激光促进乙醇氧化偶联反应

用ＸＲＤ、ＩＲ和脉冲ＣＯ２激光，研究了在固体Ｃｕ２（ＰＯ４）（ＯＨ）ｔ Ｐｂ３（ＰＯ４）２表面上激光促进乙醇氧化偶联的反应性能。实验结果表明：乙醇的定位化学吸附态决定着反应产物的选择性，甲基吸附态（〉Ｐ＝０…Ｈ－ＣＨ２ＣＨ２ＯＨ）反应生成１，４－丁二醇，而羟基吸附态（〉Ｐｂ…ＯＨＣＨ２ＣＨ３）则生成乙烯；固体表面构造基元的振动结构是影响激光能量利用率的主要因素，Ｃｕ２（ＰＯ４）（ＯＨ）表面Ｐ＝Ｏ键     

SO4^2—／ZrO2超强酸催化剂的XPS研究

对ＸＰＳ技术对不同焙烧温度，不同Ｈ２ＳＯ４浓度制得的ＳＯ４＾２－／ＺｒＯ２和不同反应温度下反应后ＳＯ４＾２－／ＺｒＯ２超强酸催化剂的表面元素电子结合能及表面元素的相对含量进行了分析。结果表明，焙烧温度和反应温度对催化剂表面元素Ｚｒ，Ｏ，Ｓ的氧化态没有影响，但Ｚｒ，Ｏ的电子结合能随温度的升高而下降；Ｏ（－２）至少可归结为三种存在形式的氧；ＳＯ４＾２－可以在催化剂表面富集，且当Ｈ２ＳＯ４浓度为０．５ｍ     

二氧化碳加氢合成甲醇铜基催化剂表面组成的研究

本文分别采用ＸＲＤ、ＥＳＲ、ＸＰＳ和ＸＡＥＳ等技术对于二氧化碳加氢低压合成甲醇用ＣｕＯ，ＣｕＯ－ＺｎＯ，ＣｕＯ－ＺｎＯ－Ａｌ＿２Ｏ＿３，ＣｕＯ－ＺｎＯ－ＺｒＯ＿２催化剂在不同条件下表面Ｃｕ、Ｚｎ、Ａｌ、Ｚｒ的存在价态进行了深入分析。实验发现催化剂在还原前Ｃｕ以Ｃｕ￣２＋存在，在还原后和反应状态下以Ｃｕ￣０存在；Ｚｎ在还原后和反应状态下有部分被还原为Ｚｎ￣（２－δ）（０＜δ＜２），Ｚｒ和Ａｌ仍保持其还原前价态。催化剂的表面化学组成为：Ｃｕ￣０／Ｚｎ（２－δ）￣＋／Ｚｒ￣４＋／Ａｌ￣３＋／Ｏ￣２－。     

CO在YBa2Cu3Ox薄膜上吸附与加氢的研究

ＹＢａ２Ｃｕ３Ｏｘ（ｘ＝６－７）薄膜被合成在ＹＳＺ基底上，用ＦＴＩＲ，ＸＰＳ，ＸＲＤ等手段原位研究ＣＯ在薄膜上的吸附及加氢行为。ＣＯ吸附在Ｃｕ位置上，与ＹＢＣＯ体相中的Ｏ作用，生成表面ＣＯ２或－ＣＯＯ基团，导致ＹＢＣＯ中生产氧空位，使ＹＢＣＯ发生昌型转变，Ｃｕ＾２＋被还原为Ｃｕ＾＋或Ｃｕ＾０．ＹＢＣＯ中的氧空位有利于ＣＯ、ＣＯ２及Ｈ２的吸附。ＣＯ、ＣＯ２在ＹＢＣＯ膜上的加氢产物为ＣＨ３ＯＨ、ＣＨ３     

