不同形貌TiO2对氯霉素的光催化降解研究

将浓碱水热法制备的钛酸盐纳米管(TNT),采用二次水热和高温煅烧法制备了不同形貌的锐钛矿相TiO2纳米管(NT)和TiO2纳米棒(NB)光催化剂,通过XRD、TEM、UV-vis漫反射吸收光谱(DRS)对产物进行表征,研究光催化剂对氯霉素的光催化降解性能。结果表明,不同形貌TiO2光催化剂对氯霉素具有不同的催化活性,TiO2纳米管(NT)比TiO2纳米棒(NB)有更好的吸附性能;在高压汞灯辐射下,TiO2纳米棒(NB)对氯霉素的光催化降解效率高于TiO2纳米管(NT)。在高压汞灯下TiO2纳米管(NT)和TiO2纳米棒(NB)对氯霉素的光催化降解过程均遵从Langmuir-Hinshelwood动力学模型。     

扩渗温度对TiO_2 NTs/TC4光催化制氢性能的影响

为了提高TiO_2薄膜光催化活性,采用阳极氧化在TC4钛合金表面制备了TiO_2纳米管阵列。利用扫描电镜、X-射线衍射、拉曼谱图、X-射线光电子能谱和紫外可见漫反射光吸收对热扩渗后的阳极化膜层的微观结构进行表征。结果表明:在TC4钛合金的α和β相,氧化膜呈不同的形貌,α相区域纳米管的孔径约为50 nm,β相区域只形成了不规则、大小不均的1~10 nm的小孔。氧化物中V离子的存在对锐钛矿相的生成具有抑制作用,扩渗θ在500和600℃时,膜层中存在少量结晶度不高锐钛矿与金红石相并存的晶体结构。吸附在阳极化膜层表面的碳化物含有石墨相,碳修饰TiO_2纳米管列在可见光区域有很强的光响应区间。在600℃扩渗温度下得到的具有部分石墨化的C修饰V掺杂的TiO_2NTs光催化活性最高,膜层产氢速率为21.25μmol/h。     

光催化制氢催化剂TiO_2改性研究进展

文章概述了光催化制氢催化剂TiO2改性研究进展。根据国内外最近研究,重点描述了TiO2的改性方面:贵金属沉积、金属离子掺杂、非金属元素掺杂、染料敏化、晶面控制及半导体复合等的最新研究情况,阐述了该课题的意义和今后的研究方向。     

Pd/WS2二维复合材料的制备及电解水制氢性能研究

首先通过锂离子插层制备了薄层WS_2纳米片,并采用软模板法在纳米片上负载了Pd纳米颗粒,得到Pd/WS_2复合材料。X射线衍射光谱(XRD)和透射电子显微镜(TEM)的结果表明Pd颗粒均匀地负载在了WS_2纳米片上。随后在H_2SO_4水溶液中对该复合材料进行电解水析氢性能测试,线性扫描伏安法(LSV)结果表明:复合材料的析氢起始电位为155 mV,塔菲尔斜率为121.79 mV·dec~(-1),总体催化性能相比于单纯的WS_2纳米片和Pd金属颗粒有很大的改善,也优于当前商用的Pd/C催化剂。采用循环伏安法(CV)测试其稳定性,结果表明Pd/WS_2复合物电极具有优良的电催化析氢稳定性。     

纳米TiO2光催化产氢的研究进展

介绍了纳米TiO2光催化产氢的基本原理和特点,重点综述了国内外提高纳米TiO2光催化产氢的最新方法.指出未来光催化产氢的研究方向主要是高效产氢光催化剂的合成和高效光催化产氢反应器的设计.     

永磁体强化电解水制氢的实现

本实验在磁场驱动强化电解水制氢的可行性的前提下,通过实验结合有效的气液两相流动分析。揭示磁场在电解槽内引发的多种形式的磁对流对电极间气液两相流动驱动机制和气相产物分布规律。最终通过优化外部磁场配置实现磁场强化电解水制氢的高效利用。     

不同基团有机物在二氧化钛上的光催化制氢

采用水热法、溶胶凝胶法和光沉积法在氧化锌表面制备花状二氧化钛催化剂,并利用不同结构有机物制氢。结果表明,制备的二氧化钛具有花状形貌,比表面积大且具有良好的产氢性能。通过用不同结构的醇、醛、羧酸、醚、酮、酯、烷烃及芳香族有机物等制氢发现：有机物的结构对制氢活性的影响较大,苯环结构由于其强稳定性难以被裂解而无法产生氢气。总之,分子与催化剂的氢键吸附作用和羟基对分子的植入效率是决定有机物制氢的两个重要因素,决定着产氢效率。     

