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“白色污染”已成为目前普遍关注的一个全球性环保课题。将光催化剂掺入到塑料中制备出环境友好的可光降解复合塑料,利用其光催化活性可以使废弃塑料在太阳光的照射下发生有效降解,是解决“白色污染”问题的有效途径之一。本文综述了近年来固相光催化降解废弃塑料的研究进展,介绍了光催化剂TiO2、ZnO、α-FeOOH和H3PW12O40对废弃塑料的固相光催化降解效率及各种复合塑料的光催化降解机理,阐述了对光催化剂进行表面改性可以改善其在聚合物中的分散性,以及对光催化剂进行修饰可以提高其对可见光的吸收,从而提高复合塑料的固相光催化降解活性及对太阳光的有效利用率。最后,展望了固相光催化技术在废弃塑料处理领域的应用前景。 相似文献
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Intercalation of Highly Dispersed Metal Nanoclusters into a Layered Metal Oxide for Photocatalytic Overall Water Splitting
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Takayoshi Oshima Dr. Daling Lu Prof. Dr. Osamu Ishitani Prof. Dr. Kazuhiko Maeda 《Angewandte Chemie (International ed. in English)》2015,54(9):2698-2702
Metal nanoclusters (involving metals such as platinum) with a diameter smaller than 1 nm were deposited on the interlayer nanospace of KCa2Nb3O10 using the electrostatic attraction between a cationic metal complex (e.g., [Pt(NH3)4]Cl2) and a negatively charged two‐dimensional Ca2Nb3O10? sheet, without the aid of any additional reagent. The material obtained possessed eight‐fold greater photocatalytic activity for water splitting into H2 and O2 under band‐gap irradiation than the previously reported analog using a RuO2 promoter. This study highlighted the superior functionality of Pt nanoclusters with diameters smaller than 1 nm for photocatalytic overall water splitting. This material shows the greatest efficiency among nanosheet‐based photocatalysts reported to date. 相似文献
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Dr. Nikolaos G. Moustakas Felix Lorenz Dr. Martin Dilla Dr. Tim Peppel Prof. Dr. Jennifer Strunk 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):17213-17219
Evidence is provided that in a gas-solid photocatalytic reaction the removal of photogenerated holes from a titania (TiO2) photocatalyst is always detrimental for photocatalytic CO2 reduction. The coupling of the reaction to a sacrificial oxidation reaction hinders or entirely prohibits the formation of CH4 as a reduction product. This agrees with earlier work in which the detrimental effect of oxygen-evolving cocatalysts was demonstrated. Photocatalytic alcohol oxidation or even overall water splitting proceeds in these reaction systems, but carbon-containing products from CO2 reduction are no longer observed. H2 addition is also detrimental, either because it scavenges holes or because it is not an efficient proton donor on TiO2. The results are discussed in light of previously suggested reaction mechanisms for photocatalytic CO2 reduction. The formation of CH4 from CO2 is likely not a linear sequence of reduction steps but includes oxidative elementary steps. Furthermore, new hypotheses on the origin of the required protons are suggested. 相似文献
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Qikai Shen Changyan Cao Runkun Huang Lei Zhu Xin Zhou Qinghua Zhang Lin Gu Weiguo Song 《Angewandte Chemie (International ed. in English)》2020,59(3):1216-1219
Direct conversion of methane to value‐added chemicals with high selectivity under mild conditions remains a great challenge in catalysis. Now, single chromium atoms supported on titanium dioxide nanoparticles are reported as an efficient heterogeneous catalyst for direct methane oxidation to C1 oxygenated products with H2O2 as oxidant under mild conditions. The highest yield for C1 oxygenated products can be reached as 57.9 mol molCr?1 with selectivity of around 93 % at 50 °C for 20 h, which is significantly higher than those of most reported catalysts. The superior catalytic performance can be attributed to the synergistic effect between single Cr atoms and TiO2 support. Combining catalytic kinetics, electron paramagnetic resonance, and control experiment results, the methane conversion mechanism was proposed as a methyl radical pathway to form CH3OH and CH3OOH first, and then the generated CH3OH is further oxidized to HOCH2OOH and HCOOH. 相似文献
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Chu-Xuan Liu Kesheng Liu Yanjun Xu Dr. Zhuan Wang Prof. Dr. Yuxiang Weng Dr. Fulai Liu Prof. Dr. Yong Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(16):e202401255
