Preparation of PtNi@SDC core-shell nanoparticles by conventional preformed-core method

• Main Author: Yong, Hui Yi
• Other Authors: Su Pei-Chen
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/150130
• Institution: Nanyang Technological University

Platinum-Nickel (PtNi) core nanoparticles were prepared via solvothermal synthesis across solvothermal times of 6, 12, 18 and 24 hours, and 10, 50, 100 and 150mM of Hexadecyltrimethylammonium bromide (CTAB) concentrations. The PtNi nanoparticles generally increase in size as the CTAB concentration increases. The PtNi nanoparticle size at low CTAB concentration is smaller than that at high CTAB concentration, which is attributed to the poor and the better stabilisation of CTAB at low and high CTAB concentrations respectively. In addition, the PtNi nanoparticles were observed to grow larger as the solvothermal time increases as there was more time for the growth process to occur. All the prepared PtNi nanoparticles were subjected to thermal annealing at 450°C, 600°C and 800°C, and nanoparticles synthesised at 18 and 24 hours, with 50mM, 100mM and 150mM of CTAB concentrations were found to have survived the thermal annealing without agglomeration. The large particle size of these nanoparticles contributed to its high thermal stability, despite deviating from the ideal composition of 1:1 Pt to Ni ratio. Also, the morphology of the PtNi nanoparticles fabricated at 50mM of CTAB concentration at 18 hours of solvothermal time was preserved, which displayed the highest thermostability. The polarisation study conducted on the PtNi nanoparticles synthesised under such conditions achieved a maximum power density of 0.124mW/cm2. In order to fabricate the core-shell nanostructure of the Platinum-Nickel core and Samarium-Doped Ceria shell (PtNi@SDC), the Samarium-Doped Ceria (SDC) shell nanoparticles were synthesised via hydrothermal at of 90°C, 120°C and 160°C with the hydrothermal time of 18 hours. However, results showed that discrete Cerium (IV) oxide and PtNi nanoparticles were obtained instead of PtNi@SDC. Thus, it was concluded that PtNi@SDC nanoparticles could not be produced via hydrothermal synthesis due to the high polarity of water, which caused the SDC particles to separately form its oxide instead of being 4 deposited on the PtNi nanoparticles. Future research could focus on the fabrication of the PtNi@SDC nanoparticles using a different solvent or method and subsequently analyse the performance of the PtNi@SDC cathode material via a polarisation test.