Description
Liquid cell TEM (LC-TEM) allows to observe in situ dynamic processes occurring during reactions in liquid inside the TEM. Using LC-TEM technique, most important stages of growth dynamics dependence on the ion concentration, the initialization of growth sites or particle synthesis in liquid can be investigated. Synthesis and dissolving of Ce2O NPs and electrochemical properties of this binary catalyst (Ce2O@Pd NPs/C) were studied.
Dynamic processes were observed in real-time using LC-TEM. The electrochemical activity of the Ce2O@Pd NPs/C catalyst towards ethanol oxidation reaction (EOR) was evaluated. In-situ FTIR measurements were used to establish the catalytic activity and stability of Ce2O@Pd NPs. X-ray absorption near edge structure (XANES) and X-ray diffraction (XRD) were used to determine the oxidation state of Ce2O before and after ethanol oxidation reaction.
The LC-TEM experiment showed, that depending on the beam energy, the Ce2O NPs were synthesized or dissolved. The electrochemical results showed, that the presence of Ce2O NPs as a substrate for Pd NPs enhances the EOR. XANES and XRD measurements proved, that the synthesized Ce2O NPs were stable even after EOR and it was composed of two phases.
Using LC-TEM, synthesis, dissolution and decoration of Ce2O by Pd NPs was observed. The combination of XANES and XRD measurements gave detailed information about the structure of Ce2O NPs and changes of this structure caused by EOR reaction. Finally, the presence of Pd NPs on the Ce2O/C catalyst leads enhancement of the EOR.
Funding: This research was founded by the grant from the National Science Foundation 2019/35/B/ST5/04140.
