作为高催化活性指标的V-Ti接口的度变化
Wanting Chen1, Shuang Chen1, Mengdan Song1
1SHU Center of Green Urban Mining & Industry Ecology, School of Environmental and Chemical Engineering, Shanghai University, No. 381 Nanchen Road, Shanghai 200444, P. R. China.
Inorganic chemistry
|October 3, 2024
概括
这项研究揭示了支持的TiO2催化剂的激活度 (ΔH) 与它们的催化活性相关. 更高的ΔH,特别是在暴露{001}方面的解剖酶上,表明更活跃的物种和更高的周转频率 (TOF).
科学领域:
- 材料科学 材料科学 材料科学
- 催化剂是一种催化剂.
- 表面化学 表面化学
背景情况:
- 支持的TiO2是普遍存在的催化剂,但其从前体到活性催化剂的激活过程仍未得到充分探索.
- 以前的研究主要集中在预成型催化剂的性能上,忽视了关键的初始激活阶段.
- 了解前体到催化剂的过渡对于优化催化剂设计和性能至关重要.
研究的目的:
- 为了研究支持的TiO2催化剂在激活期间的变化 (ΔH).
- 阐明 ΔH,负荷,TiO2晶相,面暴露和催化活性 (转换频率,TOF) 之间的关系.
- 为有效的催化剂设计提供关于活性物种和TiO2支持之间的相互作用的见解.
主要方法:
- 差异扫描热量计 (DSC) 用于测量前体到催化剂过渡期间的变化 (ΔH).
- 研究了不同TiO2多态体 (anatase,rutile,brookite) 上的不同 (V) 负荷 (0.1~5 wt%) 的变化.
- 进行了理论计算,以了解V嵌入在不同的解剖酶方面 ({001}, {101}, {100}).
主要成果:
- ΔH从10.13降低到4.13 kJ·mol-1随着V负荷从0.1增加到5重%的解剖酶.
- 在1重%V负载下,与鲁提尔和布鲁基特相比,解酶的 ΔH 值更高 (8.71 kJ·mol-1).
- 在解剖酶中增加 {001} 面的比率将 ΔH 增加到 9.65 kJ·mol-1,与更高的 TOF 相对应.
结论:
- 较高的 ΔH 表示在催化剂制备过程中形成更活跃的物种.
- 解剖酶的 {001} 方面在增强 ΔH 和随后的催化活性 (TOF) 中发挥着关键作用.
- 这项研究加深了对活跃物种支持相互作用的理解,指导了基于的高效催化剂的设计.
相关概念视频
Constant Pressure Calorimetry
Calorimetry is a technique used to measure the amount of heat involved in a chemical or physical process or to measure the heat transferred to or from a substance. The heat is exchanged with a calibrated and insulated device called the calorimeter. Calorimetry experiments are based on the assumption that there is no heat exchange between the insulated calorimeter and the external environment. The well-insulated calorimeters prevent the transfer of heat between the calorimeter and its external...
Enthalpy and Heat of Reaction
Combustion, commonly known as burning, is a reaction in which a substance reacts with an oxidizing agent, which in most cases is molecular oxygen, to liberate energy in the form of heat, light, or sound. The heat of combustion is also known as the enthalpy of combustion. The energy released when one mole of a substance undergoes complete combustion at constant pressure is called molar heat of combustion. Combustion reactions are exothermic; that is, they release energy, and their ΔH sign...
Turnover Number and Catalytic Efficiency
The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from 1 to 1000 molecules per second. Catalase has the known highest turnover number, capable of converting up to 2.8×106 molecules of hydrogen peroxide into water and oxygen per second. Lysozyme has the lowest known turnover number of half a molecule per second.
Chymotrypsin is a pancreatic enzyme that breaks down proteins during digestion. The...
Chymotrypsin is a pancreatic enzyme that breaks down proteins during digestion. The...
Thermodynamics: Chemical Potential and Activity
The effective concentration of a species in a solution can be expressed precisely in terms of its activity. Activity considers the effect of electrolytes present in the vicinity of the species of interest and depends on the ionic strength of the solution. The activity of a species is expressed as the product of molar concentration and the activity coefficient of the species.
The thermodynamic equilibrium constant is more accurately defined in terms of activity rather than concentration.
The thermodynamic equilibrium constant is more accurately defined in terms of activity rather than concentration.
Thermodynamics: Activity Coefficient
Activity is the measure of the effective concentration of the species in solution. It can be expressed as the product of the molar concentration of the species and its activity coefficient. The activity coefficient is a dimensionless quantity and depends on the total ionic strength of the solution.
The activity coefficient is a measure of the deviation from ideal behavior. When the ionic strength of the solution is minimal, the activity coefficient of an ionic species is close to unity, making...
The activity coefficient is a measure of the deviation from ideal behavior. When the ionic strength of the solution is minimal, the activity coefficient of an ionic species is close to unity, making...
Heterogeneous Catalysis
Heterogeneous catalysis involves a catalyst in a different phase from the reactants. It is a process where the catalyst and the reactants are in distinct phases, typically solid and gas or liquid.Most heterogeneous catalysts are metals, metal oxides, or acids. The list includes transition metals like iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), manganese (Mn), tungsten (W), silver (Ag), and copper (Cu). These metals possess partially vacant d orbitals that...


