CO2催化转化为高附加值燃料：现状、挑战及其未来方向

The electrochemical reduction of CO2 into liquid fuels especially coupling with the intermittent renewable electricity offers a promising means of storing electricity in chemical form, which reduc‐es the dependence on fossil fuels and mitigates the negative impact of anthropogenic CO2 emissions on the planet. Although converting CO2 to fuels is not in itself a new concept, the field has not sub‐stantially advanced in the last 30 years primarily because of the challenge of discovery of structural electrocatalysts and the development of membrane architectures for efficient collection of reactants and separation of products. This overview summarizes recent advances in catalytic conversion of CO2 and presents the challenges and future directions in producing value‐added fuels.     

1,2-亚苯基二硫桥[FeFe]-氢化酶模拟物选择性光催化还原CO2至CO

利用基于非贵金属的分子催化剂通过光驱动催化CO2还原生成CO是将太阳能储存为化学能和缓解CO2温室效应的有效途径之一,具有重要的科学意义和潜在的应用前景.已报道的非贵金属分子催化剂,大多数对于光驱动CO2还原表现出缓慢的催化反应速率和/或对CO产物的低选择性,反应常常伴随着质子还原产氢反应,只有很少几种非贵金属分子催化剂对光催化CO2还原生成CO表现出高催化反应速率(>100 h?1)和高选择性.研究表明,双核过渡金属配合物由于分子中邻近的两个金属中心的协同催化作用,对于CO2还原生成CO的催化活性明显高于相应的单核配合物.因此,具有两个邻近的金属离子的非贵金属双核配合物有望作为CO2选择性还原的高效分子催化剂.我们最近的研究发现,具有刚性、共轭亚苯基二硫桥结构的[FeFe]-氢化酶模拟物[(μ-bdt)Fe2(CO)6](1,bdt=苯-1,2-二巯基)能够高活性、高选择性地光化学还原CO2至CO,而与其类似的模拟物[(μ-edt)Fe2(CO)6](2,edt=乙烷-1,2-巯基)则不具有光催化还原CO2活性,表明铁铁氢化酶模拟物中硫-硫桥的结构是影响模拟物的催化性能的重要结构因素之一.可见光照射1/[Ru(bpy)3]2+/BIH(BIH=1,3-二甲基-2-苯基-2,3-二氢-1H-苯并[d]-咪唑)体系4.5 h,1催化生成CO的循环数(TON)为710,在初始1 h的转化率(TOF)为7.12 min^-1,CO的选择性达到97%,内量子效率为2.8%.有趣的是,向体系中加入TEOA时可以调节1的催化选择性,光化学反应能够在CO2还原产生CO和质子还原产生H2之间进行切换.此外,采用稳态荧光和瞬态吸收光谱研究了光催化体系中的电子转移,提出可能的光催化反应机理.该研究结果揭示了刚性硫-硫桥结构的氢化酶模拟物对光化学CO2还原至CO的特殊催化活性,拓展了铁铁氢化酶模拟物的催化多功能性.     

Fabrication of S-scheme hollow TiO2@Bi2MoO6 composite for efficiently photocatalytic CO2 reduction

Herein, an S-scheme hollow TiO₂@Bi₂MoO₆ heterojunction was synthesized for photocatalytic reduction of CO₂ under simulated sunlight. Among all prepared composites, the TiO₂@Bi₂MoO₆ with 20% of TiO₂ exhibited the highest CO yield (183.97 μmol/g within 6 h), which was 4.0 and 2.4 times higher than pristine TiO₂ and Bi₂MoO₆, respectively. The improved photocatalytic activity may be due to the formation of S-scheme heterojunction to promote the separation and transfer of photogenerated charge carriers. Additionally, this hollow structure provided abundant sites in terms of CO₂ adsorption and activation. Meanwhile, the photogenerated charge transfer mechanism of the S-scheme was verified by work function calculations, Electron paramagnetic resonance (EPR) measurements as well as X-ray photoelectron spectroscopy (XPS). This research presents a novel approach to improve photocatalytic reduction of CO₂ via morphology modulation and the fabrication of S-scheme heterojunction.     

