Banca de QUALIFICAÇÃO: JOHNATAN DE OLIVEIRA SOARES

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JOHNATAN DE OLIVEIRA SOARES
DATE: 27/08/2026
TIME: 08:30
LOCAL: Auditorio do IQ 3
TITLE:

Oxidative Dehydrogenation of Ethylbenzene to Styrene Using Carbonaceous Materials

KEY WORDS:

Chitosan; Biochar; Oxidative dehydrogenation; Ethylbenzene; Styrene.

PAGES: 134
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Cinética Química e Catálise
SUMMARY:

The oxidative dehydrogenation (ODH) of ethylbenzene using carbonaceous materials has attracted growing interest due to their high
conversion, selectivity, and lower environmental impact compared to conventional metal-based catalysts. In this context, this work investigated
the synthesis, characterization, and application of biochars derived from chitosan as heterogeneous catalysts for oxidative dehydrogenation
reactions, correlating their structural and chemical properties with catalytic performance. The biochars were obtained through thermochemical

carbonization of chitosan at different temperatures under a N2 atmosphere, as well as via a hybrid bead method for the preparation of metal-
doped biochars. The results showed that the synthesized materials exhibited high surface heterogeneity, developed porous structures, and

significant incorporation of oxygen- and nitrogen-containing functional groups on the carbon surface. Spectroscopic analyses indicated the
presence of conjugated aromatic structures and structural defects associated with nitrogen doping, while CO2-TPD measurements revealed
basic sites of different strengths related to surface functionalities formed during carbonization. In the catalytic tests for ethylbenzene ODH, the
biochars showed distinct performances depending on the carbonization temperature, with conversions ranging from 49.30 to 78.42% and
styrene yields between 26.12 and 78.42%. The CQT600 sample exhibited the best performance, reaching 78.42% conversion and an
equivalent styrene yield. It was observed that increasing surface area and carbonization temperature significantly enhanced catalytic activity,
particularly for CQT600, which showed a surface area of 652 m2/g and the highest specific activity. The presence of CO2 also influenced
adsorption and molecular activation mechanisms on the biochar surface, contributing to a better understanding of the catalytic nature of these
carbon-based materials.

COMMITTEE MEMBERS:
Presidente - 2087667 - TIAGO PINHEIRO BRAGA
Interno - 350509 - ANTONIO SOUZA DE ARAUJO
Externo à Instituição - FELIPE FERNANDES BARBOSA - UFRN