and Fuels Changzhi Li,† Xiaochen Zhao,† Aiqin Wang,† George W. Huber,†,‡ and Tao Zhang*,† †State Key Laborotary of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China ‡Department of Chemical and Biological Engineering, University of WisconsinMadison, Madison, Wisconsin 53706, United States

Catalytic Transformation of Lignin for the Production of Chemicals and Fuels

Spinels with the formula of AB2O4 (where A and B are metal ions) and the properties of magnetism, optics, electricity, and catalysis have taken significant roles in applications of data storage, biotechnology, electronics, laser, sensor, conversion reaction, and energy storage/conversion, which largely depend on their precise structures and compositions. In this review, various spinels with controlled preparations and their applications in oxygen reduction/evolution reaction (ORR/OER) and beyond are summarized. First, the composition and structure of spinels are introduced. Then, recent advances in the preparation of spinels with solid-, solution-, and vapor-phase methods are summarized, and new methods are particularly highlighted. The physicochemical characteristics of spinels such as their compositions, structures, morphologies, defects, and substrates have been rationally regulated through various approaches. This regulation can yield spinels with improved ORR/OER catalytic activities, which can furth...

Spinels: Controlled Preparation, Oxygen Reduction/Evolution Reaction Application, and Beyond

Catalysts for chemical and electrochemical reactions underpin many aspects of modern technology and industry, from energy storage and conversion to toxic emissions abatement to chemical and materials synthesis. This role necessitates the design of highly active, stable, yet earth-abundant heterogeneous catalysts. In this Review, we present the perovskite oxide family as a basis for developing such catalysts for (electro)chemical conversions spanning carbon, nitrogen, and oxygen chemistries. A framework for rationalizing activity trends and guiding perovskite oxide catalyst design is described, followed by illustrations of how a robust understanding of perovskite electronic structure provides fundamental insights into activity, stability, and mechanism in oxygen electrocatalysis. We conclude by outlining how these insights open experimental and computational opportunities to expand the compositional and chemical reaction space for next-generation perovskite catalysts.

http://science.sciencemag.org/content/sci/358/6364/751.full.pdf

Perovskites in catalysis and electrocatalysis

Polymer nanocomposites possess promising high performances as engineering materials, if they are prepared and fabricated properly. Some work has been recently done on such polymer nanocomposites as dielectrics and electrical insulation. This was reviewed in 2004 based on the literatures published up to 2003. New significant findings have been added since then. Furthermore, a multi-core model with the far-distance effect, which is closely related to an "interaction zones", has been proposed from consideration of mesoscopic analysis of electrical and chemical structures of an existing interface with finite thickness. It is speculatively examined in the paper how the model works for various properties and phenomena already found in nanocomposites as dielectrics focusing on electrical characteristics, resistance to high voltage environment, and thermal properties.

Dielectric nanocomposites with insulating properties

Polymer nanocomposites are defined as polymers in which small amounts of nanometer size fillers are homogeneously dispersed by only several weight percentages. Addition of just a few weight percent of the nanofillers has profound impact on the physical, chemical, mechanical and electrical properties of polymers. Such change is often favorable for engineering purpose. This nanocomposite technology has emerged from the field of engineering plastics, and potentially expanded its application to structural materials, coatings, and packaging to medical/biomedical products, and electronic and photonic devices. Recently these 'hi-tech' materials with excellent properties have begun to attract research people in the field of dielectrics and electrical insulation. Since new properties are brought about from the interactions of nanofillers with polymer matrices, mesoscopic properties are expected to come out, which would be interesting to both scientists and engineers. Improved characteristics are. expected as dielectrics and electrical insulation. Several interesting results to indicate the foreseeable future have been revealed, some of which are described on materials and processing in the paper together with basic concepts and future direction.

Polymer nanocomposites as dielectrics and electrical insulation-perspectives for processing technologies, material characterization and future applications

The invention relates to a grain refining agent for cast magnesium products, comprising particles formed of a matrix of a ductile material, in which are uniformly dispersed nucleation particles of at least one element or compound selected from the group consisting of zirconium, silicon carbide, titanium carbide and mixtures of carbon with silicon or titanium, the nucleation particles having an average particle size of 0.05 to 5 µm. The dispersion of the nucleation particles within a matrix of ductile material improves their wettability, overcomes problems caused by gas adsorption on the surface of the particles and reduces their agglomeration during inoculation into molten magnesium or alloy thereof.

Grain refining agent for cast magnesium products

New insight on the restructuring and breakage of particles during uniaxial confined compression tests on aggregates of petroleum coke

Coal-tar-pitch (CTP) is a fossil carbon material, currently used as a the binder in carbon anode manufacturing process. Regardless of the technical benefits of coal-tar-pitch, it contains polycycli...

Synthesis and Characterization of Bio-pitch from Bio-oil

The current study investigates the effects of coke particle characteristics and paste formulation on the flowability and the compression behavior of anode pastes. Shape factor and texture of different fractions of cokes were characterized using an image analysis system where the characteristics of each coke were correlated to its vibrated bulk density (VBD). A compression test was designed to study the effects of particle characteristics and paste recipe on the compactability of pastes. The test was applied on four anode pastes, prepared from different coke types, particle size distributions and pitch contents. It was observed that the compression test is significantly sensitive to any changes in raw materials characteristics and formulations. Consequently, the compression test may be used as a tool for evaluating anode quality in relation with material variations.

Effects of Physical Properties of Anode Raw Materials on the Paste Compaction Behavior

Carbon anode, used in the Hall-Heroult process, is subject to both air oxidation and carboxy gasification by CO2. These reactions are considered as being the main causes of dusting phenomenon in the electrolysis bath. More precisely, it is believed that CO2 and O2 preferentially attack the baked pitch (pitch coke) resulting in detachment of coke and butt particles in the form of dust. The present work aims at elucidating this phenomenon by studying the air and CO2 reactivities of the prebaked carbon anode and also of its constituents. The air and CO2 reactivities were evaluated using thermo-gravimetric analysis and the standard reactivity test of R&D Carbon, ISO Standard 12981-1. The microstructural features of the samples, i.e. real density, crystallite size and specific surface area, were measured. The reactivity of the anode and its constituents was assessed separately and their effect on dusting phenomenon was discussed.

Houshang Alamdari

Papers

Grain refining agent for cast magnesium products

New insight on the restructuring and breakage of particles during uniaxial confined compression tests on aggregates of petroleum coke

Synthesis and Characterization of Bio-pitch from Bio-oil

Effects of Physical Properties of Anode Raw Materials on the Paste Compaction Behavior

Air and CO2 Reactivity of Carbon Anode and Its Constituents: An Attempt to Understand Dusting Phenomenon