过氧化钛配合物(PTC)体系在柔性染料敏化太阳能电池中的应用

本文利用水性过氧化钛配合物(peoxotitanium complex:PTC)前驱体可低温合成锐钛矿TiO2溶胶的特性,将其用作柔性染料敏化太阳能电池(DSSC)中的光阳极材料的成膜助剂.研究发现:加入基于PTC制得的TiO2溶胶可以明显提高DSSC的光电转换性能,在制备DSSC的浆料中加入10%(体积分数)的基于PTC制得的TiO2溶胶后,电池的光电效率可以提升50%.我们进一步研究了光电转换效率的影响因素,结果表明,溶胶的加入量和反应时间均有一最佳值,当基于PTC的TiO2溶胶添加量为10%,反应时间为9h,所得到电池的光电性能最好.

低温制备锐钛矿TiO2溶胶水溶液

利用过氧化的方法低温制备锐钛矿相TiO2溶胶水溶液，其制备过程由4个步骤组成：利用新制备的正钛酸沉淀得到过氧化钛溶液；利用氨水溶液沉淀过氧化钛得到过氧化钛水合物；利用阳离子交换树脂除去杂质NH4^＋；得到的溶液于100℃下密闭加热5h得到最终产物。XRD和FTIR结果表明，可以通过此法在低温下合成稳定的锐钛矿型TiO2溶胶水溶液，而且在制备过程中不会引入任何杂质。TiO2溶胶水溶液的光催化活性通过光催化降解丙酮来表征，结果表明其光催化表观反应速率常数相对P25大0．9×10^-3min^-1。

CTMP过氧化氢漂白技术的研究

吉林纸业股份有限公司生产特制A级胶印新闻纸的主要配浆——桦木CTMP,在没有解决CTMP洗涤设备之前,采用螯合剂预处理及无硅酸钠CTMP过氧化氢漂白工艺。目前,CTMP车间改进工艺,漂后已新装配了洗涤设备。在此基础上,吉林纸业股份有限公司科研所针对CTMP过氧化氢漂白技术进行了研究,目的是使用螯合剂DTPA—D—40及Na_2SiO_3两种药液,以降低漂白成本。

Catalytic removal of volatile organic compounds using ordered porous transition metal oxide and supported noble metal catalysts

Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalysts. Many catalysts including transition metal oxides, mixed metal oxides, and sup‐ported noble metals have been developed. Among these catalysts, the porous ones attract much attention. In this review, we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides, perovskites, and supported noble metal catalysts and their catalytic oxidation of VOCs. The porous catalysts outperformed their bulk counterparts. This excel‐lent catalytic performance was due to their high surface areas, high concentration of adsorbed oxy‐gen species, low temperature reducibility, strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures. Catalytic oxidation of carbon monoxide over typical catalysts was also discussed. We made conclusive remarks and pro‐posed future work for the removal of VOCs.

Experimental investigation of crystallization process of nanofluid by DSC

A water-TiO2nanofluid with a weight fraction of 5% and an average particle size of 75 nm is used to investigate the effect of TiO2 nanoparticles on the crystallization and melting behaviors of deionized water by using differential scanning calorimetry（DSC）at four different cooling rates,3,5,7,9 ℃/min.The DSC experimental results show that the water-TiO2 nanofluid has a lower supercooling degree and a faster crystallization rate than the deionized water.With the increase in the cooling rate,the influence of the TiO2 nanoparticles on the supercooling degree of the deionized water becomes greater,but on the crystallization rate it turns lower.During the melting process,compared with the deionized water,the water-TiO2 nanofluid has a lower melting temperature,a less latent heat and a higher melting rate.

Simultaneous hydrogen and peroxide production by photocatalytic water splitting

Photocatalytic oxidation of water is a promising method to realize large-scale H2O2 production without a hazardous and energy-intensive process. In this study, we introduce a Pt/TiO2(anatase) photocatalyst to construct a simple and environmentally friendly system to achieve simultaneous H2 and H2O2 production. Both H2 and H2O2 are high-value chemicals, and their separation is automatic. Even without the assistance of a sacrificial agent, the system can reach an efficiency of 7410 and 5096 μmol g^-1 h^–1 (first 1 h) for H2 and H2O2, respectively, which is much higher than that of a commercial Pt/TiO2(anatase) system that has a similar morphology. This exceptional activity is attributed to the more favorable two-electron oxidation of water to H2O2, compared with the four-electron oxidation of water to O2.