风化煤腐植酸与Ca(H2PO4)2相互作用机理的研究

采用化学法及ＩＲ、ＸＲＤ、ＸＰＳ等综合解析手段,研究了风化煤腐植酸（ＨＡ）、腐植酸钾（ＨＡ－Ｋ）与磷酸一钙「Ｃａ（Ｈ２ＰＯ４）２」之间的反应特征,探讨了二者的反应机理。结果表明,磷酸一钙与ＨＡ基本未发生反应,而与ＨＡ－Ｋ反应后生成ＫＨ２ＰＯ４以及ＨＡ与ＣａＨＰＯ４的有机－无机复合物,但该复合物不太稳定,在水溶液中易水解生成腐植酸钙（ＨＡ－Ｃａ）和Ｃａ（Ｈ２ＰＯ４）２。本研究将为研制以煤炭腐植酸为基     

钙矾石吸附水的模型及等温式

钙矾石３ＣａＯ·Ａｌ２Ｏ３·３ＣａＳＯ４·３２Ｈ２Ｏ是水泥熟料水化的重要产物．它易被空气中的ＣＯ２ 分解,常温下的分解反应为３ＣａＯ·Ａｌ２Ｏ３·３ＣａＳＯ４·３２Ｈ２Ｏ ３ＣＯ２ →３ＣａＣＯ３ Ａｌ２Ｏ３·ｘＨ２Ｏ ３（ＣａＳＯ４·２Ｈ２Ｏ） （２６ -ｘ）Ｈ２Ｏ分解机理［１ ,２］是：Ｈ２Ｏ先吸附在钙矾石表面的活性中心上,吸附态水再吸收ＣＯ２ 成为Ｈ２ＣＯ３ ,然后碳酸与钙矾石反应,实现碳化（即分解）．其分解速率［３］为ｖ＝ｋｐｃｏ２ ｐＨ２ｏ（１）可见水的吸附是钙矾石碳化分解的关键步骤,因此探讨…     

CO2在Cu-Ni/ZrO2-SiO2催化剂上的吸附与反应

采用表面反应改性法,制备了ＺｒＯ２－ＳｉＯ２（ＺｒＳｉＯ）表面复合物,用等体积浸渍法制备了ＺｒＳｉＯ担载的Ｃｕ－Ｎｉ双金属催化剂,用ＩＲ和ＴＰＤ技术,研究了ＣＯ２在其表面上的化学吸附与反应性能。实验结果表明：在Ｃｕ－Ｎｉ／ＺｒＳｉＯ催化剂ＣＯ２可形成线式吸附态、剪式吸附态和卧式吸附态;催化剂表面金属位Ｍ上的剪式吸附态ＣＯ２可与邻近的ｌｅｗｉｓ酸位Ｚｒ＾ｎ＋作用,形成ＣＯ２卧式吸附态Ｍ－（ＣＯ）－     

天然气和氧偶联制环氧乙烷催化剂的反应性能

研制了天然气和氧经偶联反应制环氧乙烷的Ａｇ－Ｂａ－Ｃｓ／Ａｌ２Ｏ３催化剂（ＮＥＯ－１）。用Ｎ２＋Ｏ２＋Ｃ２Ｈ４和偶联产物气加氧作原料气，在２５０℃，空速２５００ｈ＾－１时，乙烯转化率和ＥＯ选择性分别达到了３０％和８０％，ＮＥＯ－１催化具有适宜的比表面和孔结构，用ＸＰＳ分析发现，与新鲜的催化相比，经活化和反应后的催化剂表面的Ｂａ，Ｃｓ原子浓度增高，并具有较多的吸附氧物种。     

锰助剂对Fe／ZrO2催化剂F—T反应催化性能的影响

应用ＸＲＤ，ＸＰＳ，Ｍｏｓｓｂａｕｅｒ谱，ＴＰＲ，ＣＯ化学吸附ＣＯ－ＴＰＤ，ＣＯ＋Ｈ２反应性能测试等手段研究了锰助剂对Ｆ－Ｔ合成制低碳烯烃Ｍｎ－Ｆｅ／ＺｒＯ２催化剂结构及催化性能的影响。结果表明，与Ｆｅ／Ｚｒ催化相比，加锰助剂后的催化剂Ｆ－Ｔ反应催化活性上升，甲烷选择性降低，低碳烯烃选择性增加。     