光催化CO2还原的超薄层状催化剂

The acceleration of industrialization and the continuous upgradation of consumption structure has increased the atmospheric content of CO₂ far beyond the past levels, leading to a serious global environmental problem. Photocatalytic reduction of CO₂ is one of the most promising methods to solve the problem of rising atmospheric CO₂ content. The core of this technology is to develop efficient, environment-friendly, and affordable photocatalysts. A photocatalyst is a semiconductor that can absorb photons from sunlight and produce electron-hole pairs to initiate a redox reaction. Owing to their low specific surface areas, significant electron-hole recombination, and less surface-active sites, bulk photocatalysts are not satisfactory. Ultrathin layered materials have shown great potential for photocatalytic CO₂ reduction owing to their characteristics of large specific surface area, a large number of low-coordination surface atoms, short transfer distance from the inside to the catalyst surface, along with other advantages. Photoexcited electrons only need to cover a short distance to transfer to the nanowafer surface, and the speed of migrating electrons on the nanowafer surface is much higher than that in the layers or in the bulk catalyst. The ultrathin structure leads to significant coordinative unsaturation and even vacancy defects in the lattice structure of the atoms; while the former can be used as active sites for CO₂ adsorption and reaction, the latter can improve the separation of the electron-hole pair. This review summarizes the latest developments in ultrathin layered photocatalysts for CO₂ reduction. First, the photocatalytic reduction mechanism of CO₂ is introduced briefly, and the factors governing product selectivity are explained. Second, the existing catalysts, such as g-C₃N₄, black phosphorus (BP), graphene oxide (GO), metal oxide, transition metal dichalcogenides (TMDCs), perovskite, BiOX (X = Cl, Br, I), layered double hydroxide (LDH), 2D-MOF, MXene, and two-dimensional honeycomb-like Ge―Si alloy compounds (gersiloxenes), are classified. In addition, the prevalent preparation methods are summarized, including mechanical stripping, gas stripping, liquid stripping, chemical etching, chemical vapor deposition (CVD), template method, self-assembly of surfactant, and the intermediate precursor method of lamellar Bi-oleate complex. Finally, we introduced the strategy of improving photocatalyst performance on the premise of maintaining its layered structure, including the factors of thickness adjustment, doping, structural defects, composite, etc. The future opportunities and challenges of ultrathin layered photocatalysts for the reduction of carbon dioxide have also been proposed.     

2D covalent organic framework: a photoactive heterogeneous catalyst for chemical fixation of CO2 over propargyl amines in water under sunlight

We have demonstrated the efficient synthesis of Pd(II)-based 2D mesoporous covalent organic framework (COF) along with a small amount of Pd(0), which is characterized by different characterization tools. These studies suggest that this material with low bandgap energy (Eg) of 1.73 eV can exhibit great photocatalytic activity toward CO₂ fixation reaction. Therefore, we have applied the Pd(II)-loaded COF as a new and effective photocatalyst for the preparation of oxazolidinone through the chemical fixation of CO₂. The reaction takes place in green solvent (H₂O) in absence of any base and under the sunlight at atmospheric pressure of CO₂ without using any cocatalyst. The reaction does not happen in the dark. In this context, we showed that a turnover number (TON) of 3.392 × 10³ can be achieved using the catalytic cycle under sunlight. The light dependency of the reaction is also checked by a control experiment via light modulation between light on and off. Furthermore, the catalyst shows efficient reusability for multiple reaction cycles, and also the heterogeneity test of the material suggests minimal active metal leaching during the catalysis reaction cycles. These results for the photocatalytic synthesis of oxazolidinone by CO₂ incorporation over COF under sunlight open a new environment-friendly green pathway for the formation of oxazolidinones.     

