Effect of Precursor Status on the Transition from Complex to Carbon Shell in a Platinum Core–Carbon Shell Catalyst

Abstract

Encapsulating platinum nanoparticles with a carbon shell can increase the stability of core platinum nanoparticles by preventing their dissolution and agglomeration. In this study, the synthesis mechanism of a platinum core–carbon shell catalyst via thermal reduction of a platinum–aniline complex was investigated to determine how the carbon shell forms and identify the key factor determining the properties of the Pt core–carbon shell catalyst. Three catalysts originating from the complexes with different platinum to carbon precursor ratios were synthesized through pyrolysis. Their structural characteristics were examined using various analysis techniques, and their electrochemical activity and stability were evaluated through half-cell and unit-cell tests. The relationship between the nitrogen to platinum ratio and structural characteristics was revealed, and the effects on the electrochemical activity and stability were discussed. The ratio of the carbon precursor to platinum was the decisive factor determining the properties of the platinum core–carbon shell catalyst.

Effect of Heat Treatment on Structure of Carbon Shell-Encapsulated Pt Nanoparticles for Fuel Cells

“…However, the decomposition of the carbonaceous gas and the formation of the carbon shell are too slow to avoid the increased size of the metal nanoparticles during the high-temperature annealing process, leading to the reduced electrochemically active surface area (ECSA) [ 24 , 25 , 26 ]. In contrast, the bulky structure of polymers makes it difficult to effectively regulate the pore structure and thickness of the carbon layer during the polymer coating/graphitization process [ 27 ]. Hence, to circumvent the above-mentioned drawbacks of the processes, more effective approaches that allow for the fine control of the structure of carbon shell-encapsulated metal nanoparticles should be developed.…”

Origin and Formation Mechanism of Carbon Shell-Encapsulated Metal Nanoparticles for Powerful Fuel Cell Durability

“…Well-controlled carbon shells are the key to inhibiting structural deformation while maintaining both activity and durability. Thus, the precursor ligand-induced method holds a distinct advantage in this regard [21][22][23][24][25][26][27]. Despite this, the origin and formation mechanism of carbon shell formation through these precursor-based methods have not been clearly elucidated yet.…”