CO2加H2合成甲醇Cu—Zn—O催化剂表面化学态研究

应用ＸＲＤ、ＥＳＲ、ＵＲＤＳ、ＸＰＳ及ＸＡＥＳ等手段研究了ＣＯ２加Ｈ２合成甲醇Ｃｕ－Ｚｎ－Ｏ催化剂在还原后和反应状态下的表面化学状态。结果表明，在还原及反应状态下，催化剂表面仅能检测到ＣＵ＾０，而未发现稳定的Ｃｕ＾２＋和Ｃｕ＾＋存在；ＺｎＯ被 部分还原产生低价锌Ｚｎ＾（２－δ）＋（０＜δ＜２）。关联活性测试结果认为：Ｃｕ＾ｏ／Ｚｎ＾（２－δ）＋Ｏ构成ＣＯ２加Ｈ２合成甲醇反应的活性中心。     

大气中一元酸催化亚硫酸分解反应的从头算及动力学研究

采用从头算的理论计算方法,在CCSD（T）/aug-cc-pVDZ//MP2/aug-cc-pVDZ水平下,对甲酸、乙酸、丙酸和硝酸催化亚硫酸分解成二氧化硫和水的微观反应机理进行了理论研究.结果表明,这4种一元酸均可使亚硫酸分解反应能垒显著降低,降低幅度由大到小的顺序为丙酸 > 乙酸 > 甲酸 > 硝酸.其中,丙酸甚至使反应能垒从裸反应时的99.84 kJ/mol降至27.24 kJ/mol.在此基础上,计算了200~320 K温度范围内4种一元酸催化亚硫酸分解反应的速率常数,并结合它们在大气中的实际浓度计算了有效速率常数.结果表明,在实际大气环境中,乙酸对亚硫酸分解反应的催化效果最为显著.当乙酸存在时,亚硫酸在室温下的大气寿命仅为0.02 s.     

Functionalization of beta-Ga2O3 nanoribbons: a combined computational and infrared spectroscopic study

The adsorption of H 2O, alcohols (CH 3OH and 1-octanol), and carboxylic acids (formic, acetic, and pentanoic) on beta-Ga 2O 3 nanoribbons has been studied using infrared reflection-absorption spectroscopy (IRRAS) and/or ab initio computational modeling. Adsorption energies and geometries are sensitive to surface structure, and hydrogen bonding plays a significant role in stabilizing adsorbed species. On the more stable (100)-B surface, computation shows that the physisorption of H 2O or CH 3OH is weakly exothermic whereas chemisorption via O-H bond dissociation is weakly endothermic. Experiment finds that a large fraction of a saturation coverage of adsorbed 1-octanol is displaced by exposure to acetic acid vapor. This is consistent with computational results showing that acids adsorb more strongly than methanol on this surface. The remaining alcohol, not displaced by acetic acid, suggests the presence of defects and/or (100)-A regions because computation shows that this less-stable surface adsorbs methanol more strongly than does the (100)-B. The nu(C-H) modes of adsorbed 1-octanol are easily detected whereas no adsorbed H 2O is observed even though H 2O and CH 3OH exhibit similar adsorption energies. It is inferred from this that the failure to detect H 2O on the dominant (100)-B surface results from the orientation of the physisorbed H 2O essentially parallel to the surface. Computation shows that this configuration is stabilized by H bonding. For chemisorbed formic acid, computation shows that a bridging carboxylate structure is favored over a bidentate or monodentate configuration. Computation also shows that chemisorption is favored on the (100)-A surface but physisorption is favored on the more stable (100)-B. Analysis of IRRAS data for acetic and pentanoic acids finds evidence for both types of adsorption. The carboxylate resists displacement by H 2O vapor, which suggests that carboxylic acids may be useful for functionalizing beta-Ga 2O 3 surfaces. The results provide insight into the interplay between surface structure and reactivity on an oxide surface and about the importance of hydrogen bonding in determining adsorbate structure.     

