Reduction of Surface Nitrates via C3H6 Oxidation Over a Pt/Al2O3 Catalyst

Reduction of surface nitrates with C₃H₆ on a Pt/Al₂O₃ catalyst was investigated using diffuse reflectance infrared spectroscopy (DRIFTS) and a reactor system designed for monolith-supported catalysts. C₃H₆ oxidation was inhibited by the presence of NO, and vice versa, and data indicate that adsorbed NO_X reacted with gas phase C₃H₆. DRIFTS results confirm reaction between C₃H₆ and surface nitrates with linear nitrites as the reaction products. Data show that Pt is required for this reaction, which suggests the nitrates in proximity to the Pt particles are affected/relevant.     

Effect of Pt and Ba content on NO x Storage and Reduction Over Pt/Ba/Al2O3

Effects of Pt and Ba content of Pt/Ba/Al₂O₃ on NO _x storage reduction (NSR) catalyst were investigated by means of kinetic analysis of surface nitrates using in situ FT/IR. Turnover frequencies of both storage and reduction of nitrate were significantly enhanced at higher Ba content, while those were higher at lower Pt content below 0.2 wt%.     

Oxygen Reduction Reaction on Pt and Pt Bimetallic Surfaces: A Selective Review

In this review we selectively summarize recent progress, primarily from our laboratory, in the development of the oxygen reduction reaction (ORR) catalysis on well‐defined surfaces. The focus is on two type of metallic surfaces: platinum single crystals and bimetallic surfaces based on platinum. The single crystal results provide insight into the effects of the platinum structure on the kinetics of the ORR, and create a fundamental link between the specific activity of Pt (rate per unit area) and particle size (for various particle shapes). The results show that the structure sensitive kinetics of the ORR arise primarily due to structure sensitive adsorption of anions. In the absence of specific adsorption, such as in Nafion polymer electrolyte, no particle size effect is expected. The knowledge of the electrocatalysis of the ORR on model bimetallic surfaces on Pt‐Ni and Pt‐Co bulk alloys was used to resolve the enhanced ORR kinetics on supported Pt‐Ni and Pt‐Co catalysts. Finally, we show that the ORR on platinum modified with pseudomorphic Pd metal film in alkaline solution is the best catalysts ever used in O₂ reduction. For both bimetallic systems, we demonstrated that the ability to make a controlled and well characterized arrangement of two elements in the electrode surface region presage a new era of advances in the ORR electrocatalysis.     

载体处理对Pt/C催化剂的选择性加氢性能影响

研究了活性炭处理方式对以其为载体制备的铂炭催化剂性能的影响,以对氯硝基苯催化加氢制备对氯苯胺反应为模型反应对催化剂的性能进行评价。结果表明,经过处理的活性炭制备的铂炭在对氯硝基苯加氢反应中表现出的催化性能更高,5%NaOH在80℃下处理2 h的活性炭可以达到最佳效果,所制备的Pt/C催化剂重复使用4次,对氯苯胺收率在99%以上,脱氯率在0.3%以下。     

选择性催化还原脱硝催化剂失活综述

氮氧化物污染物的存在,威胁着我国的环境安全性,给人们的日常生产生活带来了一定的影响。因此,需要SCR脱硝系统的合理构建,对其中催化剂的应用概况进行分析,总结出催化剂的失活原因,从而为脱硝效率提高提供保障。基于此,对选择性催化还原脱销催化剂失活进行系统阐述。     

Ni-Mo/TiO_2-Al_2O_3催化剂的催化裂化轻汽油选择性加氢

制备了以TiO2/Al2O3为载体的镍基双金属选择性加氢催化剂,并用于催化裂化轻汽油的选择性加氢反应。考察了反应工艺条件对催化剂性能的影响,得出最佳的反应条件为:压力为2.0 MPa,反应温度为80℃,氢油比为40(体积比),空速为5 h-1。催化裂化轻汽油中二烯烃转化率达到98%以上。制备的选择性加氢催化剂具有良好的活性和选择性,其可以在选择性加氢领域获得应用。     

Pt/Al_2O_3-TiO_2催化剂催化氯代硝基苯选择加氢活性探究

氯代苯胺(CAN)是染料、杀虫剂和医药等生产过程中的一种重要中间体,在化学工业、医药等行业有着广泛的应用。因此,研发合成氯代苯胺催化剂成为该领域的研究热点。采用浸渍-还原法制备了Pt基催化剂,以氯代硝基苯(CNB)为反应底物,在30℃、常压下系统考察了载体组成、载体焙烧温度、添加不同的水量等因素对催化剂加氢性能的影响,并运用XRD对复合氧化物载体进行表征。     

Gas Sensing Characteristics of Porous ZnO and Pt/ZnO Ceramics

Changes in resistivity and chemical changes in reducing gases were measured for porous zinc oxide ceramics with and without a platinum catalyst at 300° and 400°C to examine the gas sensing mechanism and the effect of platinum additions. Reducing gases were oxidized to CO₂ and Hz₂ on the sensor surfaces. Platinum addition promoted the oxidation of reducing gases but did not lead to an increase in the resistivity change at 400°C. The reaction sequences for the gas sensing process are proposed, taking into account partially oxidized intermediates of hydrocarbons and oxidation on platinum without an electron transfer process.     

Efficient and Selective Hydrogenation of 5-Hydroxymethylfurfural to 2,5-Dimethylfuran Over a Non-noble CoNCx/NiFeO Catalyst

Catalysis Letters - Currently, there is tremendous interest in the discovery of efficient and low-cost catalysts for the selective hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) to...     

Selective Hydrogenation of Benzene to Cyclohexene Over Colloidal Ruthenium Catalyst Stabilized by Silica

A colloidal ruthenium catalyst stabilized by silica was prepared through microemulsion processing. Ruthenium colloids with particle size about 4 nm are highly dispersed in silica. The selective hydrogenation of benzene to cyclohexene was studied over the catalyst. Much higher activity and selectivity was obtained compared with its supported counterparts.     

Selective Catalytic Reduction of NOx with CH4 over the In/Sulfated TiO2 Catalyst

Tungstated TiO₂ (WTi), tungstated Fe₂O₃ (WFe), tungstated SnO₂ (WSn), sulfated TiO₂ (STi), sulfated Fe₂O₃ (SFe), and sulfated SnO₂ (SSn) are used as the support for the In and Pd catalysts for the SCR of NO with methane. It was found that the In/STi catalyst with a 2% indium loading showed the highest NO_x conversion (39% at 450 °C and 12,000 h⁻¹) among all of the catalysts studied. The acid strength of the STi support was very important for the formation of the InO⁺ site, which was thought to be the active site for NO reduction. The activity of the In/STi catalyst can be improved by increasing the surface area of the STi support. The most attractive feature of the In/STi catalyst is its high resistance for SO₂.