CeO2 Particles Anchored to Ni2P Nanoplate for Efficient Photo-catalytic Hydrogen Evolution

Photocatalytic hydrogen evolution can convert intermittent and dispersive solar energy into hydrogen with high energy density,which is expected to fundamentally solve the problems of environmental pollution and energy shortages.In this experiment,the performance of the catalyst is modified by introducing cocatalyst and morphology control.Ni(OH)2 nanoflowers are used as substrates to derive nanoplate stack Ni₂P by high-temperature phosphating method,and a great many of CeO₂ nanoparticles are anchored in the Ni₂P.This unique 3D/0D combination effectively inhibits the agglomeration of CeO₂ nanoparticles and shortens the electron transfer path.Secondly,the introduction of metal-like performance of Ni₂P broadens the light absorption range of the catalyst and reduces the overpotential of the catalyst,which is a key factor in enhancing the catalytic activity.The design ideas of this experiment have reference significance for the design of efficient and environmentally friendly photocatalysts.     

Studies on the roles of vanadyl sulfate and sodium nitrite in catalytic oxidation of benzyl alcohol with molecular oxygen

An efficient catalytic system consisting of vanadyl sulfate/sodium nitrite was disclosed previously for the oxidation of benzylic alcohols into aldehydes with molecular oxygen.However,the roles of catalyst components were not investigated.In this paper,we examined catalytic oxidation of benzyl alcohol as a model reaction,especially by infrared spectroscopy.The role of each component is discussed including nitrite,vanadyl,sulphate,and water.Sodium nitrite could be converted into nitrate and nitric acid.The vanadium(IV)could be smoothly oxidized into vanadium(V)under mild and acidic conditions without any organic ligands.The transformation of sulfate and bisulfate,the cessation of an induction period,and the oxidation of benzyl alcohol were closely interrelated.The multiple roles of water are discussed,including reduction of the induction period,participation in redox cycles of nitric compounds,deactivation of vanadium,and as a byproduct of oxidation.This study contributes to further development of aerobic oxidation using vanadium based catalysts.     

Improving photoreduction of CO_2 with water to CH_4 in a novel concentrated solar reactor

CO_2 photoreduction is an attractive process which allows the storage of solar energy and synthesis of solar fuels. Many different photocatalytic systems have been developed, while the alternative photo-reactors are still insufficiently investigated. In this work, photoreduction of CO_2 with H_2O into CH_4 was investigated in a modified concentrating solar reactor, using TiO_2 and Pt/TiO_2 as the catalysts. The TiO_2 and Pt/TiO_2 samples were extensively characterized by different techniques including powder X-ray diffraction(XRD), N_2 adsorption/desorption and UV–vis absorption. The catalytic performance of the TiO_2 and Pt/TiO_2 samples in the gas phase was evaluated under unconcentrated and concentrated Xe-lamp light and nature solar light with different concentrating ratios. Various parameters of the reaction system and the catalysts were investigated and optimized to maximize the catalytic performance of CO_2 reduction system. Compared with the normal light irradiation, the TiO_2 and Pt/TiO_2 samples show higher photocatalytic activity(about 6–7 times) for reducing CO_2 into CH_4 under concentrated Xe-lamp light and nature solar light. In the range of experimental light intensity, it is found that the concentration of the light makes it suitable for the catalytic reaction, and increases the utilization efficiency of the TiO_2 and Pt/TiO_2 samples while does not decrease the quantum efficiency.     

Efficient oxidation of benzyl alcohol with heteropolytungstate as reaction-controlled phase-transfer catalyst

A series of heteropolytungstates has been synthesized and utilized as catalysts to catalyze oxidation of benzyl alcohol with aqueous hydrogen peroxide.The results indicated that three of these catalysts showed the properties of reaction-controlled phase- transfer catalysis,and they had excellent catalytic ability to the oxidation of benzyl alcohol.No other by-products were detected by gas chromatography.Once the hydrogen peroxide was consumed completely,the catalyst precipitated from solvent,and the results of the catalyst recycle showed that the catalyst had high stability.     

镍铁氰化物纳米粒子的合成及其多相催化无溶剂条件下苯甲醇氧化的潜能(英文)

Nickel hexacyanoferrate nanoparticles were synthesized and characterized using elemental analysis, thermal analysis, infrared spectroscopy, and X-ray diffraction. A FE-SEM image of the nickel hexacyanoferrate showed that it consists of nearly spherical particles with sizes ranging from 30 to 70 nm. The synthesized material was found to be a heterogeneous catalyst useful for the solvent-free oxidation of benzyl alcohol with H2O2 as an oxidant. A 36% conversion of benzyl alcohol to benzaldehyde was achieved under optimized reaction conditions using specific parameters such as the amount of catalyst, the temperature, the benzyl alcohol to H2O2 molar ratio, and the reaction time.     