Production of formic and acetic acids from phenol by hydrothermal oxidation

Hydrothermal technology is a core environmental-protection technique which can be used for waste water treatment and biomass conversion. In this paper a novel idea, alkaline hydrothermal oxidation, is proposed for producing formic and acetic acids from wastewater containing phenolic compounds. The effects of the most important conditions??reaction temperature, reaction time, oxygen supply, and type of alkaline catalyst??on yields of formic and acetic acids were investigated. The results indicated that the optimum conditions for production of formic and acetic acids were: reaction temperature 300???C, reaction time 90?s, H₂O₂ equivalent to 60% oxygen, and NaOH concentration 1.5?mmol. Under the optimum conditions the yields of formic and acetic acids reached 4.8 and 23.5%, respectively. In addition, the effect of different alkalis on yields of formic and acetic acids was also investigated. The results showed that compared with use of NaOH addition of KOH had a more pronounced effect on improving the yield of acetic acid. This research indicated that high-value-added formic and acetic acids can be recovered as resources by hydrothermal oxidation of phenolic wastewater, and thus hydrothermal oxidation has high potential for converting phenolic compounds in wastewater into value-added products.     

Mechanistic study of electrocatalytic oxidation of formic acid at platinum in acidic solution by time-resolved surface-enhanced infrared absorption spectroscopy

Surface-enhanced infrared absorption spectroscopy (SEIRAS) combined with cyclic voltammetry or chronoamperometry has been utilized to examine kinetic and mechanistic aspects of the electrocatalytic oxidation of formic acid on a polycrystalline Pt surface at the molecular scale. Formate is adsorbed on the electrode in a bridge configuration in parallel to the adsorption of linear and bridge CO produced by dehydration of formic acid. A solution-exchange experiment using isotope-labeled formic acids (H(12)COOH and H(13)COOH) reveals that formic acid is oxidized to CO(2) via adsorbed formate and the decomposition (oxidation) of formate to CO(2) is the rate-determining step of the reaction. The adsorption/oxidation of CO and the oxidation/reduction of the electrode surface strongly affect the formic acid oxidation by blocking active sites for formate adsorption and also by retarding the decomposition of adsorbed formate. The interplay of the involved processes also affects the kinetics and complicates the cyclic voltammograms of formic acid oxidation. The complex voltammetric behavior is comprehensively explained at the molecular scale by taking all these effects into account.     

The effect of different monocarboxylic acids on the gelation behaviour of Cu ethoxide

Cu ethoxide becomes soluble in methoxyethanol when formic, acetic, or acrylic acid is added. For the complete dissolution, the minimum molar ratio of an acid to Cu ethoxide is two for formic acid (HOFA), and one for acetic (HOAC) or acrylic (HOAA) acid. The solutions of Cu ethoxide with any amounts of formic acid are incapable of forming gels. Those with acetic or acrylic acid/Cu ratio of 1 are able to convert to gels. For the range of the water concentration from 1.5 to 10 M, the gelation time is strongly dependent on [H₂O] for the solution with HOAC/Cu ratio of 1, while it is almost independent for the solution with HOAA. It is suggested that the differences in the behaviour of soluble Cu species derived from the three acids are attributed to different coordination forms and the bonding strength between ligands and copper ions.     

Calorimetric study of the reactions of n-alkylphosphonic acids with metal oxide surfaces

The reaction enthalpies for the solution-phase self-assembly of n-alkylphosphonic acids on the surfaces of TiO2 and ZrO2 have been determined using isothermal titration calorimetry at 298 K. The reaction enthalpies were negative (exothermic) for methyl- and n-octylphosphonic acids and positive (endothermic) for n-octadecylphosphonic acid with both metal oxides. The enthalpy/energy analysis showed that the net enthalpy of the formation of self-assembled monolayers (SAMs) at solid-liquid interface can be presented as follows: DeltaHr=-D-(DeltaHsol+DeltaHdil)-(ES-ESAM), where D is the binding energy of the SAM molecules with the solid; DeltaHsol and DeltaHdil are the enthalpies of dissolution and dilution; ES and ESAM are the surface energies of bare solid and SAM, respectively. This equation predicted an increase (and the sign change) of the reaction enthalpy as the alkyl group in n-alkylphosphonic acid increased, which explained the experimental data. Using this equation, the binding energy (D) in the SAMs of n-octyl- and n-octadecylphosphonic acids were estimated: 55+/-5 kJ/mol (for ZrO2) and 58+/-7 kJ/mol (for TiO2).     