Cu/MoO3-TiO2/SiO2上光催化CO2和C3H8合成异丁烯醛的研究

采用表面改性法和等体积浸渍法制备了金属修饰的负载型复合半导体材料Cu/MoO3-TiO2/SiO2, 用X射线衍射、 比表面积测定、 红外光谱、 拉曼光谱和紫外-可见漫反射等技术对固体材料的结构、 吸光性能和化学吸附性能进行了表征, 研究了该材料对CO2和丙烷合成异丁烯醛的光促表面催化规律. 结果表明, 半导体活性组分MoO3和TiO2在所制备的催化剂Cu/MoO3-TiO2/SiO2表面形成化学键, 并存在多种活性吸附位; 金属Cu的修饰拓展了固体材料对光源的响应范围, 提高了反应体系的吸光能力; 固体材料对CO2和丙烷的有效吸附使其在较低温度下就能促进异丁烯醛的紫外光化学合成, 反应选择性达到85％左右. 根据实验结果对光促CO2和丙烷表面催化合成异丁烯醛的机理进行了讨论.     

高选择性和稳定性SnO2纳米催化剂上 CO2电化学还原为甲酸

作为最重要的还原产品,甲酸是 CO2还原中非常有价值的液体燃料.已有研究报道, Sn类金属电极对甲酸生成有很好的催化活性,所用电解液均为 KHCO3溶液(0.5 mol/L),但多数研究没有对其电解液条件的影响给出清晰解释.一般而言,电解液 pH值会影响 H2O和 CO2还原的电极电势,酸性环境有利于氢析出,碱性环境则不利于甲酸形成.在中性偏碱性环境, CO2电解可以提供维持氧化物稳定性的可能性.同时,电解质浓度也极大地影响甲酸形成.研究表明,当在固定床反应器中使用 Sn颗粒电极,在 KHCO3溶液(0.5 mol/L)中甲酸的法拉第效率比 K2CO3溶液(0.1 mol/L)的法拉第效率更大.我们研究组通过简单的水热自组装法成功制备了一种纳米结构 SnO2催化剂.其中 SnO2-50纳米催化剂由三维多级结构组成,为纳米颗粒和微米球的聚集体,其中含有直径为500 nm?1μm的高度多孔结构.该催化剂负载气体扩散电极用于 CO2电化学还原,表现出优异的 CO2还原催化活性和甲酸选择性.与其他文献报道相比,该电极具有明显的低过电位(?0.56 V vs. SHE).经研究发现,这与甲酸形成由传质和电荷传递过程控制有关,同时 CO2还原强烈依赖于电解液条件.此外,催化剂的电化学性能和甲酸选择性强烈依赖于电解液浓度.在0.5 mol/L KHCO3电解液中,当电解液浓度为0.1?0.5 mol/L时,催化性能随电解液浓度增加而提高,同时在电解液浓度为0.5 mol/L时催化性能达到最佳,获得56%的甲酸法拉第效率,这主要是由于 HCO3?直接参与反应的结果.在电解液浓度较低时,甲酸的形成由传质控制,而在电解液浓度较高时,甲酸的形成则由电荷传递控制.
　　同时我们发现在形成甲酸过程中,电解液 pH值对 CO2电化学还原过程有很大影响.为了研究电解液pH值影响,重点考察了pH值分别为6,7,8.3和9时的电位值,其原因是酸性过高有利于氢气形成,碱度过高不利于甲酸形成.结果表明,pH =8.3的电解液为 CO2还原的最佳电解液条件.此外,在最负的电势下,电解液pH=8.3时,阴极电流密度比其他电解液都大,几乎是pH=6的电解液的2倍.此时在中性偏碱性环境下, CO2还原可以提供维持氧化物稳定性的可能性.当电解液 pH增加到9.0时,甲酸产量及法拉第效率略有下降,可能是碱性环境不利于甲酸形成.
　　同时,对 SnO2-50纳米催化剂经28 h电解后的甲酸法拉第效率的衰减机制进行了深入研究.结果表明,随着电解时间延长,甲酸法拉第效率衰减.电解时间为1?28 h时,法拉第效率和甲酸产量均保持平稳下降趋势,28 h后法拉第效率由初始的56%降至24%.有文献报道,甲酸法拉第效率随电解时间的改变主要是由于阳极上甲酸的氧化或阴极上杂质的污染.为了证明阴极电解后的状态,我们对 SnO2-50/GDL阴极电解前后的 XPS谱进行了分析.结果发现,法拉第效率的下降是由于痕量氟离子沉积到 SnO2-50/GDL电极表面,这些痕量氟离子可能来自反应槽,阻碍电极表面 CO2电化学还原为甲酸.     

