Design de novos catalisadores de cobalto Azul da Prússia aplicados na reação de oxidação da água: como a rota sintética afeta a performance?

Author(s)

Daniel Esteves Bessa Moreira

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Química
• Defense date: 2021-12-15

Examining board members

Juliano Alves Bonacin; Fernando Aparecido Sígoli; Daniel Grasseschi

• Advisor: Juliano Alves Bonacin

Abstract

Hydrogen gas (H2) has been calling attention of scientists once it is a renewable and carbon-free source of energy; besides, it has no harmful products after a typical combustion reaction. However, the majority of the H2 worldwide is produced by reforming methods, which use fossil fuels, and approximately 5% of hydrogen gas is produced by a process known as water splitting. This latter process is based on two half-reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Also known as water oxidation reaction, the OER process is the limiting step of OER, once it involves a transfer of four protons coupled with four electrons, which require very specific conditions to occur. In view of that, a catalyst is required to make the water oxidation occurs in considerable yields. Currently, Prussian Blue (PB) and its analogues (PBA), complexes in which transition metals ions (such as Fe, Co and Ni) are linked by cyanide bridges, have been drawing attention as water oxidation catalysts. In view of that, in the present work we study the behavior of Cobalt Prussian Blue (Co PBA) applied in the water oxidation reaction in neutral media. Therefore, different routes of synthesis were used to produce six Cobalt Prussian Blue Analogues, {Co}_3[Co({CN)}_6]2. It is worth to highlight that the morphology was a crucial point in this work. In this way, the routes were used to achieve different morphologies. In addition, to evaluate the electrocatalytic properties of all the synthesized materials, electrochemical parameters such as overpotential, tafel slope, oxygen production and turnover frequency (TOF), were determined aiming to study the properties of the materials, which were compared with materials previously reported in the literature. Finally, the present work aims to study the morphological influence of the cobalt Prussian Blue Analogue applied as water oxidation catalyst under mild conditions (neutral media) (AU)

• FAPESP's process: 19/20688-3 - Study of Prussian Blue analog nanowire properties for water oxidation
• Grantee: Daniel Esteves Bessa Moreira
• Support Opportunities: Scholarships in Brazil - Master