Avaliação de catalisadores de níquel suportados em alumina sintetizados via magnetron sputtering para a produção de hidrogênio a partir da decomposição de metano

Abstract

Methane decomposition for hydrogen production is classified as blue turquoise, an intermediate between green and blue hydrogen. It does not generate greenhouse gas (GHG) emissions and does not require installation of carbon capture, utilization, and storage (CCUS) processes, becoming environmentally competitive among technologies, as the byproduct are solid carbon and hydrogen. In this regard, this research related to the topic was defined in two stages. The first stage was related to developing a methodology for evaluating a commercial catalyst (CC) for methane conversion in the methane decomposition reaction. The second one is related to the synthesis of catalysts by the magnetron sputtering technique, and the evaluation of the synthesized catalysts (CS) for methane conversion in its decomposition reaction. The first stage of the research contributes to optimizing temperature and space velocity parameters in methane conversion, adopting the concept of experimental design to collect data and identify significant factors through a complete 3² factorial design. Highest methane conversion, considering thermodynamic equilibrium limit of reaction, was obtained at 900 K and 6000 mL.h-1.g-1. The CC used was characterized by field emission scanning electron microscopy (FE-SEM), X-ray fluorescence (XRF), textural analyses (BET/DFT), and X-ray diffraction (XRD). In the second stage, Ni catalysts supported on alumina (y-Al2O3) were synthesized via the magnetron sputtering technique. Different deposition powers, deposition durations, and y-Al2O3 particle sizes were used for the synthesis of the catalysts. The synthesized catalysts (CS) achieved different Ni contents and were evaluated for methane conversion in the methane decomposition reaction. The synthesized catalysts (CS) were characterized by field emission scanning electron microscopy (FE-SEM), X-ray fluorescence (XRF), textural analyses (BET/DFT), and X-ray diffraction (XRD). The experiments demonstrated that the best results of the synthesized catalysts (CS) and the commercial catalysts (CC) used in this research are equivalent, approximately 80% methane conversion. However, nickel content of the synthesized catalysts (CS) is approximately 50% lower, suggesting a higher efficiency of the active metal. [resumo fornecido pelo autor]