Catalytic Membranes and Membrane Reactors： An Integrated Approach to Catalytic Process with a High Efficiency and a Low Environmental Impact

The design of new heterogeneous photooxygenation systems able to employ visible light,oxygen,mild temperatures,and solvent with a low environmental impact has been investigated. In particular,the heterogenization of decatungstate (W10O4-32),a polyoxometalate with photocatalytic activity in oxidation reactions,has been carried out in polymeric membranes of polyvinylidenefluoride. The polymeric catalytic membranes prepared by phase inversion technique have been successfully applied in the aerobic mineralization of phenol in water,which was used as an example of organic pollutant. In order to evaluate the effect of the polymeric environment on the overall catalyst behavior,we have also heterogenized the decatungstate (opportunely functionalized) in perfluorinated membrane made of Hyflon. The photocatalytic composite membranes are characterized by different and tuneable properties depending on the nature of the polymeric micro-environment,in which the catalyst is confined. Moreover,the selective separation function of the membrane results in enhanced performance in comparison with homogeneous reactions.     

CO oxidation on supported platinum group metal(PGM) based nanoalloys

The oxidation of carbon monoxide is widely investigated for realistic and potential uses in energy production and environmental processes.As a probe reaction to the surface properties,it gives an insight into the relationship between the structure of active phase and catalytic performance.Noble metals alloyed with certain transition metals in the form of a nanoalloy exhibit enhanced catalytic activity for various reactions,especially when simultaneous activation of oxygen and CO is involved.This article highlights some of these insights into nanoalloy catalysts in which platinum group metal(PGM)is alloyed with a second and/or third transition metal(M/M′=Co,Fe,V,Ni,Ir,etc.),for catalytic oxidation of carbon monoxide in a gas phase.Recent studies have provided important insights into how the atomic-scale structures of the nanoalloy catalysts operate synergistically in activating oxygen and maneuvering surface oxygenated species.The exploration of atomic-scale chemical/structural ordering and coordination in correlation with the catalytic oxidation properties based on findings from ex-and in-situ synchrotron X-ray techniques is emphasized;for example,high-energy X-ray diffraction coupled to atomic-pair distribution function and X-ray absorption fine-structure spectroscopic analysis.The understanding of the detailed active sites of the nanoalloys has significant implications for the design of low-cost,active,and durable catalysts for sustainable energy production and environmental processes.     

Development of Cu foam-based Ni catalyst for solar thermal reforming of methane with carbon dioxide

Using solar energy to produce syngas via the endothermic reforming of methane has been extensively investigated at the laboratory- and pilot plant-scales as a promising method of storing solar energy. One of the challenges to scaling up this process in a tubular reformer is to improve the reactor's performance, which is limited by mass and heat transfer issues. High thermal conductivity Cu foam was therefore used as a substrate to improve the catalyst's thermal conductivity during solar reforming. We also developed a method to coat the foam with the catalytically active component NiMg_3AlO_x. The Cu foam-based NiMg_3AlO_x performs better than catalysts supported on SiSiC foam, which is currently used as a substrate for solar-reforming catalysts, at high gas hourly space velocity(≥400,000 mL/(g·h)) or at low reaction temperatures(≤ 720 °C). The presence of a γ-Al_2O_3 intermediate layer improves the adhesion between the catalyst and substrate as well as the catalytic activity.     

Promoting effect of chloride ions on selective oxidation of methanol to methyl formate over zirconia-supported ruthenium oxide catalysts

The effect of chloride ions on a monoclinic ZrO₂-supported RuO_x（RuO_x/m-ZrO₂） catalyst with a Ru surface density of 0.3 Ru/nm² was studied in the selective oxidation of methanol to methyl formate（MF） at a low temperature of 373 K.The m-ZrO₂ support was Cl-free,and Cl^- ions were introduced into the RuO_x/m-ZrO₂ catalyst by impregnation with zirconium oxychloride or ammonium chloride and subsequent thermal treatment in air at 673 K.The structures of these catalysts were characterized by X-ray diffraction,Raman and X-ray photoelectron spectroscopies.Their reducibility was probed by temperature-programmed reduction in H₂.The RuO_x domains were present as highly dispersed RuO₄^2- structure on m-ZrO₂ with similar reducibility for the RuO_x/m-ZrO₂ samples irrespective of modification with or without Cl^- ions.Introduction of appropriate amounts of zirconium oxychloride into RuO_x/m-ZrO₂ led to a remarkable increase in the methanol oxidation rate and MF selectivity,whereas introduction of ammonium chloride or zirconyl nitrate significantly inhibited the catalytic performance of RuO_x/m-ZrO₂.The promoting effect of Cl^- ions derived from zirconium oxychloride can be tentatively attributed to their roles in facilitating the adsorption of methanol and desorption of MF product or its intermediates.This finding provides novel insights into the promoting effect of Cl ions on oxides-based catalysts for selective oxidation reactions.     

