材料中迁移电阻。电化学性能测试结果表明所合成掺钴材料Li1.03Co0.05Mn1.92O4具有较好的初始容量及循环稳定性能。     

Enhanced photocatalytic activity of ZnO/CuO nanocomposite for the degradation of textile dye on visible light illumination

The photocatalytic degradation of organic dyes such as methylene blue and methyl orange in the presence of various percentages of composite catalyst under visible light irradiation was carried out. The catalyst ZnO nanorods and ZnO/CuO nanocomposites of different weight ratios were prepared by new thermal decomposition method, which is simple and cost effective. The prepared catalysts were characterized by different techniques such as X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and UV–visible absorption spectroscopy. Further, the most photocatalytically active composite material was used for degradation of real textile waste water under visible light illumination. The irradiated samples were analysed by total organic carbon and chemical oxygen demand. The efficiency of the catalyst and their photocatalytic mechanism has been discussed in detail.     

Li1+xCoyMn2-x-yO4的结构及电化学性能研究

利用溶液相合成技术把钴掺入到主尖晶石相中制得掺钴尖晶石相材料.所合成的材料具有颗粒分布均匀及结晶性能好等特点.利用X射线粉末衍射仪、傅里叶变换红外分光光度计及扫描电子显微镜对所合成掺杂锂材料的结构性能进行表征.研究表明掺杂钴可提高材料的结构稳定性能,减少锰在电解液中溶解,减少锂离子在材料中迁移电阻.电化学性能测试结果表明所合成掺钴材料Li_1.03Co_0.05Mn_1.92O₄具有较好的初始容量及循环稳定性能.     

Sulfur and Nitrogen Co‐Doped Graphene for Metal‐Free Catalytic Oxidation Reactions

Sulfur and nitrogen co‐doped reduced graphene oxide (rGO) is synthesized by a facile method and demonstrated remarkably enhanced activities in metal‐free activation of peroxymonosulfate (PMS) for catalytic oxidation of phenol. Based on first‐order kinetic model, S–N co‐doped rGO (SNG) presents an apparent reaction rate constant of 0.043 ± 0.002 min^?1, which is 86.6, 22.8, 19.7, and 4.5‐fold as high as that over graphene oxide (GO), rGO, S‐doped rGO (S‐rGO), and N‐doped rGO (N‐rGO), respectively. A variety of characterization techniques and density functional theory calculations are employed to investigate the synergistic effect of sulfur and nitrogen co‐doping. Co‐doping of rGO at an optimal sulfur loading can effectively break the inertness of carbon systems, activate the sp²‐hybridized carbon lattice and facilitate the electron transfer from covalent graphene sheets for PMS activation. Moreover, both electron paramagnetic resonance (EPR) spectroscopy and classical quenching tests are employed to investigate the generation and evolution of reactive radicals on the SNG sample for phenol catalytic oxidation. This study presents a novel metal‐free catalyst for green remediation of organic pollutants in water.     

CuO/CeO2 catalysts prepared with different cerium supports for CO oxidation at low temperature

The activity of a catalyst depends on the nature of its support, its active site, and its preparation method. This study aimed to employ various types of CeO₂ supports such as commercial CeO₂ and self-prepared CeO₂ for the preparation of copper catalysts. The CuO/CeO₂ catalysts were prepared using the polyol process and impregnation method. The catalysts were characterized using Brunauer–Emmett–Teller analysis, scanning electron microscopy, and X-ray analysis, and their catalytic activity for CO removal was evaluated in a microcatalytic reactor. The experimental results showed that the catalytic activity of the CuO/CeO₂ catalysts with different calcination temperatures decreased in the following order: 500 °C > 300 °C > 700 °C. Compared to the impregnation method, the polyol process generated well-dispersed metal particles over the support and showed higher CO removal efficiency with low activation energy. Compared to CuO/CeO₂ catalysts with commercial CeO₂, those with CeO₂ that was self-prepared by pyrolysis had a large pore volume and good crystal structure of CeO₂ and showed good performance. The catalytic activity for CO removal was in the following order: CuO/CeO₂-P (pyrolysis) > CuO/CeO₂-C (commercial) > CuO/CeO₂-D (deposition precipitation). CuO/CeO₂-P catalysts showed good activity even at low temperature. The CuO/CeO₂-P(300)-P-120 min catalyst was found to possess the good CO removal rate when the oxygen content was 6%, CO concentration was 500 ppm, catalyst weighed 1.0 g, pollutant gas velocity was 500 mL min⁻¹, SV was 3.7 × 10⁴ h⁻¹, and reaction temperature was 150 °C.     

