Synthesis Of Solid Catalysts Research Articles

Nested Metal Catalysts: Metal Atoms and Clusters Stabilized by Confinement with Accessibility on Supports.

Supported catalysts that are important in technology prominently include atomically dispersed metals and metal clusters. When the metals are noble, they are typically unstable-susceptible to sintering-especially under reducing conditions. Embedding the metals in supports such as organic polymers, metal oxides, and zeolites confers stability on the metals but at the cost of catalytic activity associated with the lack of accessibility of metal bonding sites to reactants. An approach to stabilizing noble metal catalysts while maintaining their accessibility involves anchoring them in molecular-scale nests that are in or on supports. The nests include zeolite pore mouths, zeolite surface cups (half-cages), raft-like islands of oxophilic metals bonded to metal oxide supports, clusters of non-noble metals (e.g., hosting noble metals as single-atom alloys), and nanoscale metal oxide islands that selectively bond to the catalytic metals, isolating them from the support. These examples illustrate a trend toward precision in the synthesis of solid catalysts, and the latter two classes of nested catalysts offer realistic prospects for economical large-scale application.

Synthesis of Solid Catalyst from Palm Empty Fruit Bunch for Production of Biodiesel through Esterification

Application of solid acid catalyst in biodiesel production gains much attention from researchers as it is suitable for most of the non-edible and low value oils which will significantly cut down the total production cost and reduce corrosion issue. In this research, biomass from palm empty fruit bunch is used as the carbon precursor to synthesis activated carbon (AC) before sulfonated by 4-benzenediazonium sulfonate (4-BDS) to produce solid acid catalyst. The synthesized catalysts were characterized and the performances were tested in esterification of palm fatty acid distillate (PFAD) to produce biodiesel. Scanning Electron Microscope (SEM) showed that a clear porous and rough surface was developed after calcination at relative low temperature (200 ° C) which favors the attachment of the acid active site. It also found that that the total acid sites of the catalyst increased when sulfanilic acid loading increased during sulfonation. In catalytic activity test, the result showed that catalyst calcined at 200 ° C and catalyst sulfonated with 15:1 sulfanilic acid to AC ratio was the optimum catalyst as they gave the highest biodiesel yield at 73.14%.

Synthesis of solid catalyst from natural calcite for biodiesel production: Case study of palm kernel oil in an optimization study using definitive screening design

A highly-active catalyst for biodiesel production was developed from calcite rock by calcination at different temperatures of 800°C (CCT800) and 900°C (CCT900). The calcination was to transform the metal carbonate in the calcite to metal oxides. The catalyst performance was evaluated through transesterification of palm kernel oil to palm kernel biodiesel (PKB), in an optimization study using a definitive screening design (DSD). The process conditions for the DSD were Methanol: oil molar ratio, reaction temperature, catalyst quantity, reaction time and calcite calcined temperature (CCT). Catalyst’s extent of reusability was investigated. The elemental composition for calcite catalyst calcined at 800°C (CCC800) and 900°C (CCC900) showed percentage composition of carbon, 21.11 and 22.84, oxygen, 40.37 and 38.78, magnesium, 15.17 and 13.34, silicon, 3.61 and 3.23, and calcium, 17.39 and 21.48, respectively which is an indication that the calcination temperature might not have affected the composition of the catalyst. The results showed that the catalyst is rich in essential ingredients (CaO and MgO) for biodiesel production. Its performance for biodiesel production gave an optimum yield of 97% PKB at optimal conditions of 6:1 (w/w) Methanol: oil molar ratio, reaction temperature 55°C, catalyst quantity 8% (w/w), reaction time 2 hours and CCT800. The catalyst was reused for eight cycles with greater activity of not <5% for PKB production. The PKB showed high-quality biodiesel as compared with the standard. Therefore, the calcite is a potential rock as a catalyst for biodiesel production.