TARNISH AND PROTECTION OF SILVER DEPOSIT——MECHANISM AND METHOD

The mechanism of tarnish caused by exposure to light and Na_2S solution treatment on silver-electroplated deposit and the antitarnish effects of various antitarnish agents have been investigated in this paper. The results showed that 1-phenyl-5-mercaptotetrazole (PMTA) has excellent antitarnish effect for UV light and H_2S tests.The studies of XPS and AES and UV absorption spectra showed that PMTA can absorb effectively UV light and form a dense surface film which can prevent effectively the reactions between silver deposit with corrosive media.Antitarnish surface film could be composed of a polynuclear coordination polymeric compound with structure unit approximate to [Ag_3(PMTA)]. according to the depth dependence of percent component (C%) and sputtering time.     

Bimetallic Au-Pd NPs Embedded in MOF Ultrathin Nanosheets with Tuned Surface Electronic Properties for High-performance Benzyl Alcohol Oxidation

Bimetallic Au-Pd nanoparticles(NPs) with synergistic effect between Au and Pd atom have shown excellent catalytic activity toward benzyl alcohol oxidation. The catalytic activities of metal NPs supported within metal-organic frameworks (MOFs) are affected by the electronic interactions between metal NPs and MOFs. Taking the advantages of ultrathin nanosheets, we confine the highly dispersed Au-Pd NPs within ultrathin nanosheets of MOF-Ni(NMOF-Ni) to fabricate Au_xPd_y@NMOF-Ni as catalysts. Under base-free and atmospheric pressure conditions, the as-prepared Au_xPd_y@NMOF-Ni catalysts exhibit superior activity and selectivity for benzyl alcohol oxidation. This work highlights the synergistic effects among different components in composite catalysts effectively improving the activity and offers a new way for designing efficient catalysts toward benzyl alcohol oxidation.     

疏水性Cosalen/SBA-15的制备及在甲苯选择性氧化中的应用

以介孔分子筛SBA-15为载体, 先采用γ-氨丙基三乙氧基硅烷(APTES)进行氨基硅烷化修饰, 然后经甲基三乙氧基硅烷(MTES)疏水修饰后固载双水杨醛缩乙二胺合钴配合物(Cosalen). 采用傅里叶变换红外光谱、 紫外-可见漫反射光谱、 X射线光电子能谱、 元素分析、 等离子体发射光谱、 X射线衍射和氮气物理吸附等手段对制备的固载型催化剂Cosalen/SBA-15进行了物相结构和修饰程度的表征, 并考察了样品对甲苯、 苯甲醛和苯甲醇的吸附性能及在甲苯液相氧化反应中的催化性能. 结果表明, 固载型催化剂Cosalen/SBA-15的介孔结构和孔道有序性保持良好, Cosalen通过与氨基配位固载在修饰后的载体SBA-15上, 且高度分散, 氨基硅烷化和甲基修饰明显增强了其表面疏水性能, 对苯甲醛和苯甲醇的吸附量降低. 疏水性Cosalen/SBA-15协同N-羟基邻苯二甲酰亚胺(NHPI)催化甲苯液相分子氧氧化反应, 无溶剂体系在130 ℃下反应2 h, 甲苯转化率达到16.0%, 产物中苯甲醛和苯甲醇的总选择性为32.0%, 在一定程度上抑制了极性产物深度氧化为苯甲酸. 高温不利于苯甲醛和苯甲醇选择性的提高, 降低温度至110 ℃, 甲苯转化率达到12.9%时, 苯甲醛和苯甲醇的总选择性提高到43.9%.     