Recent advances in photo-enhanced dry reforming of methane: A review

Converting methane and carbon dioxide into hydrogen and carbon monoxide is significant and attractive because it can mitigate the greenhouse effect and produce useful chemical intermediate. However, these two greenhouse gases are challenging to convert due to their high bond energy and chemically inert. Although thermocatalytic dry reforming of methane (DRM) achieves high efficiency, it requires high energy and often causes deactivation due to carbon deposition. Recently, a lot of research results show that photo-enhanced DRM is a promising and green route for this reaction under relatively mild conditions. This review first introduces the importance and challenge of CH₄ and CO₂ conversion. Then, we summarize the related reports of photo-enhanced dry reforming of methane in detail, including material preparation, experimental conditions and results, and mechanism study. In particular, the related studies have been classified according to types of input energy and the types of catalyst. Finally, we provide insightful perspectives and prospects for the future development of this field.     

Effect of Micropores of a Porous Coordination Polymer on the Product Selectivity in RuII Complex-catalyzed CO2 Reduction

To develop an efficient CO2 reduction catalyst, hybridizing a molecular catalyst and a porous coordination polymer (PCP) is a promising strategy because it can combine both advantages of the precise reactivity control of the former and the CO2 adsorption property of the latter. Although several PCP hybrid catalysts have been reported to date, the CO2 sorption behavior and the CO2 reduction reactivity have been investigated separately, and the CO2 enrichment during the catalysis is still unclear. We report CO2 photoreduction under different temperatures and pressures using a PCP-RuII complex hybrid catalyst. The product selectivity (CO or HCOOH) varied depending on the reaction conditions. The altered selectivity could be interpreted in terms of the CO2 capture in the micropores of a PCP.     

氧化物钙钛矿的光催化研究进展：CO2还原、水裂解、固氮

At present, more than 80% of the world's energy demand is fulfilled by the burning of fossil fuels, which has caused the production of a large amount of greenhouse gases, leading to global warming and damage to the environment. The high consumption of fossil fuels every year causes the energy crisis to become increasingly serious. Finding a sustainable and pollution-free energy source is therefore essential. Among all forms of energy sources, solar energy is preferred because of its cleanliness and inexhaustible availability. The energy provided by one year of sunlight is more than 100 times the total energy in known fossil fuel reserves worldwide; however, the extent of solar energy currently used by mankind each year is minute; thus developments in solar energy are imperative. To address the urgent need for a renewable energy supply and to solve environmental problems, a variety of technologies in the field of photocatalysis have been developed. Photocatalytic technology has attracted significant attention because of its superior ability to convert clean solar energy into chemical fuels. Among the photocatalytic materials emerging in an endless stream, perovskite oxide, with the general formula of ABO₃, has great potential in the fields of solar cells and photocatalysis as each site can be replaced by a variety of cations. Furthermore, owing to its unique properties such as high activity, robust stability, and facile structure adjustment, perovskite oxide photocatalysts have been widely used in water decomposition, carbon dioxide reduction and conversion, and nitrogen fixation. In terms of carbon dioxide reduction, oxide perovskites can achieve precise band gap and band edge tuning owing to its long charge diffusion length and flexibility in composition. For the development and utilization of solar energy in the environmental field, perovskite oxide and its derivatives (layered perovskite oxide) are used as photocatalysts for water decomposition and environmental remediation. In terms of nitrogen fixation, the conventional Haber-Bosh process for ammonia synthesis, which has been widely used in the past, requires high temperature and high energy. Therefore, we summarize the recent advances in perovskite oxide photocatalysts for nitrogen fixation from the aspect of activating the adsorbed N₂ by weakening the N $ \equiv $N triple bond, promoting charge separation, and accelerating the charge transfer to the active sites to realize the photochemical reaction. Overall, this review article presents the structure and synthesis of perovskite oxide photocatalysis, focusing on the application of photocatalysis in water splitting, carbon dioxide reduction, and nitrogen fixation. This review concludes by presenting the current challenges and future prospects of perovskite oxide photocatalysts.      