Synthesis of solid catalyst from egg shell waste and clay for biodiesel production

Until now, energy consumption in Indonesia is almost entirely fulfilled by fossil fuels, thus, its availability will be limited and continue to decrease. To overcome these problems, development and utilization of renewable energy are required, one of which is biodiesel. Biodiesel can be prepared through transesterification reaction of vegetable oil using catalyst. In this research, a solid catalyst for biodiesel synthesis was prepared from chicken egg shell waste and clay. Optimization of the transesterification reaction of coconut (Cocos nucifera) oil to obtain biodiesel was also carried out. The formation of CaO/kaolin catalyst was confirmed based on the results of XRD and SEM-EDS. This catalyst is suitable for biodiesel synthesis from vegetable oils with lower FFA (free fatty acid) levels, i.e. coconut oil with FFA level of 0.18%. Based on FTIR result, FFA level and flame tests, it was found that biodiesel was successfully formed. Synthesis of biodiesel has the optimum conditions on reaction time of 16 hours and temperature of 64 °C, with oil: methanol ratio of 1: 15 and CaO/kaolin catalyst concentration of 0.9% in a reflux system.

Synthesis of Solid Catalysts with Spatially Resolved Acidic and Basic Molecular Functionalities

A synthetic procedure was developed to prepare dual acid–base catalysts on a single platform. Mesoporous SBA-15 was derivatized using known grafting chemistry via the following steps: (1) addition ...

Solvent-free synthesis of alumina supported cobalt catalysts for Fischer–Tropsch synthesis

A novel mechano-synthesis method has been elaborated in this work for the design of efficient cobalt-based Fischer–Tropsch catalysts. The process aims to reduce the total number of steps involved in the synthesis of solid catalysts and thus to avoid relevant toxic solutions generated during the catalyst preparation. The mechano-synthesis of the Co/Al2O3 catalyst was processed in a low-energy vibratory micro mill and high energy planetary ball mill. Porous spherical γ-aluminas (1860µm and 71µm mean particle diameter) were used in this work as host compounds. Co3O4 (3µm mean particle diameter) has provided guest particles for mechano-synthesis. The catalysts were characterized by textural (surface area, porosity and particle size) and structural analyses (X-ray diffraction, TPR, SEM-EDX and microprobe). The microprobe images show deposition of Co3O4 on the surface of the alumina and indicated no Co3O4 diffusion inside the alumina pores. SEM-EDX mapping illustrated that cobalt coating tended to occur on surface of rounded shape of cracked alumina fragments. After milling, the crystallite size of Co3O4 decreased to 15nm from 30 to 50nm. The TPR profiles indicated very low concentrations of inactive cobalt aluminate mixed compounds which are usually produced during the catalyst preparation by impregnation. In Fischer–Tropsch synthesis, the catalysts prepared using mechano-synthesis methods showed catalytic performance comparable to the catalysts prepared by impregnation.

Bridging the gap between insightful simplicity and successful complexity: From fundamental studies on model systems to technical catalysts

When Haldor Topsøe founded his company in 1940, the application of solid catalysts in industrial chemical processes was still in its early phase. At that time, catalyst development and optimization strongly relied on phenomenological approaches and experimental know-how, whereas little knowledge existed on the nature of the catalytically active species and how to tune their structure and concentration. For more than 70years, Topsøe has advocated the need of “bringing more scientific understanding to the field of catalysis,” becoming a prominent figure in the transition of catalyst preparation – a word with an alchemical connotation – to catalyst synthesis, based on scientific principles. Numerous fundamental studies of his team and collaborators on simplified model catalysts have added substantially to the current understanding of a significant number of industrially relevant systems in particular, and the principles of action of solid catalysts in general. This article reviews some key advancements that the Topsøe team has contributed to the field of catalyst development, rooted in fundamental studies with either 2D or 3D model materials. Examples are provided of how the acquired scientific knowledge was successfully translated into innovations in the manufacture of technical catalysts. Next to the work of the Topsøe group, a broader and updated perspective of the use of model systems to investigate fundamental aspects of catalyst development is presented. A number of selected case studies are reviewed, which we find illustrative of recent findings with implications for the design and synthesis of solid catalysts.

ChemInform Abstract: Mechanochemical Synthesis of Advanced Nanomaterials for Catalytic Applications

AbstractReview: [92 refs.

Synthesis of Solid Catalysts. Edited by Krijn P. de Jong

Wiley-VCH, Weinheim, 2009. 422 pp., hardcover, € 138.00.—ISBN 978-3-527-32040-0

Synthesis of Solid Catalysts. Edited by Krijn P. de Jong.

Wiley-VCH, Weinheim 2009. 402 pp., hardcover € 139.00.—ISBN 978-3527320400