Philip A. Barnes

Bio: Philip A. Barnes is an academic researcher from University of Huddersfield. The author has contributed to research in topics: Thermal analysis & Carbon. The author has an hindex of 15, co-authored 37 publications receiving 600 citations.

Reduction of Iron Oxide Catalysts: The Investigation of Kinetic Parameters Using Rate Perturbation and Linear Heating Thermoanalytical Techniques

Abstract: The mechanisms and kinetics of the reduction of powdered Fe2O3 and Fe3O4 samples have been investigated under nonisothermal conditions to provide a detailed insight into the processes occurring. Both conventional linear heating temperature-programmed reduction (TPR) and constant rate temperature-programmed reduction (CR-TPR) techniques were utilized. Fe2O3 was found to reduce to Fe in a two-step process via Fe3O4. The mechanism of the prereduction step of Fe2O3 to Fe3O4 was found to follow an nth order expression where nucleation or diffusion was not the rate-controlling factor while the main reduction step to metal was described by a model involving the random formation and growth of nuclei. A CR-TPR rate perturbation method, “rate-jump”, was applied to the measurement of variations in apparent activation energy throughout the reduction processes, under near-equilibrium conditions and the activation energy measurements are compared with those obtained under conventional linear heating conditions.

A new approach to the statistical optimisation of catalyst preparation

Abstract: The statistical design of experiments is not widely used due to the apparent complexity of the procedures involved. A simplified approach, based on the methods of Taguchi, is described and is illustrated by applying it to the optimisation of the preparation of a metal-carbon catalyst. The surface area was increased from 8 to 250 m 2 g −1 . It is shown that the method gives five significant advantages. It enables the amount of experimentation to be significantly reduced; it provides a means for assessing the significance of synergistic effects (interactions) between variables (factors) and it can yield evidence for the existence of previously unsuspected interactions. The method has the advantage of being applicable to existing production processes by assessing the consequences of variations in operating parameters found within normal run conditions. Finally, the experimental design process is simplified and the analysis of results is facilitated by the ready availability of the required statistical techniques in commercial software for microcomputers.

Energy storage applications of activated carbons: supercapacitors and hydrogen storage

Abstract: Porous carbons have several advantageous properties with respect to their use in energy applications that require constrained space such as in electrode materials for supercapacitors and as solid state hydrogen stores. The attractive properties of porous carbons include, ready abundance, chemical and thermal stability, ease of processability and low framework density. Activated carbons, which are perhaps the most explored class of porous carbons, have been traditionally employed as catalyst supports or adsorbents, but lately they are increasingly being used or find potential applications in the fabrication of supercapacitors and as hydrogen storage materials. This manuscript presents the state-of-the-art with respect to the preparation of activated carbons, with emphasis on the more interesting recent developments that allow better control or maximization of porosity, the use of cheap and readily available precursors and tailoring of morphology. This review will show that the renewed interest in the synthesis of activated carbons is matched by intensive investigations into their use in supercapacitors, where they remain the electrode materials of choice. We will also show that activated carbons have been extensively studied as hydrogen storage materials and remain a strong candidate in the search for porous materials that may enable the so-called Hydrogen Economy, wherein hydrogen is used as an energy carrier. The use of activated carbons as energy materials has in the recent past and is currently experiencing rapid growth, and this review aims to present the more significant advances.

Sorption of pollutants by porous carbon, carbon nanotubes and fullerene- An overview

Abstract: The quality of water is continuously deteriorating due to its increasing toxic threat to humans and the environment. It is imperative to perform treatment of wastewater in order to remove pollutants and to get good quality water. Carbon materials like porous carbon, carbon nanotubes and fullerene have been extensively used for advanced treatment of wastewaters. In recent years, carbon nanomaterials have become promising adsorbents for water treatment. This review attempts to compile relevant knowledge about the adsorption activities of porous carbon, carbon nanotubes and fullerene related to various organic and inorganic pollutants from aqueous solutions. A detailed description of the preparation and treatment methods of porous carbon, carbon nanotubes and fullerene along with relevant applications and regeneration is also included.

Activated carbon from lignocellulosics precursors: a review of the synthesis methods, characterization techniques and applications.

Abstract: Activated carbon is a porous material that has been in many important ages of the human history. Lignocellulosic precursors and biomass sources have become important materials to produce it because their use produces many benefits, mainly environmental. Nowadays, it is possible to find numerous research papers devoted to the synthesis characterization and applications of novel precursors to produce activated carbon. Hence, special attention must be given to the relationship among the selected precursor characteristics, the final microstructure and properties of carbon. The present work provides a summary of research works outlining the use of lignocellulosic–based precursors to obtain activated carbons. A brief description of the characterization techniques for both, the precursors and activated carbons, comprising: physicochemical, micro/nanostructural, surface chemistry, textural and adsorption capacity features is presented. Finally, the application of these materials in adsorption of heavy metals, dyes, volatile organic compounds, gas storage and electrochemical capacitors is also included.

Physical and chemical characterization of biochars derived from different agricultural residues

Abstract: . Biochar is widely recognized as an efficient tool for carbon sequestration and soil fertility. The understanding of its chemical and physical properties, which are strongly related to the type of the initial material used and pyrolysis conditions, is crucial to identify the most suitable application of biochar in soil. A selection of organic wastes with different characteristics (e.g., rice husk (RH), rice straw (RS), wood chips of apple tree (Malus pumila) (AB), and oak tree (Quercus serrata) (OB)) were pyrolyzed at different temperatures (400, 500, 600, 700, and 800 °C) in order to optimize the physicochemical properties of biochar as a soil amendment. Low-temperature pyrolysis produced high biochar yields; in contrast, high-temperature pyrolysis led to biochars with a high C content, large surface area, and high adsorption characteristics. Biochar obtained at 600 °C leads to a high recalcitrant character, whereas that obtained at 400 °C retains volatile and easily labile compounds. The biochar obtained from rice materials (RH and RS) showed a high yield and unique chemical properties because of the incorporation of silica elements into its chemical structure. The biochar obtained from wood materials (AB and OB) showed high carbon content and a high absorption character.