富氮空心蠕虫状碳材料的合成及其苯甲醇非金属选择性催化氧化的高活性

Carbon materials have become one of the research hotspots in the field of catalysis as a typical representative of non-metallic catalytic materials. Herein, a facile synthetic strategy is developed to fabricate a series of hollow carbon nanoworms (h-NCNWs) that contain nitrogen up to 9.83 wt% by employing graphitic carbon nitride (g-C₃N₄) as the sacrificing template and solid nitrogen source. The h-NCNWs catalysts were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), N₂ adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric (TG), Raman spectra, and X-ray photoelectron spectroscopies (XPS). The catalytic activities of the h-NCNWs catalysts for selective oxidation of benzyl alcohol with O₂ were also evaluated. The characterization results revealed that the h-NCNWs catalysts displayed a unique hollow worm-like nanostructure with turbostratic carbon shells. The nitrogen content and shell thickness can be tuned by varying the relative ratio of resorcinol to g-C₃N₄ during the preparation process. Furthermore, nitrogen is incorporated to the carbon network in the form of graphite (predominantly) and pyridine, which is critical for the enhancement of the catalytic activity of carbon catalysts for the selective oxidation of benzyl alcohol. At a reaction temperature of 120 ℃, a 24.9% conversion of benzyl alcohol with > 99% selectivity to benzaldehyde can be achieved on the h-NCNWs catalyst prepared with a mass ratio of resorcinol to g-C₃N₄ of 0.5. However, the catalytic activities of the h-NCNWs catalysts were dependent on the amount of N dopants, in particular graphitic nitrogen species. The conversion of benzyl alcohol markedly decreased to 13.1% on the h-NCNWs catalyst prepared with a mass ratio of resorcinol to g-C₃N₄ of 1.5. Moreover, the h-NCNWs catalyst showed excellent stability during the reaction process. The conversion of benzyl alcohol and the high selectivity to aldehyde can be kept within five catalytic runs over the h-NCNWs0.5 catalyst. These results indicate that rationally designed carbon materials have great potential as highly efficient heterogeneous catalysts for oxidation reactions.     

Progress and Prospect of Photothermal Catalysis

Recently, solar-driven synthesis due to its energy-saving and environmentally friendly advantages has attracted more and more attention, whereas the low solar-to-chemical conversion efficiency significantly hindered its development. New effective options that fully utilize full-band sunlight are urgently needed. Novel photothermal catalysis combined with the advantages of photocatalysis and thermalcatalysis can improve the utilization efficiency of solar energy and lower the reaction temperature, thus becoming a promising technology. This review divides photothermal catalysis into photo-assisted thermalcatalysis, thermal-assisted photocatalysis, and photothermal synergistic catalysis. Furthermore, the catalytic mechanical understanding of how photothermal affects the catalytic property of different applications(e.g., water splitting, CO₂/N₂ reduction, and environmental treatment) was also summed up and discussed in detail. The discussion ends with unsolved challenges in photothermal catalysis, particularly emphasizing the effect of temperature or sunlight on catalytic performance.     

金属卟啉/MgAl水滑石催化醇选择性氧化制备羰基化合物

将MgAl水滑石引入到金属四苯基卟啉(MTPPs,M=Co,Fe,Mn,Ni)催化氧化体系中,实现了醇的选择性氧化。 结果表明,在分子氧/异丁醛体系中,CoTPP在苯甲醇氧化制苯甲醛反应中表现出优异的催化活性,MgAl水滑石添加剂可有效地提高醛的选择性。 在苯甲醇1 mmol、乙腈2 mL、CoTPP 5 mg、MgAl水滑石18 mg、异丁醛5 mmol、反应温度60 ℃、氧气气氛下反应2 h,苯甲醇的转化率和苯甲醛的选择性分别达到94%和92%。 另外,此催化体系在其它醇类化合物的氧化反应中也具有较好催化活性。     

Co3O4/Ti电催化膜电极制备及其苯甲醇催化氧化性能

本文采用浸渍涂覆法成功制备出多孔Ti负载纳米Co₃O₄电催化膜电极（Co₃O₄/Ti）,以该膜电极为阳极,辅助电极为阴极,构建电催化膜反应器（electrocatalytic membrane reactor,ECMR）用于可控催化氧化苯甲醇制备苯甲醛和苯甲酸,并考察了 Co₃O₄/Ti 膜电极结构、电化学性能以及ECMR不同操作参数对苯甲醇转化率、苯甲醛和苯甲酸选择性的影响. 结果表明,负载Co₃O₄纳米颗粒可以显著提高Ti膜电极的电化学性能和催化活性. 在常温常压下,当反应物苯甲醇浓度为10 mmol·L^-1,pH为7.0,停留时间为5.0 min,电流密度为2.5 mA·cm^-2,苯甲醇的转化率达到49.8%,苯甲醛选择性为51.5%,苯甲酸选择性为23.6%.     

