Mg/SiO2–Al2O3 supported nickel catalysts for the production of naphthenic hydrocarbon fuel by hydro-de-oxygenation of eugenol

Ni–Mg supported on both mesoporous Al₂O₃–SiO₂ (10) and γ-Al₂O₃ with Al₂O₃–SiO₂/Mg = 10 and γ-Al₂O₃/Mg = 10 ratio were prepared via wet impregnation method. The synthesized materials were characterized by XRD, N₂-sorption study, NH₃-TPD/H₂-TPR, FT-IR, DRS-UV and used in hydrodeoxygenation (HDO) of eugenol to produce hydrocarbons in a high pressure reactor. The reactant molecules could be facilitated to yield hydrocarbon fuel by active nickel active sites. The high oxygen removal efficiency of 75% was achieved with C9 hydrocarbon selectivity. Evaluation of catalytic properties such as high hydrogen consumption of 145 μmol/g (H₂-TPR) and enriched surface acidity of 2.35 mmol g⁻¹ (NH₃-TPD) was done. Ni/Mg-SA (10) exhibited the highest catalytic activity of 6.7 × 10⁻⁴ mol g⁻¹ s⁻¹ SRR and 10.27 s⁻¹ TOF respectively. The stability of catalysts was found to be 185 mg/g for Ni/Mg-SA (10) catalyst by TGA analysis. The structure-activity relationship was studied and the product distributions were also discussed in detail.     

Electrospun iron and nitrogen co-containing porous carbon nanofibers as high-efficiency electrocatalysts for oxygen reduction reaction

One-dimensional carbon nanofibers hold great promise to be potential candidates as high-efficiency electrocatalysts for oxygen reduction reaction (ORR). However, the catalysts in powder form always aggregate when preparing catalyst layer, which significantly hinders the extensive application. Herein, we report the facile synthesis of iron and nitrogen co-containing porous carbon nanofibers derived from PAN nanofibers existing as a flexible film via the electrospinning method, which could avoid aggregation when fabricating catalyst layer of fuel cells. The Fe–N/N–C NFs exhibit onset potential of 0.95 V and the half-wave potential of 0.78 V in 0.1 M KOH solution, suggesting superior electro-catalytic activity for ORR. Meantime, for Fe–N/N–C NFs catalyst, it shows a nearly four electron transferring process and the current density only decreases by 14.2% after 40,000 s. This easy and facile method provides a new idea for synthesis of oxygen reduction reaction with high-activity and good-stability.     

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.     

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.     

Quadruplex-Templated and Catalyzed Ligation of Nucleic Acids

Template-guided chemical reactions between nucleic acid strands are an important process in biomedical research. However, almost all of these reactions employ an oligonucleotide-templated approach that is based on the double-helix alignment. The moderate stability of the double helix makes this approach unsuitable for many chemical reactions, so alternative nucleic acid alignment mechanisms, demonstrating higher thermal and chemical stability, are desirable. Earlier, we described a noncovalent coupling mechanism between DNA strands through a quadruplex-and-Mg²⁺ connection (QMC). QMC is based on G-quadruplexes and allows unusually stable and specific interactions. Herein, a novel catalytic nucleic acid reaction, based on QMC, is described. This approach uses G-tetrads as a structural and recognition element without employing Watson-Crick complementarity rules at any stage of substrate/catalyst formation or interaction between them. Quadruplex-templated ligation can be achieved through the self-ligation of two nucleic acid strands, or through a quadruplex catalyst, which forms a G-triplex and specifically connects the strands. The process is extraordinarily robust and efficient. For instance, the ligation of carbodiimide-activated substrates can proceed in boiling solutions, and complete ligation is demonstrated within a minute. The quadruplex-templated and catalyzed reactions will create new opportunities for chemical reactions requiring harsh experimental conditions.     

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.     

Recycling GTL catalysts—A new challenge

The Fischer Tropsch synthesis of motor fuel from natural gas on a large scale may become significant in the near future for economic and environmental reasons. This process requires solid-phase catalysts containing large amounts of cobalt (catalyst) and traces of platinum group metals or rhenium (promoter). The economic data presented in this paper shows why recycling of those metals will be mandatory. Several recycling processes will be presented along with their technical challenges, most of which can be handled by Umicore using its know how and experience in the recycling of cobalt and the precious metals.     

低压甲醇羰基化制醋酸用Ni系催化剂及其制备工艺

介绍了用于低压甲醇碳基化制醋酸的Ｎｉ系催化剂进展概况。讨论了浸渍法制备Ｎｉ催化剂的工艺条件：催化剂中Ｎｉ含量以２．５％为宜；添加助剂和选择性能好的载体可提高Ｎｉ系催化剂的活性，助剂以Ｍｏ、Ｃｏ居多，载体以活性炭和碳分子筛为佳。在碳基化反应中，加入助催化剂（如碘甲烷）和氢气可提高催化剂的活性和选择性。提出了Ｎｉ系催化剂开发的两个主要方向。     

Raney Ni catalysts derived from different alloy precursors Part II. CO and CO2 methanation activity

Catalytic activity, in conjunction with reaction mechanism, was studied in the methanation of CO and CO₂ on three Raney Ni catalysts derived from different Ni-Al alloys using different leaching conditions. Main products were CH₄ and CO₂ in CO methanation, and CH₄ and CO in CO₂ methanation. Any other hydrocarbon products were not observed. Over all catalysts, CO methanation showed lower selectivity to methane and higher activation energy than CO₂ methanation. The catalyst derived from alloy having higher Ni content using more severe leaching conditions, namely higher reaction temperature and longer extraction time, showed higher specific activity and higher selectivity to methane both in CO and CO₂ methanation. In CO and CO₂ methanation on Raney Ni catalyst, catalytic activity was seen to have close relation with the activity to dissociate CO This paper was presented at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November 3 and 4,2004.     

A controlled atmosphere specimen holder for transmission electron microscopy

A controlled atmosphere specimen holder (CASH) has been developed for transmission electron microscopy (TEM) experiments. It is designed for studying the specimen's microstructure before and after treatments in various gases (H₂, O₂, N₂, Ar, etc.) at temperatures up to 600°C. The experiments are carried out without exposing the specimen to the ambient atmosphere. No modification of the electron microscope itself is needed. The same area of the specimen can be easily located after each gas treatment, thus the changes in the microstructure can be studied directly. Preliminary results on the cyclic oxidation and reduction of a model cobalt catalyst are presented.