Polylactic acid (PLA) has attracted increasing interest as a sustainable plastic because it can be degraded into CO2 and H2O in nature. However, this process is sluggish, and even worse, it is a CO2-emitting and carbon resource waste process. Therefore, it is highly urgent to develop a novel strategy for recycling post-consumer PLA to achieve a circular plastic economy. Herein, we report a one-pot photoreforming route for the efficient and selective amination of PLA waste into value-added alanine using CoP/CdS catalysts under mild conditions. Results show the alanine production rate can reach up to 2.4 mmol gcat−1 h−1, with a high selectivity (>75 %) and excellent stability. Time-resolved transient absorption spectra (TAS) reveal that CoP can rapidly extract photogenerated electrons from CdS to accelerate proton reduction, favoring hole-dominated PLA oxidation to coproduce alanine. This study offers an appealing way for upcycling PLA waste and creates new opportunities for green synthesis of amino acids. 相似文献
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Improving the Photocatalytic Reduction of CO2 to CO through Immobilisation of a Molecular Re Catalyst on TiO2
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Dr. Christopher D. Windle Ernest Pastor Dr. Anna Reynal Dr. Adrian C. Whitwood Dr. Yana Vaynzof Prof. James R. Durrant Prof. Robin N. Perutz Dr. Erwin Reisner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(9):3746-3754
The photocatalytic activity of phosphonated Re complexes, [Re(2,2′‐bipyridine‐4,4′‐bisphosphonic acid) (CO)3(L)] (ReP; L=3‐picoline or bromide) immobilised on TiO2 nanoparticles is reported. The heterogenised Re catalyst on the semiconductor, ReP–TiO2 hybrid, displays an improvement in CO2 reduction photocatalysis. A high turnover number (TON) of 48 molCO molRe?1 is observed in DMF with the electron donor triethanolamine at λ>420 nm. ReP–TiO2 compares favourably to previously reported homogeneous systems and is the highest TON reported to date for a CO2‐reducing Re photocatalyst under visible light irradiation. Photocatalytic CO2 reduction is even observed with ReP–TiO2 at wavelengths of λ>495 nm. Infrared and X‐ray photoelectron spectroscopies confirm that an intact ReP catalyst is present on the TiO2 surface before and during catalysis. Transient absorption spectroscopy suggests that the high activity upon heterogenisation is due to an increase in the lifetime of the immobilised anionic Re intermediate (t50 %>1 s for ReP–TiO2 compared with t50 %=60 ms for ReP in solution) and immobilisation might also reduce the formation of inactive Re dimers. This study demonstrates that the activity of a homogeneous photocatalyst can be improved through immobilisation on a metal oxide surface by favourably modifying its photochemical kinetics. 相似文献
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Environmental Transmission Electron Microscopy Study of Diesel Carbon Soot Combustion under Simulated Catalytic‐Reaction Conditions
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Prof. Dr. Kohsuke Mori Keitaro Watanabe Dr. Takeshi Sato Prof. Dr. Hiromi Yamashita 《Chemphyschem》2015,16(7):1347-1351
Environmental transmission electron microscopy (ETEM) is used to monitor the catalytic combustion of diesel carbon soot upon exposure to molecular oxygen at elevated temperatures by using a gas‐injection specimen heating holder. The reaction conditions simulated in the ETEM experiments reconstruct real conditions effectively. This study demonstrated for the first time that soot combustion occurs at the soot–catalyst interface for both Ag/CeO2 and Cu/BaO/La2O3 catalysts. 相似文献
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模拟太阳光下稀土Gd掺杂TiO2纳米晶的光催化性能研究 总被引:1,自引:0,他引:1
以甲基橙的光催化降解为探针反应,采用氙灯模拟自然条件下的太阳光,评价了通过酸催化的溶胶-凝胶法制备的稀土Gd掺杂改性TiO2纳米晶的光催化活性及对甲基橙水溶液TOC的去除效果.运用XRD和UV-Vis DRS表征技术考察了Gd掺杂对纳米TiO2的微晶尺寸、晶体结构与光学性能的影响.结果表明,Gd掺杂可以抑制TiO2由锐钛矿相向金红石相的转变,阻碍TiO2晶粒增长,使TiO2的光吸收带边发生蓝移且有利于对可见光的吸收,从而使Gd掺杂TiO2在模拟太阳光下光催化降解甲基橙的能力得到明显提高,但样品对甲基橙水溶液TOC的去除效果要滞后于其对色度的去除. 相似文献
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Vincent Wing‐hei Lau Dr. Leon G. A. van de Water Prof. Anthony F. Masters Prof. Thomas Maschmeyer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(10):2923-2930