基于单原子催化剂的光热催化转化：原理和应用

在以碳中和为目标的全球共识下,太阳能作为一种取之不竭用之不尽的绿色环保能源被认为是替代传统化石燃料最有潜力的方式。在各种太阳能转换技术中,光热催化不仅可以最大化利用太阳能,在光场和热场双重驱动力作用下,还可以显著提升化学反应速率,引起广泛的研究兴趣。以孤立的单个原子均匀分散在载体上形成的单原子催化剂具有100%原子利用率、优异的催化活性、热稳定性等优势。因此,将单原子催化剂应用于光热催化开始受到越来越多的关注。本综述介绍了光催化、热催化和光热催化的基本原理和特征,同时列举一些典型的例子。随后以不同载体作为分类标准,总结了单原子光热催化应用的前沿研究进展。最后,提出了该催化体系所面临的挑战和未来的发展方向。本文旨在全面了解单原子催化剂在太阳能驱动光热催化领域的研究现状并为未来发展提供可行的建议。     

Near Infrared Light-to-Heat Conversion for Liquid-Phase Oxidation Reactions by Antimony-Doped Tin Oxide Nanocrystals

Effective utilization of the sunlight for chemical reactions is pivotal for dealing with the growing energy and environmental issues. So far, much effort has been focused on the development of semiconductor photocatalysts responsive to UV and visible light. However, the near infrared and infrared (NIR-IR) light occupying ∼50 % of the solar energy has usually been wasted because of the low photon energy insufficient for the band gap excitation. Antimony doping into SnO₂ (ATO) induces strong absorption due to the conduction band electrons in the NIR region. The absorbed light energy is eventually converted to heat via the interaction between hot electrons and phonons. This Concept highlights the photothermal effect of ATO nanocrystals (NCs) on liquid-phase oxidation reactions through the NIR light-to-heat conversion. Under NIR illumination even at an intensity of ∼0.5 sun, the reaction field temperature on the catalyst surface is raised 20–30 K above the bulk solution temperature, while the latter is maintained near the ambient temperature. In some reactions, this photothermal local heating engenders the enhancement of not only the catalytic activity and selectivity but also the regeneration of catalytically active sites. Further, the photocatalytic activity of semiconductors can be promoted. Finally, the conclusions and possible subjects in the future are summarized.     

光电解水制氢耦合生物质醇/醛氧化的研究进展

生物质醇/醛是一类重要的生物基平台化合物, 通过催化氧化重整可将其进一步转化为高值含氧化学品或燃料. 太阳能驱动的光电催化技术是实现生物质醇/醛氧化最为绿色高效的途径之一. 与传统光电解水制氢相比, 利用生物质醇/醛氧化来替代阳极析氧过程不仅可以提高阳极产物的附加值, 同时可以提升太阳能到氢能的转化效率. 因此, 光电解水制氢耦合生物质醇/醛氧化对绿氢提效降本和高值化学品合成具有重要意义. 本文综合评述了光电解水制氢耦合生物质醇/醛的氧化反应机理, 总结了目前光电催化技术在生物质醇/醛氧化方面的研究进展, 最后对该领域所面临的机遇和挑战进行了展望.     

Bimetallic Au/Pd catalyzed aerobic oxidation of alcohols in the poly(ethylene glycol)/CO2 system

Bimetallic Au/Pd nanoparticles were prepared and used to catalyze oxidation of alcohols in the poly(ethylene glycol) (PEG)/CO₂ biphasic system using O₂ as the oxidant without adding any base. The catalytic activity of Au/Pd bimetal with different mole ratios was studied using benzyl alcohol as the substrate. It was found that bimetallic Au/Pd nanoparticles with Au:Pd=1:3.5 had higher catalytic activity than monometallic Au, Pd and the bimetallic Au/Pd nanoparticles with other molar ratios. The effect of CO₂ pressure on the oxidation of benzyl alcohol and 1-phenylethanol in PEG/CO₂ was investigated. It was demonstrated that CO₂ pressure could be used to tune the conversion and selectivity of the reactions effectively. α,β,-Unsaturated alcohols were also studied and found to be more reactive than benzyl alcohol and 1-phenylethanol. Recycling experiments showed that the Au/Pd/PEG/CO₂ catalytic system could be recycled at least four times without reducing the activity. In addition, the catalytic system is clean and the products can be separated easily.