Synthesis of immobilized TiO2 nanowires by anodic oxidation and their gas phase photocatalytic properties

In this paper, anodic oxidation method was successfully employed to the direct growth of immobilized TiO₂ nanowires on titanium foil in ethylene glycol electrolyte solution contained HF and water. The morphologies of the TiO₂ nanowires could be tuned by changing the content of HF and water. The structures, morphologies and optical properties of TiO₂ nanowires were characterized by SEM, XRD, UV–vis and PL. It was found that the nanowires originally grew from the splitting of TiO₂ nanotubes. The gas phase photocatalytic activities were investigated by photodegradation of gaseous toluene under UV irradiation, and irregular TiO₂ nanowires showed the best photocatalytic ability.     

利用光热耦合下的光电导研究TiO2光热催化还原CO2（英文）

利用太阳能缓解能源危机和解决环境污染,是当前和未来的全球性课题.其中,光催化技术的研究步伐日渐加快.这不仅体现在光催化材料种类的增加,更体现在以光催化为基础的多场协同催化,特别是光热耦合作用成为增强光催化性能的一种高效、可靠的方法.氧空位的引入不仅可以拓宽催化剂对可见光的吸收、抑制载流子的复合、促进反应物的吸附以及降低反应的活化能,而且对于光热协同催化效率的提升有着重要的贡献.然而,目前光热协同催化的表征多局限于常规的光催化手段.开展光热耦合下的测量技术对深刻理解光热催化是十分必要的.本文研究温度、气氛、氧空位浓度对TiO2光电导的影响,构建光电导与光热催化活性之间的关系.我们将商用的ST-01 TiO2制成浆料,利用丝网印刷法将浆料覆盖在刻有沟槽的FTO上,并通过N2/H2混合气不同温度退火,得到不同氧空位含量的TiO2薄膜(Ov-TiO2).采用紫外-可见光谱(UV-Vis),拉曼光谱(Raman),电子顺磁共振(ESR)等手段对样品进行了表征.结果表明,N2/H2退火温度越高,氧空位浓度越高.我们对不同浓度氧空位的样品进行了光催化及光热协同催化CO2还原实验.结果表明,适量氧空位的样品(H2-150)光催化还原CO2性能最差,但光热协同催化还原CO2的性能最佳.我们对其光电导值的衰减情况进行了分析,看到H2-150样品在CO2气氛、光热条件下,电导衰减加快.由于光电导的衰减是由电荷复合和电荷参与的表面反应共同决定的,为确定是哪一因素决定了电导的衰减,我们进一步测试了H2-150样品在N2气氛下的电导衰减情况.结果发现,H2-150样品在N2气氛、光热条件下电导衰减反而变慢.这表明,造成H2-150样品在CO2气氛、光热条件下的电导衰减加快是光热条件下CO2还原速率加快,也验证了H2-150具有较好的光热催化CO2活性.与H2-150样品不同的是,大量氧空位样品(H2-350)在CO2气氛、光热条件下电导衰减反而变慢,我们认为这是由于H2-350存在深能级缺陷,在热的作用下会将捕获的电子释放,因此延缓了光电导的衰减.但由于深能级电子的还原能力较弱,所以H2-350样品的光热CO2还原活性稍逊于H2-150.综上所述,在光热电导与光热催化相关的研究中,我们证实了在Ov-TiO2中被捕获的电子在热激发下可再次向导带弛豫,从而解释了Ov-TiO2优异的光热催化性能.因此,光热电导的研究在理解光热催化方面具有重要的前景.     

Cloride-derived copper electrode for efficient electrochemical reduction of CO2 to ethylene

Transformation of CuCl into cubic structure of bi-phasic Cu₂O-Cu (CB-Cu) enhanced production of ethylene from electrochemical reduction of CO₂.     

