State-of-the-art technology: Recent investigations on laser-mediated synthesis of nanocomposites for environmental remediation

In both developing and industrialized/developed countries, various hazardous/toxic environmental pollutants are entering water bodies from organic and inorganic compounds (heavy metals and specifically dyes). The global population is growing whereas the accessibility of clean, potable and safe drinking water is decreasing, leading to world deterioration in human health and limitation of agricultural and/or economic development. Treatment of water/wastewater (mainly industrial water) via catalytic reduction/degradation of environmental pollutants is extremely critical and is a major concern/issue for public health. Light and/or laser ablation induced photocatalytic processes have attracted much attention during recent years for water treatment due to their good (photo)catalytic efficiencies in the reduction/degradation of organic/inorganic pollutants. Pulsed laser ablation (PLA) is a rather novel catalyst fabrication approach for the generation of nanostructures with special morphologies (nanoparticles (NPs), nanocrystals, nanocomposites, nanowires, etc.) and different compositions (metals, alloys, oxides, core-shell, etc.). Laser ablation in liquid (LAL) is generally considered a quickly growing approach for the synthesis and modification of nanomaterials for practical applications in diverse fields. LAL-synthesized nanomaterials have been identified as attractive nanocatalysts or valuable photocatalysts in (photo)catalytic reduction/degradation reactions. In this review, the laser ablation/irradiation strategies based on LAL are systematically described and the applications of LAL synthesized metal/metal oxide nanocatalysts with highly controlled nanostructures in the degradation/reduction of organic/inorganic water pollutants are highlighted along with their degradation/reduction mechanisms.     

Improvement of Ni-Cermet performance of protonic ceramic fuel cells by catalyst

Generally, the NiO composite anode becomes porous after reduction. To infiltrate additional catalysts such as Pd into the NiO-composite anode before reducing NiO to Ni, a porous NiO composite anode for protonic ceramic fuel cells (PCFCs) was fabricated in this study. The porous NiO composite was fabricated by adding graphite as a pore former along with CuO as a sintering agent. The addition of graphite increased the porosity of the NiO composite anode but resulted in poor sinterability, which was addressed by adding CuO as a sintering agent to the NiO composite anode. The Pd catalyst was added to the NiO-composite anode before reducing NiO to Ni. The composite anode for PCFC with three components, namely Ni, protonic ceramics, and a Pd catalyst, was obtained by reducing NiO to Ni during the measurement. The addition of the Pd catalyst improved the anode performance in methane fuel and hydrogen fuel by enhancing the catalytic activity for the electrochemical reaction on the surface.     

Review on synthesis of porous TiO2-based catalysts for energy conversion systems

Porous TiO₂-based catalysts have recently received remarkable attention in the field of energy conversion systems, including hydrogen/oxygen evolution reaction, oxygen/nitrogen reduction reaction, and photodegradation of pollutants owing to their unique structure, large surface area, and good chemical stability. In this report, we review existing research on porous TiO₂-based catalysts for energy conversion systems during the past four years. First, the advantages of porous TiO₂-based catalysts are introduced. Next, the synthetic approaches in developing porous TiO₂-based catalysts are summarized. The different types of energy conversion systems based on porous TiO₂-based catalysts are then presented. Finally, the challenges and future perspectives in synthesizing porous TiO₂-based catalysts are discussed.     

SO_4~(2-)/TiO_2-Hβ固体超强酸催化合成乙酸正丁酯

采用均匀沉淀法制备的SO24-/TiO2-Hβ复合型固体超强酸催化剂应用于乙酸正丁酯的合成中,得出最佳合成条件为反应时间4h,原料正丁醇与乙酸的摩尔配比1.3∶1,催化剂用量为乙酸用量的3%,乙酸正丁酯的收率95.6%。     

Direct thermochemical liquefaction of microcrystalline cellulose by sub- and supercritical organic solvents

Direct thermochemical liquefaction of microcrystalline cellulose was carried out using sub- and supercritical solvents in a batch reactor. The decomposition efficiency of dodecane and m-xylene widely used in petrochemical industries was compared to that of methanol and 1,4-dioxane. At 400 °C, the conversion in methanol was the highest (92 wt% including gaseous products), but the operating pressure was too high. m-Xylene at the same temperature showed the conversion of 71.5 wt% with a lower number of products and milder pressure. Hydrogen contributed to the increase of the total conversion by 3–8% in m-xylene and methanol, compared with the results without adding any additional gas or with nitrogen pressurization. An acid-modified silica catalyst led to a significant increase of conversion in the supercritical methanol, but its effect was negligible in the aprotic solvents. The product compounds and property of solid residue depended on the supercritical solvents applied. The thermal-treated char after liquefaction in m-xylene, dodecane and 1,4-dioxane was an effective adsorbent for CO₂ adsorption, showing the level comparable with activated carbons.     

β-羟乙基乙二胺环化合成哌嗪

本文研究了β 羟乙基乙二胺的催化加氢环合反应及几种铜系催化剂环合反应的催化性能。以甲苯为溶剂可显著提高β 羟乙基乙二胺环合生成哌嗪的选择性。反应的工艺参数优化结果表明 ,以Cu/γ Al2 O3 为催化剂、甲苯为溶剂、氢气初压3 0MPa和反应温度 1 80℃～ 1 90℃时 ,哌嗪收率可稳定在 85 %以上     

C1化学工业中的贵金属催化剂

叙述了贵金属催化剂在C     

Surface Properties and Catalytic Performance of La0.8K0.2CuxMn1–xO3 for Simultaneous Removal of NOx and Soot

The influence of copper substitution in La_0.8K_0.2Cu_xMn_1–xO₃ on its catalytic performance for simultaneous removal of NO_x and soot under oxygen rich conditions was investigated. A series of catalysts was prepared and then characterized by XRD, SEM, BET, and XPS. The temperature programmed reaction (TPR) method was used to evaluate the catalytic performance of the catalysts. XRD results show that the partial substitution of Cu for Mn promotes the formation of perfect perovskites. SEM and BET results demonstrate that appropriate copper substitution enhances the porosity and increases the specific surface area, leading to conditions which are favorable for heterogeneous catalysis. XPS results indicate that a fraction of the Mn³⁺ is converted to Mn⁴⁺ on the addition of low levels of Cu. By correlation of the physicochemical properties and the catalytic performance, a large specific surface area, high porosity, high content of Mn³⁺ and synergistic effects of Mn³⁺ and Cu²⁺ are seen to favor the simultaneous catalytic removal of NO_x and soot.