锌片基体ZnO纳米棒-纳米片多级阵列结构的制备及其光催化性能研究

采用简单的水热法在锌片基体上获得均匀排列的Zn O纳米棒阵列,在此基础上通过柠檬酸三钠辅助二次生长获得Zn O纳米棒-纳米片多级阵列结构。通过XRD和FE-SEM表征所得Zn O纳米棒和Zn O纳米棒-纳米片多级阵列结构的晶体结构和微观形貌。光催化降解亚甲基蓝溶液的结果表明,与Zn O纳米棒阵列相比,Zn O纳米棒-纳米片多级纳米阵列结构表现出更优异的光催化活性,紫外辐照下其光催化效率达到88.1%。     

醇类在Pt-TiO2纳米管上的光催化制氢

采用溶胶-凝胶法(sol-gel)、水热法和光沉积法制备了铂(Pt)负载量为0.5%的二氧化钛纳米管催化剂(TNT),并利用甲醇等醇类制氢。结果表明,所制备的催化剂具有良好的管状形貌;甲醇(CH₃OH)和水在同等数量级上共同吸附在催化剂表面9 h后制氢效率最高,核磁共振氢谱(¹H NMR)分析表明甲醇裂解制氢过程在催化剂表面进行,因氢键束缚产生的过渡产物无法脱附直至形成CO₂;醇类碳链长度、支链数目、羟基数目以及苯环基团等都对醇类制氢有着不同的影响,制氢过程中醇分子与催化剂的吸附作用强弱和醇分子被羟基植入的难易程度是制氢效果差异的主要原因。     

金红石相含量对混晶纳米TiO2光催化分解水制氢的影响

合成了不同金红石相含量的纳米TiO2,并研究了其光催化分解水制氢的活性.结果表明,未沉积Pt时,纯锐钛矿TiO2活性最高,金红石相含量的增加导致TiO2活性下降并在下降过程中出现波动.沉积Pt后,TiO2产氢速率随金红石相含量的增加先增后减,在金红石相质量分数为9.7%时达到最高,为40.35 mmol/(gcat·h).首次提出了金红石相含量时混晶纳米TiO2光催化分解水制氢活性的影响机理.     

蒙脱石/TiO2复合材料制备及其光催化性能研究

以蒙脱土和钛酸丁酯为原料,采用溶胶凝胶法制备出蒙脱石/TiO2复合材料,利用XRD、SEM、光催化亚甲基蓝溶液对其物相组成、晶体结构、微观结构和光催化性能进行了研究.结果表明:TiO2以锐钛矿相分布于蒙脱石的层间域和表面,并使蒙脱石d001有不同程度的增大.蒙脱石/TiO2复合材料的加入量和Ti/蒙脱石比值、亚甲基蓝溶液的初始质量浓度对蒙脱石/TiO2复合材料的吸附和光催化效率均有影响.     

水电解制氢装置运行及维护

介绍水电解制氢装置的工艺流程,分析其工作原理。并且结合日常运行及维护经验,对水电解制氢装置的日常管理和故障处理进行说明。     

TiO_2纳米管在不同条件光催化降解的活性研究

本文利用阳极氧化法在纯钛片表面制备了TiO2纳米管阵列膜,解决TiO2光催化剂的涂敷固定问题。采用场发射扫描电镜(FESEM)和XRD对制备TiO2纳米管阵列膜的形貌和晶体结构进行表征。结果发现,所制得的纳米管管径70～80nm,壁厚5～10nm,XRD显示经420℃热处理的TiO2纳米管为锐钛矿晶型,经500℃热处理的TiO2纳米管出现金红石晶型。以10mg·L-1的甲基橙溶液为降解物进行光催化试验,分别研究了溶液的初始pH值、TiO2纳米管阵列膜的晶型、TiO2膜的使用次数对降解率的影响。试验结果表明,当溶液初始pH值为1时,TiO2纳米管阵列的光催化性能最好,同时随着TiO2膜使用次数的增加,其光催化效果有所下降。     

Enhanced enzymatic hydrolysis of rice straw pretreated by alkali assisted with photocatalysis technology

BACKGROUND: The fermentable sugars in lignocellulose are derived from cellulose and hemicellulose, which are not readily accessible to enzymatic hydrolysis because of their biological resistance, so that pretreatment of lignocellulose is needed for this process. In this work, a novel lignocellulose pretreatment method using alkali solution assisted by photocatalysis was investigated. RESULTS: The reaction conditions of nano‐TiO₂ dosage and photocatalysis time were optimized at 2 g L^?1 and 1 h, respectively. After pretreatment under these conditions, cellulose in rice straw was increased from 37.5% to 71.5%, and lignin decreased from 18.5% to 9.0%. The results of X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR) and scanning electron microscopy (SEM) analysis showed that the physical properties and microstructure of the straw were changed by this pretreatment, which favored the following enzymatic hydrolysis. The enzymatic hydrolysis rate of the straw pretreated using this technology was verified to be 73.96%, which was 2.56 times higher than that obtained with the alkali procedure. CONCLUSION: The proposed photocatalysis pretreatment technology was more efficient at degrading the lignin and hemicellulose in rice straw than alkali pretreatment, making it more readily available for the following enzymatic hydrolysis process. Copyright © 2009 Society of Chemical Industry     