超临界水中甲酸降解过程实验研究

在550℃~650℃,24 MPa~30 MPa,反应停留16 s~46 s的条件下,对初始浓度0.05 mol/L~0.70 mol/L的甲酸溶液在超临界水中的降解过程进行实验研究。结果表明,甲酸降解的气体产物为H2、CO2和CO,其中H2、CO2为主要产物。高温有利于甲酸降解和H2生成。温度较高(600℃)时,压力变化对甲酸降解无明显影响。在一定范围内延长反应时间可提高气体产物中H2的体积分数和碳气化率。甲酸初始浓度对甲酸降解机理有重要影响,浓度较低(0.1 mol/L)时,甲酸降解主要包含脱羧反应和脱羰反应两条反应路径,其中脱羧反应为主反应路径;浓度较高时则有许多副反应发生。碱性添加剂不利于甲酸降解生成H2。     

Formic acid electrooxidation on Pd in acidic solutions studied by surface-enhanced infrared absorption spectroscopy

A mechanistic study of electrocatalytic oxidation of formic acid on Pd in sulfuric and perchloric acids is reported. Surface-enhanced infrared absorption spectroscopy in the attenuated total reflection mode (ATR-SEIRAS) shows the adsorption of CO, bridge-bonded formate, bicarbonate, and supporting anions on the electrode surface. Poisoning of the Pd surface by CO, formed by dehydration of formic acid, is very slow and scarcely affects formic acid oxidation. The anions are adsorbed more strongly in the order of (bi)sulfate > bicarbonate > perchlorate, among which the most strongly adsorbed (bi)sulfate considerably suppresses formic acid oxidation in the double layer region. The oxidation is suppressed also at higher potentials in both acids by the oxidation of the Pd surface. Adsorbed formate is detected only when formic acid oxidation is suppressed. The results show that formate is a short-lived reactive intermediate in formic acid oxidation and is hence detected when its decomposition yielding CO(2) is suppressed. The high electrocatalytic activity of Pd can be ascribed to the high tolerance to CO contamination and also high catalytic activity toward formate decomposition.     

A HREELS study of the adsorption of formic acid on slightly oxidized Nb(110) surface

An investigation has been made on the adsorption and decomposition of formic acid on slightly oxidized Nb(110) surface (0/Nb atom ratio = 0.2) using high resolution electron energy loss spectroscopy (HREELS),and a corresponding surface reaction mode is given.At 140 K,formic acid of low exposure on such an Nb(110) surface decomposed to formate,which bonded on Nb in monodentate configuration,simultaneously some formate decomposed to CO,which adsorbed on the surface.Formic acid multilayers formed when the exposure was high.While the temperature was increased to above 190 K,multilayer formic acid desorbed,and the surface was covered with mon-odentate-bonded formate and CO.In the temperature range of 250-300 K,chemisorbed formate changed from monodentate configuration into bridging configuration and CO molecules disappeared.The decomposition of formate at higher temperatures led to the oxidation of Nb.The formate formed in the high exposure case was so stable that it did not decompose even the temperature wa     

磁性纳米复合氧化物固体酸催化剂的制备及酯化性能

固体酸催化剂的无腐蚀、环境友好和可循环使用等特点使其成为无机液体酸的最佳替代物.磁性纳米固体酸具有优于常规固体酸催化剂的催化活性及分离简单的特性.用共沉淀法分别合成了一系列三组分TiO2-Al2O3-Fe3O4(TAF)和CeO2-Al2O3-Fe3O4(CAF)及四组分ZrO2--Al2O3-Fe3O4(ZACF)磁性纳米复合氧化物固体酸催化剂,通过电感耦合等离子体原子发射光谱、比表面积测定、X射线衍射、透射电镜、热重分析和红外光谱等对其进行了表征,并利用酯化反应作为探针反应评价了其催化性能.结果表明,合成的磁性纳米固体酸催化剂在酯化反应中表现出很好的催化活性.