Organic molecules involved in Cu-based electrocatalysts for selective CO2 reduction to C2+ products

Electrocatalytic carbon dioxide (CO₂) reduction reaction (CO₂RR) is a promising process to mitigate the environmental issues caused by CO₂, as well as to produce valuable multicarbon (C₂₊) products. Significant progresses have been made to explore highly efficient Cu-based electrocatalysts for CO₂RR in recent years. Adding organic molecules into electrocatalytic systems can tune the CO₂ interaction with the electrocatalysts for CO₂RR, therefore, the final C₂₊ products, which are not solely achieved by inorganic modification. In this review, we will summarize the recent progress of the organic molecules participation in CO₂ electroreduction to C₂₊ products on Cu-based electrocatalysts. The applied organic molecules are reviewed based on the heteroatoms (N and S), with the emphasis on their roles in activity and selectivity toward C₂₊ products. A perspective on the application of organic molecules for efficient and selective CO₂RR has been provided.     

Catalysts in electro-, photo- and photoelectrocatalytic CO2 reduction reactions

Carbon dioxide (CO₂) is regarded as a main contributor to the greenhouse effect. As a potential strategy to mitigate its negative impacts, the reduction of CO₂ is environmentally critical, economically meaningful and scientifically challenging. Being both thermodynamically and kinetically unfavored, CO₂ reduction requires catalysts as a crucial component irrespective of the reaction modes, be it electrocatalytic, photoelectrocatalytic or photocatalytic. In an effort to systematically review the types of catalysts that have been studied for CO₂ reduction, we categorize them into two major groups: those being activated by external sources and those being photoexcited and activated themselves. Attention is focused on the detailed mechanisms for each group by which the reduction of CO₂ proceeds, yielding a summary of the guiding principles for catalyst designs. This review highlights the importance of mechanistic studies, which permits us to discuss our perspectives on potential directions of catalyst investigation for future catalytic CO₂ reduction research.     

Preparation of High-Orderly TiO2 Nanotubes in Organic Solution and Characterization of C-doped TiO2

"High-orderly TiO2 nanotube arrays were fabricated by anodic oxidation of pure titanium substrate in organic electrolyte containing fluoride. Different morphological nanotubes of titania were obtained through controlling the different anodization voltages and durations. The length of the longest nanotubes was approximately 60 1m and the length-to-width aspect ratio was about 600. The nanotube layers were then annealed at different temperatures (450, 550, and 650 oC) in air for 2 h. The samples were characterized by scanning electron microscopy, X-ray diffraction (XRD), energy dispersive X-Ray (EDS) and UV-Vis spectrometer. The XRD results demonstrated that the as-anodized samples were amorphous and the structure changed to antanse and rutile when the samples were annealed at higher temperature. The EDS microanalysis indicated the presence of carbon in the TiO2 nanotubes. The result of degradation of methylene blue showed clearly that the photocatalytic activity of C-doped TiO2 nanotubes increased by 10%."     