Kinetic Spectrophotometric Determination of Trace Titanium(Ⅳ) Based on Oxidation Discoloration of Acid Chrome Blue K with Hydrogen Peroxide

A simple and sensitive kinetic spectrophotometric method for the determination of trace amounts of titanium(IV),based upon the catalytic effect of Ti(IV) on the oxidation of acid chrome blue K (ACBK) by hydrogen peroxide in 0.002 mol/L sulfuric acid,is described. The reaction rate is monitored spectrophotometrically by measuring the decrease in absorbance of ACBK at 524 nm. The detection limit of the method is 1.01×10?9 g/mL,and the linear range is 0-0.048 mg/L. The influence of acidity,concentration of reactants,reaction time,reaction temperature and for-eign ions is also discussed. The optimum reaction conditions were established and some kinetic parameters determined. The apparent activation energy of the catalytic reaction is 5.32 kJ/mol. The relative standard deviation for the determi-nation of titanium(IV) at the concentration of 0.048 mg/L is calculated to be 1.31% (n = 11). In combination with sol-vent extraction separation,the method has been successfully applied to the determination of trace titanium(IV) in human hair,plant matter,tea and rock samples. The results are in good agreement with the certified values with the relative standard deviations (RSD) of 1.4%-3.5%.

Building surface defects by doping with transition metal on ultrafine TiO_2 to enhance the photocatalytic H_2 production activity

Inefficient charge separation and limited light absorption are two critical issues associated with high‐efficiency photocatalytic H2production using TiO2.Surface defects within a certain concentration range in photocatalyst materials are beneficial for photocatalytic activity.In this study,surface defects(oxygen vacancies and metal cation replacement defects)were induced with a facile and effective approach by surface doping with low‐cost transition metals(Co,Ni,Cu,and Mn)on ultrafine TiO2.The obtained surface‐defective TiO2exhibited a3–4‐fold improved activity compared to that of the original ultrafine TiO2.In addition,a H2production rate of3.4μmol/h was obtained using visible light(λ>420nm)irradiation.The apparent quantum yield(AQY)at365nm reached36.9%over TiO2‐Cu,significantly more than the commercial P25TiO2.The enhancement of photocatalytic H2production activity can be attributed to improved rapid charge separation efficiency andexpanded light absorption window.This hydrothermal treatment with transition metal was proven to be a very facile and effective method for obtaining surface defects.

Identifying the active sites in C-N codoped TiO_(2) electrode for electrocatalytic water oxidation to produce H_(2)O_(2)

Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material.For the two-electron water oxidation to produce H_(2)O_(2),competitive reactions,including four-and one-electron water oxidation and surface reconstruction derived from the high-oxidative environment co-existed,leading to great challenges to identify the real active sites on the electrode.In this work,Ti/TiO_(2)-based electrodes calcined under air,nitrogen,or urea atmospheres were selected as electrocatalysts for two-electron water oxidation.Electrochemical analyses were applied to evaluate the catalytic activity and selectivity.The morphological and current change on the electrode surface were determined by scanning electrochemical microscopy,while the chemical and valence evolutions with depth distributions were tested by XPS combined with cluster argon ion sputtering.The results demonstrated that Ti/TiO_(2) nanotube arrays served as the support,while the functional groups of carbonyl groups and pyrrolic nitrogen derived from the co-pyrolysis with urea were the active sites for the H_(2)O_(2) production.This finding provided a new horizon to design efficient catalysts for H_(2)O_(2) production.

Study on Crystallization of Titanium Silicalite Zeolite (Ⅱ)

In order to investigate the rules on formation of zeolite during crystallization of titanium silicalite zeolite (TS-1) the X-ray diffractometry and Foulier transform infra-red spectrometry were applied to track the process of crystallization of titanium silicalite zeolite. The research results revealed that at the initial stage of crystallization the interactions between silica gel and titania gel in the polymer blend could gradually lead to the formation of tiny crystal nuclei with complicated structure that could slowly grow up to form molecular sieves. Quite different from the conventional zeolites that use the acid sites as the catalytically active centers, the oxidative reactivity of the titanium silicalite zeolite was not proportional to its crystallinity and is associated with the oxidative centers of titanium contained in the zeolite.

TiO_2-doped Fe_3O_4 nanoparticles as high-performance Fenton-like catalyst for dye decoloration

Fenton reaction based on Fe2+-H2O2 system has been widely applied in water remediation, but the obvious drawbacks largely hinder its practical uses. Alternatively, heterogeneous nanomaterials with proper surface modification could be used as Fenton-like catalysts. Surface doping of Ti O2 could concentrate the pollutants surrounding the Fe3O4 catalyst, which might benefit the catalytic performance of Fe3O4. Herein, we reported that Ti O2-doped Fe3O4 nanoparticles(NPs) could be used as high-performance Fenton-like catalyst for dye decoloration in near neutral environment, where the doping of Ti O2 on Fe3O4 surface dramatically improved the catalytic activity of Fe3O4 in Fenton-like reaction. Ti O2-doped Fe3O4 NPs catalyzed the decomposition of H2O2 to oxidize methylene blue without external energy supply, resulting in effective decoloration. Ti O2-doped Fe3O4 NPs showed high catalytic activity under various p H values and even in the presence of radical scavenger. More catalysts and H2O2 would facilitate the decoloration. At higher temperature, the decoloration became faster and more effective. The implication to the environmental applications of Ti O2-doped Fe3O4 NPs is discussed.