Short CV
1. Academic Degrees BsC, Chemical Engineering, University of Coimbra, (1978). PhD, University of Sheffield, UK, (1983), "Diffusion Controlled Growth and Dissolution of Gas Bubbles". “Agregação”, University of Aveiro, (1995 2. Positions: Teaching assistant, Ceramics and Glass Eng. Dep., University of Aveiro (1978-1984) Assistant Professor, Ceramics and Glass Eng. Dep., University of Aveiro (1984-1988) Associate Professor, Ceramics and Glass Eng. Dep., University of Aveiro (1988-1996) Full Professor, Ceramics and Glass Eng. Dep., University of Aveiro (from 1996) 3. Other responsabilities Member of Directing Board, Centre of Ceramics and Glass,INIC, (1984-1993). Co-ordinator of Pedagogic Committee of Ceramics and Glass Engineering (1984-1986). Co-ordinator of the Departmental Scientific Commission (Ceramics and Glass Engineering) (1986-1989; 1999-2000). Secretary for the Inter-University MSc course on Material Engineering (1989-1991) Member of the Scientific Commission of the Inter-University MSc course on Material Engineering (1989-1990; 1992-5). Head of Department (1995-97) Secretary for the Institute of Postgraduation of the University of Aveiro (from 2000)
Scientific Interests
Main Research Areas 5.1 High temperature electrochemical applications Envisaged applications are solid oxide fuel cells, mixed conducting membranes for oxygen separation or partial oxidation of hydrocarbons, gas sensors, materials for high temperature electrolysis, oxygen pumping, etc. This involves research on electrolyte and electrode materials, their properties and performance, including the electrocatalytic activity, thermal and chemical compatibility between different cell materials. Laboratory scale devices are prepared for demonstration and teaching purposes. 5.1.1 Solid oxide fuel cell materials and concepts Solid electrolytes are studied with an emphasis on ceria-based materials for solid oxide fuel cells operating at lower temperatures. Additives are used to assist the sinterability, to obtain electrolytes with sub-micrometer grain sizes and to adjust the transport properties. Ionic conductors with different structure types are also studied (e.g. pyrochlores Gd2-xCaxTi2O7-d, and La2Mo2O9). Detailed studies are performed to assess their stability under severe working conditions, undue phase transformations, segregations, etc, using different methods (X-Ray diffraction data, electron microscopy, microanalysis and also electrochemical methods. A unique combination of electrical and electrochemical techniques is used to determine transport properties of different cell materials. Novel anodes materials are studied for intermediate-temperature solid oxide fuel cells (IT SOFCs) and as alternative anodes for direct conversion of hydrocarbons without previous reforming. One attempts to achieve improved characteristics such as electrocatalytic activity, microstructural stability, redox and sulphur tolerance. Actual anodes concepts include cermets, made of nickel or nickel-based alloys with different ceramic phases possessing oxygen ion conductivity (e.g. ceria or yttria-stabilized zirconia), protonic conductivity (e.g. alkaline earth cerates of zirconates), mixed conducting phases, electrocatalysts, etc. Suitable techniques are used to prepare anodes with uniform distribution of the cermet components. Structured anodes are prepared by a cellulose-precursor technique. Layered materials (e.g. La2Ni0.8Cu0.2O4+d are being studied as promising cathode materials with good mixed conduction, electrocatalytic activity and thermal expansion compatibility with the electrolyte materials. Suitable methods are being used to obtain nanocrystalline powders of these cathode materials. 5.1.2 Mixed conducting materials for oxygen separation or partial oxidation of hydrocarbons Dense ceramic membranes with mixed oxygen-ionic and electronic conductivity are of great interest for oxygen separation or conversion of methane or natural gas to synthesis gas (syngas). These membranes can also be used for oxygen separation, to obtain high purity oxygen. This research addresses the main requirement s of high oxygen permeability, the kinetics of surface exchange without and without catalysts, chemical stability under oxidising conditions, under reducing conditions and under large gradients of chemical potential, thermal stability. A large variety of materials and structure types are studied, including perovskites (e.g. LaGaO3-based materials, (Sr,La)CoO3.d, (Sr,La)FeO3.d, CaTi1-xFexO3-d,...), related layered phases (e.g. La2NiO4), brownmellerites, apatites, etc. Different routes are being used to prepare these materials, including attempts to obtain textured samples of layered materials in order to optimize the properties. Selected materials are tested in methane conversion conditions. Thermodynamic calculations and modelling are used to predict the working conditions and materials requirements (stability and transport properties) of mixed conducting membrane reactors for partial oxidation of methane combined with water vapour reforming. 5.1.3 Other electrochemical applications Research plans for the near future include other materials and cell concepts for alternative carbon-free fuels (e.g. ammonia), and alternative technologies to replace CO2-intensive industrial processes (e.g. steelmaking). This includes a participation in the ULCOS consortium, involving 48 partners from most west European countries. 5.2 Solid state reactions and related topics 5.2.1 Glass-ceramic materials Research activities are focused on mathematical modelling of glass crystallisation, mainly for non-isothermal conditions. One addresses the applicability of well known models and the effects exerted by time and temperature of nucleation. Some well known model systems (e.g. lithium disilicate) will be used to assess the correctness of those theoretical calculations and revised models. These models will also be used to re-examine the kinetics of crystallisation of promising bio-glass ceramics. Phase transformations in some solid electrolytes (e.g. La2Mo2O9) and other promising ceramic materials is a motivation for other kinetic studies, with an emphasis on revised models to interpret experiments performed under variable temperature, based on classical thermal analyses (DTA, TGA, DSC and dilatometry), and also on less common methods (e.g. transient changes in electrical behaviour).