TiO2光催化氧化有机污染物的研究进展

综述了近年来TiO2光催化反应的机理及其在染料废水处理，制浆造纸废水处理，渗滤液处理，水面有机污染物膜和一般工业废水处理，空气与废水消毒净化中的应用。     

电解水制氢的耐碱离子膜研究进展

碱性离子膜电解水制氢技术具有成本低、环境友好、可使用光伏、风电等波动性电源等优势, 近年来得到广泛关注。作为碱性电解水的核心组件,离子膜对电解槽性能、稳定性及制氢安全起着至关重要的作用。因此,开发具有良好氢氧根传导率、高度耐碱稳定性及优异阻气性的离子膜具有重要意义。本文围绕碱性电解水用离子膜材料开展论述,包含多孔隔膜、溶剂化离子膜和阴离子交换膜三个类别,从氢氧根传导率、耐碱稳定性及电池性能等角度,分析碱性电解水用离子膜的研究进展及所面临的技术难题,从膜结构与膜材料分子设计着手,为研究开发用于碱性电解水的离子膜提供新思路。     

Hydrogen evolution on electrodeposited nickel-cobalt-molybdenum in alkaline water electrolysis

The hydrogen evolution reaction (HER) was conducted on nickel-cobalt-molybdenum electrodes in a 30 wt% KOH solution at temperatures from 298 to 353 K. These nickel- and cobalt-based ternary materials were electrodeposited on a stainless steel screen, initially at a current density of 0.5 A cm⁻² and subsequently at 2 A cm⁻². They showed good adhesion to the substrate, high surface roughness and they enhanced the HER in water electrolyssi compared with nickel, cobalt, nickel-molybdenum and cobalt-molybdenum deposited electrodes, having comparable or even higher deposit loadings. The HER enhancement on the ternary materials with respect to nickel-molybdenum and cobalt-molybdenum was attributable to their large surface area. On the ternary materials, two Tafel slopes were distinguished on the HER polarization in the low and high HER overpotential ranges. However, no conventionally proposed relation between TAfel slope and temperature was found; the transfer coefficient increased with temperature under the experimental conditions.     

质子交换膜水电解制氢膜电极研究进展

质子交换膜水电解（PEMWE）制氢具有可适用于风能太阳能等可再生能源的间歇性和波动性、能量转换效率高、启动快速、占地小等优点,成为目前绿氢制取重点关注的技术。膜电极作为水电解制氢关键核心部件,对于水电解制氢的性能、效率和寿命至关重要,并随着量产规模的扩大在系统成本中的占比越来越高。发展高性能、低成本和高耐久性的膜电极对于绿氢的低成本大规模制取具有重要意义。本文综述了近年来质子交换膜电解水制氢膜电极中质子交换膜、催化层、多孔传输层等关键材料部件以及膜电极制备技术的研究进展和成果,并进行了简要评述。从膜电极设计和开发的角度系统地梳理了如何提高电解制氢性能、降低水电解制氢膜电极成本等方面的进展。最后,就未来膜电极研发的方向提出了建议。     

Antioxidant effects of reduced water produced by electrolysis of sodium chloride solutions

Antioxidant vitamins and enzymes such as superoxide dismutase, catalase and glutathione peroxidase are considered to function as scavengers against reactive oxygen species and to provide protection against reactive oxygen species, including free radicals. Although antioxidants such as L-ascorbic acid, d-catechin and quercetin dehydrate show superoxide dismutation activity, using reduced water produced in the cathode side by electrolysis as a solvent instead of 2 mM NaC1 solution of the same pH level as the reduced water increased the superoxide dismutation activity of these antioxidants. Moreover, neither the reduced water nor its electrolyte solution showed any superoxide dismutation activity by itself. On the other hand, the reduced water was able to decrease hydrogen peroxide levels. It has been found that the behaviour of H₂ in reduced water, which was activated by a platinum electrode, differed from that of H₂ introduced by bubbling of hydrogen gas. The former decreased H₂O₂, whereas the latter did not. These results suggest strongly that the increase in superoxide dismutation activity, with a proton donor such as L-ascorbic acid, is due to an increase in the dissociation activity of water while the scavenging activity for H₂O₂ is due to activated dissolved H₂ in the reduced water.     

Metastability and electrocatalytic activity of ruthenium dioxide cathodes used in water electrolysis cells

Ruthenium dioxide-coated titanium electrodes when used as cathodes in water electrolysis cells are metastable systems which display high catalytic activity and unexpected stability. At the potentials involved the oxide films clearly should undergo reduction; the barrier to the latter process seems to arise due to hydroxylation of the outer layers of the thermally prepared oxide; the reduction of hydrous oxide films in general is inhibited by the intervention (as the primary reduction product) of a high energy state of the metal. The catalysis of the hydrogen gas evolution reaction at the oxide/solution interface is attributed to the involvement of a metastable cyclic redox mediator system involving multivalent Ru(OH)_x surface species.