Chemometric evaluation of Ni/CeO2 catalysts in the CO2 reduction reaction obtained by coprecipitation: an operando study

• Grant number: 23/04143-2
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): June 01, 2023
• Effective date (End): October 31, 2027
• Field of knowledge: Engineering - Chemical Engineering - Chemical Technology
• Principal Investigator: Luiz Gustavo Possato
• Grantee: Matheus Silva de Assis
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil
• Associated research grant: 21/05246-4 - In situ and operando studies of heterogeneous catalysts for CO2 conversion, AP.JP

Abstract

The transition metals of groups 8, 9 and 10, i.e. nickel, ruthenium, palladium, rhodium, platinum, copper, molybdenum, rhenium, silver, gold, iron and cobalt, are active for the carbon dioxide methanation reaction and given that Ni is much more widely available as well as cheaper than noble metals, most research on CO2 methanation is now focused on Ni-based catalysts. Of the transition metal-based catalysts studied, Rh and Ni showed the best catalytic performance. However, the price of Rh is 500 times higher than that of Ni. CeO2-supported metal catalysts exhibit a number of interesting structure and surface features, including the Ce4+/Ce3+ redox couple, surface defects, metal-support interface, etc., which have been identified as catalytic active sites in many chemical reactions. . The catalytic properties and capacity in terms of activation of reagents, the transformation of intermediates and the final catalytic activity/selectivity/stability can be effectively tuned by adapting the previously mentioned properties associated with the domain of ceria (e.g. morphology, oxygen vacancies on surface and functionality) and supported metal phase (e.g. particle size, composition and electronic structure). The new line of research in catalysis will be supported by a multi-user network of chemical synthesis and manipulation laboratories: a VERTEX 70 Infra-Red Region Spectrometer (IRFT) with accessories, for the analysis of surfaces and thin films A513Q Angle Reflection Advice variable; a Leica DCM 3D Confocal Microscope with anti-vibration table; of a SHIMADZU SPM-9700 Atomic Force Microscope (Scanning Probe Microscope with anti-vibration table; of a Rigaku D/MAX-2100 Diffractometer; a Gas Chromatograph with Flame Ionization Detector (FID) and Pulsing Flame Photometer Detector (PFP), with automatic injector and electronic flow control (CG-FID) (01 unit); a high performance liquid chromatograph with diode array detector (HPLC-DAD); a high performance liquid chromatograph with detector (HPLCFL); a High Performance Liquid Chromatograph with Conductivity Detector (HPLCCD); an Ultraviolet/Visible Spectrophotometer (UV-Vis), Potentiostats and Electrochemical Impedance (IES) and a Carl Zeiss Scanning Electron Microscope Model EVO/LS15 with microprobe (EDS). Experimentation and statistical analysis are extremely important procedures for the use of chemometric tools, with the aim of optimizing a chemical experiment. In most situations, whether it is the improvement of products, processes or chemical experiments, the result depends on several parameters/factors. A test for evaluation necessarily requires several parameters to be tested simultaneously.Statistical tools for experimental design seek to reduce the number of experimental tests, allowing the simultaneous study of the evaluation of several variables in a catalytic process. The factorial experimental design is a very useful data analysis tool, and its main application lies in the evaluation of the most relevant process variables of a chemical experiment. After evaluating the variables that represent the greatest significance for the process, experiments are performed that allow optimizing the results of interest.The key concept of the operating methodology is to simultaneously obtain reliable structure and catalytic data, making it possible to evaluate structure-activity relationships. Therefore, a spectroscopic operating cell has to be a catalytic reactor meeting the necessary design specifications, such as (1) no mass or energy transfer limitations and (2) no bypass or back mixing, for example, characterized by dead volume. (AU)