气相金属催化反应综述

金属催化剂在工业、环境、能源以及生物等过程具有重要的应用.设计具有特定活性、环境友好型以及室温下具有反应活性的催化剂,需要在分子水平对金属催化剂的基元步骤,活性位点的结构以及催化反应微观机理有充分的认识.然而,由于宏观催化剂表面结构异常复杂,催化反应常受到溶剂、压力、金属颗粒团聚、催化剂表面缺陷等因素的干扰,利用现有实验仪器,从微观角度探索金属催化反应机理仍具有较大挑战,因此,对金属催化剂活性位的结构以及反应微观机理的认识还不十分清楚.质谱方法结合现代量子化学理论计算,提供了在气相条件下实验探索化学反应微观机理的有力工具,团簇反应可在隔离外界条件、可控以及可重复条件下进行,可以排除一些难以控制因素的干扰,可在化学键和分子结构水平认识金属活性位的结构以及催化反应的微观机理.气相金属团簇离子可用多种实验方法制备,与反应物分子反应后可利用多种质谱仪器探测,根据实验上所得的具有反应活性的团簇,结合现代量子化学理论模拟,得到金属催化反应的基元步骤以及微观反应机理信息,所得反应机理信息为宏观催化剂的设计提供重要理论研究基础.本综述总结了团簇实验上已经探测到的金属单原子离子、金属团簇、金属氧化物团簇和金属化合物催化的气相反应.反应物分子囊括了大量的无机和有机分子,包括CO,H2,CH4,C2H2,C2H4,C6H6,CH3OH,HCOOH,CH3COOH等.本综述主要介绍了以下三类催化反应:(1)CO催化氧化;(2)CH4催化转化;(3)催化脱羧反应,并重点关注贵金属单原子掺杂团簇独特的催化反应性.单原子催化剂可最大限度地利用有限的贵金属.在化学反应方面,单原子催化剂具有特异的反应活性,选择性以及稳定性.本综述对气相团簇反应中报道的两个重要的贵金属单原子掺杂团簇的催化反应进行了详细介绍:(1)金原子掺杂的AuAl3O3-5+团簇为首次报道的可以利用分子氧催化氧化CO的团簇单原子催化剂,我们对Au原子起催化作用的本质原因进行了介绍:(2)铂原子掺杂的PtAl3O5-7-团簇能利用分子氧催化氧化CO,该研究提出了"电负性阶梯"效应来解释Pt原子催化的微观机理,且此效应有望对大部分贵金属适用.此外,本综述对CO催化氧化反应和CH4催化转化反应的研究现状以及尚未解决的问题进行了剖析.相比CO的催化氧化反应,科学家对CH4催化转化反应机理的认识还不够深入,还需要进一步实验研究,而团簇单原子催化剂有望在此领域有所突破.     

Pt nanocrystallines/TiO2 with thickness-controlled carbon layers: Preparation and activities in CO oxidation

Pt nanocrystallines (~3 nm) covered with controllable carbon layers were synthesized by photochemical reduction method which exhibited extraordinary anti-sintering properties and different CO oxidation activities.     

TiO2 photocatalysis for the degradation of pollutants in gas phase: From morphological design to plasmonic enhancement

TiO₂-based photocatalysis has become a viable technology in various application fields such as (waste)water purification, photovoltaics/artificial photosynthesis, environmentally friendly organic synthesis and remediation of air pollution. Because of the increasing impact of bad air quality worldwide, this review focuses on the use and optimization of TiO₂-based photocatalysts for gas phase applications. Over the past years various specific aspects of TiO₂ photocatalysis have been reviewed individually. The intent of this review is to offer a broad tutorial on (recent) trends in TiO₂ photocatalyst modification for the intensification of photocatalytic air treatment. After briefly introducing the fundamentals of photocatalysis, TiO₂ photocatalyst modification is discussed both on a morphological and an electronic level from the perspective of gas phase applications. The main focus is laid on recent developments, but also possible opportunities to the field. This review is intended as a solid introduction for researchers new to the field, as well as a summarizing update for established investigators.     

Photocatalytic decolouration,degradation and disinfection capability of Ag2CO3/ZnO in natural sunlight

In this study, a series of hybrid Ag₂CO₃/ZnO composites were synthesised via a simple precipitation route and investigated for discolouration-degradation of Methylene Blue and disinfection of Escherichia coli in natural sunlight. It was observed that the photonic efficiency of discolouration was more than 6 times that of the conventionally popular TiO₂, under experimental conditions; 100% Total Organic Carbon reduction was observed in 30 ?min and 32% disinfection in an hour. This upswing in the performance is attributed to favourable modulation of the dynamics of charge transfer. The photocatalysts were characterized by X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, Brunauer, Emmett and Teller and Ultraviolet–Visible-Near-InfraRed Spectroscopy. An equitable photocatalyst functional mechanism has also been proposed on the basis of Tauc plot and scavenging experiments. The effect of influencing parameters has also been investigated and reported in terms of photonic efficiency. Since the entire study is carried out in direct sunlight, it inherently supports realizable solar energy applications in wastewater treatment.