酸处理对FeN/ZIF-8催化剂氧还原反应催化性能的影响

研发高性能、低成本的非贵金属阴极氧还原反应催化剂是目前质子交换膜燃料电池的主要研究方向之一。以1, 10-菲啰啉为氮源, FeSO₄·7H₂O为铁源, 考察以ZIF-8为载体制备的FeN/ZIF-8催化剂的氧还原反应催化性能, 并探究酸处理对FeN/ZIF-8催化剂结构及性能的影响。通过X射线衍射、比表面积和孔径分布测试、透射电子显微镜等物理表征手段对催化材料进行结构表征, 使用旋转圆盘电极对催化剂氧还原反应催化活性和稳定性进行测试。结果表明: 以ZIF-8为载体制备的催化剂含有Fe₃C, 以及具有较大的比表面积, 这可能是催化剂具有较高氧还原反应初始催化活性的原因。酸处理可去除催化剂中部分不稳定的含铁碳化物和无序碳结构, 使催化剂具有更大的比表面积、更丰富的介孔结构和更高的孔体积; 同时, 酸处理可提高碳基体的耐腐蚀性, 在老化测试中维持催化剂所具有的较高比表面积和丰富的介孔结构, 从而使FeN/ZIF-8-A催化剂表现出更好的氧还原反应活性和稳定性。     

太阳光下Cr~(3+)掺杂TiO_2复合微粒光催化性能研究

利用酸催化的溶胶一凝胶法成功地合成了一系列不同CP3+掺杂量(x=0.01%～10%)的TiO2复合光催化剂(Cd3+/TiO2).在太阳光条件下,以亚甲基蓝溶液的光催化降解对复合材料的光催化性能进行了表征,并考察了催化剂投加量、Cr3+掺杂量和溶液pH值等因素对光催化降解反应的影响.结果表明,亚甲基蓝溶液在复合微粒上的光催化降解反应遵循Langmuir-Hinshelwood动力学模型,在催化剂投加量为lg/L、Cr3+掺入量为0.3%和pH=7时,Cr3+/TiO2复合微粒光催化活性达最佳,测得表观反应速率常数 K为7.27×10-3 rag(L·min)-1,t1/2为95min,反应4h后亚甲基蓝的降解率可达79%,与纯的TiO2相比较,反应速率提高了2倍,降解率提高了20%.中性或碱性条件下有利于亚甲基蓝溶液的光催化降解.     

可磁分离回收多孔CoFe_(2)O_(4)的制备及其催化过一硫酸盐降解亚甲基蓝溶液的性能EI北大核心CSCD

采用草酸盐热解法制得Fe_(2)O_(3),Co_(3)O_(4)以及CoFe_(2)O_(4)三种过渡金属氧化物多孔材料。借助XRD,SEM,BET,VSM和XPS等测试手段对材料的晶体结构、微观形貌、比表面积、磁学性能以及表面化学状态进行分析。选择典型的阳离子型染料亚甲基蓝(MB)作为降解模型,对三种样品催化活化过一硫酸盐(PMS)降解处理模拟印染废水的性能进行评价。结果表明:三种材料均具有分级微/纳米纤维状多孔结构,CoFe_(2)O_(4)因具有最大的比表面积以及Fe,Co元素间的协同效应比Fe_(2)O_(3)和Co_(3)O_(4)表现出更为优异的催化PMS降解MB溶液的性能。通过单因素实验,确定出CoFe_(2)O_(4)/PMS体系降解500 mL浓度为10 mg·L^(-1)MB溶液的优化条件为:PMS用量3 mL(0.1 mol·L^(-1)),催化剂添加量0.07 g,反应时间50 min。在此条件下,MB的降解去除率为89.77%。考察几种阴离子对CoFe_(2)O_(4)/PMS催化氧化体系的影响,发现Cl^(-),PO_(4)^(3-),C_(2)O_(4)^(2-)的存在均对MB的降解有一定的抑制作用。活性物种猝灭实验和电子顺磁共振(EPR)鉴定结果证实,^(1)O_(2)是CoFe_(2)O_(4)/PMS催化氧化体系中产生的最主要活性物种。循环使用实验结果表明,CoFe_(2)O_(4)具有较好的稳定性,且可磁分离回收特性使其可作为活化PMS降解印染废水的候选催化材料。