Banca de QUALIFICAÇÃO: BARBARA STEFANY LIMA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : BARBARA STEFANY LIMA DA SILVA
DATE: 13/02/2023
LOCAL: ambiente virtual, plataforma google meet
TITLE:

CATALYSTS BASED ON METALORGANIC FRAMEWORKS OF MANGANESE AND MANGANESE/COBALT FOR THE PRODUCTION OF HYDROGEN BY HYDROLYSIS OF SODIUM BOROHYDRIDE

KEY WORDS:

Metal-Organic Frameworks; Mn-BDC; MnCo-BDC; catalysis; Hydrogen; Sodium borohydride.

PAGES: 60
BIG AREA: Engenharias
AREA: Engenharia Aeroespacial
SUMMARY:

The fuels used in the aerospace industry are currently fossil-based petroleum raw materials. The fuel that can be used in the aviation industry must have a combination of different properties, such as high energy density, excellent burning characteristics, low viscosity, and low impact on the environment. For this reason, hydrogen has great potential to be used as an energy source for this application. However, there are major problems regarding the transport and storage of hydrogen. Aiming at this, the chemical storage of hydrogen in the form of simple compounds and their release on demand, stands out as a safe and promising alternative for the use of hydrogen as fuel. For the efficient release of hydrogen via hydrolysis of chemical compounds, such as sodium borohydride, the use of a catalyst is essential. In this work, two heterogeneous catalysts based on monometallic Mn-BDC and bimetallic Mn/Co-BDC Metal-Organic Frameworks were used. These materials were tested as catalysts in the production of hydrogen via NaBH₄ dehydrogenation, using the gas volume measurement system released by the water displacement method. The efficiency of the process was evaluated by varying the reaction temperature and NaOH concentration. The presence of cobalt in the structure resulted in better catalytic performance of the bimetallic MnCo-BDC framework compared to the monometallic Mn-BDC structure (HGR hydrogen production rate = 297 mL min^-1 g cat^-1 vs. 41.25 mL min ^-1 g cat^-1, for MnCo-BDC and Mn-BDC, respectively). The bimetallic catalyst also provided lower activation energy for the NaBH₄ hydrolysis reaction. The temperature had a positive impact on the catalytic activity for both samples.

The addition of NaOH to the system, despite not modifying the general efficiency of the reaction, led to a significant increase in HGR (231%). The most promising catalyst, MnCo-BDC, was evaluated in terms of useful life, showing the same hydrogen generation efficiency after 5 cycles, and low reduction in the HGR value, being a promising catalyst for hydrogen generation via NaBH₄ hydrolysis.

COMMITTEE MEMBERS:
Presidente - 2163324 - JOANNA ELZBIETA KULESZA
Interno - 1754300 - BRAULIO SILVA BARROS
Interno - 1810494 - KLEBER GONCALVES BEZERRA ALVES