Synthetic solvent systems for the fine‐tuned preparation of CdS nanocrystallites, active in visible‐light photocatalytic hydrogen production, were studied. To control crystallite size and spectral properties, the CdS crystals were synthesised by using different solvent systems, containing a series of tetrabutylammonium amino carboxylate ionic liquids as the crystal‐growth control agents. Six samples of CdS, all with similar physical and spectral properties, exhibited greatly varying photocatalytic activity, with the most active sample outperforming the least active one by almost 60 %. To rationalise this effect, the intermolecular interactions of the synthesis solvent system with the growing CdS nanocrystallites were characterised by using the Reichart betaine dye and the ${E{{{\rm N}\hfill \atop {\rm T}\hfill}}}$ polarity scale. A correlation was observed between the ${E{{{\rm N}\hfill \atop {\rm T}\hfill}}}$ values of the solvent system and the photocatalytic activity of the CdS nanocrystallite, suggesting that the hydrogen‐bond‐donating ability and/or dipolarity/polarisability interactions of the solvent system led to the preferential formation of active surfaces/surface sites on the CdS crystals. 相似文献
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Central Doping of a Foreign Atom into the Silver Cluster for Catalytic Conversion of CO2 toward C−C Bond Formation
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Yuanyuan Liu Xiaoqi Chai Xiao Cai Dr. Mingyang Chen Prof. Rongchao Jin Prof. Weiping Ding Prof. Yan Zhu 《Angewandte Chemie (International ed. in English)》2018,57(31):9775-9779
Clusters with an exact number of atoms are of particular interest in catalysis. Their catalytic behaviors can be potentially altered with the addition or removal of a single atom. Now the effects of doping with a single foreign atom (Au, Pd, and Pt) into the core of an Ag cluster with 25 atoms on the catalytic properties are explored, where the foreign atom is protected by 24 Ag atoms (Au@Ag24, Pd@Ag24, and Pt@Ag24). The central doping of a single atom into the Ag25 cluster has a substantial influence on the catalytic performance in the carboxylation reaction of CO2 with terminal alkyne through C?C bond formation to produce propiolic acid. These studies reveal that the catalytic properties of the cluster catalysts can be dramatically changed with the subtle alteration by a single atom away from the active sites. 相似文献
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传统化石能源燃烧产生CO2引起的地球变暖和能源短缺已经成为一个严重的全球性问题.利用太阳光和光催化材料将CO2还原为碳氢燃料,不仅可以减少空气中CO2浓度,降低温室效应的影响,还可以提供碳氢燃料,缓解能源短缺问题,因此日益受到各国科学家的高度关注.本文综述了光催化还原CO2为碳氢燃料的研究进展,介绍了光催化还原CO2的反应机理,并对现阶段报道的光催化还原CO2材料体系进行了整理和分类,包括TiO2光催化材料,ABO3型钙钛矿光催化材料,尖晶石型光催化材料,掺杂型光催化材料,复合光催化材料,V、W、Ge、Ga基光催化材料及石墨烯基光催化材料.评述了各种材料体系的特点及光催化性能的一些影响因素.最后对光催化还原CO2的研究前景进行了展望. 相似文献
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Black TiO2 has emerged as one of the most promising photocatalysts recently discovered. The reason behind its catalytic activity is considered to be due to the presence of defects and Ti3+ species at the surface of black TiO2 nanostructures, which are crucial for its diverse applications. Moreover, disordered/crystalline surface layers and bulk regions have been identified and appear to influence the intrinsic properties of the material. Here, we present the latest studies on the use of black TiO2 for metal free hydrogen production, as well as for CO2 photoreduction and N2 photofixation. After highlighting the structure/property relations, we conclude with some critical questions and suggest further topics of research in order to better understand the underlying mechanisms of light absorption in black TiO2, especially towards solar fuels production. 相似文献
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Kenta Aihara Dr. Kosaku Kato Dr. Tomoki Uchiyama Dr. Shuhei Yasuda Prof. Toshiyuki Yokoi Prof. Akira Yamakata Prof. Yoshiharu Uchimoto Prof. Kazuhiko Maeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202200875
Pb2Ti2O5.4F1.2 modified with various metal cocatalysts was studied as a photocatalyst for visible-light H2 evolution. Although unmodified Pb2Ti2O5.4F1.2 showed negligible activity, modification of its surface with Rh led to the best observed promotional effect among the Pb2Ti2O5.4F1.2 samples modified with a single metal cocatalyst. The H2 evolution activity was further enhanced by coloading with Pd; the Rh−Pd/Pb2Ti2O5.4F1.2 photocatalyst showed 3.2 times greater activity than the previously reported Pt/Pb2Ti2O5.4F1.2. X-ray absorption fine-structure spectroscopy, photoelectrochemical, and transient absorption spectroscopy measurements indicated that the coloaded Rh and Pd species, which were partially alloyed on the Pb2Ti2O5.4F1.2 surface, improved the electron-capturing ability, thereby explaining the high activity of the coloaded Rh−Pd/Pb2Ti2O5.4F1.2 catalyst toward H2 evolution. 相似文献
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