Presenter: Ahmed Abdellah
Supervisor(s): Dr. Drew Higgins

Project Description: Recently, the electrochemical carbon dioxide reduction (CO2R) has attracted great attention as a promising method for CO2 conversion into beneficial fuels and chemical products. . Due to the large energy barrier of CO2R, the development of efficient catalysts is required. Understanding the mechanistic pathways and performance descriptors of CO2R will generate more opportunities to develop highly active catalysts. Herein, we focus on understanding the CO2R mechanisms and performance descriptors using in-situ transmission electron microscopy (TEM). For this purpose, Pd-based nanoparticles have been chosen because of their high affinity to convert CO2 into CO and formic acid. During the reaction and depending on the applied potential, Pd is going under phase transformation from pure-Pd phase to β-phase PdH. This β-phase was found to enhance the selectivity of CO2R toward the formation of formic acid. Therefore, investigating the reaction mechanism will be of great impact for that purpose. In this regard, in-situ TEM liquid cell has been modified to correctly fit with the CO2R reaction setup. Afterwards, Pd nanoparticles were prepared via electrodeposition using the same cell. Starting with TEM/STEM imaging, conducting Energy Dispersive X-Ray Analysis (EDX) mapping, and collecting selected area electron diffraction (SAED), we were able to determine three different phase transformation of Pd to PdH (α and β-phase) as a function of the applied potential. Afterwards, the same CO2 electro reaction using the same Pd-based catalyst has been conducted without TEM measurements ex-situ to quantify the formed products using gas chromatography (GC) and nuclear magnetic resonance (NMR) facilities. This aims to generate performance descriptors of Pd for the CO2R, which will positively influence the catalyst development orientation in this field.