Sintering Rate and Mechanism of Supported Pt Nanoparticles by Multiscale Simulation

Abstract

Thermal stability is the key issue in the industrial application of supported metal nanocatalysts. A combination method of density functional theory calculations, machine learning, and molecular dynamics simulation is adopted to study the sintering behavior of supported platinum (Pt) nanoparticles on graphene or TiO 2 nanosheet, and analyze sintering mechanisms under different temperatures, particle sizes, and metal support interactions (MSIs). The results show that the agglomeration of supported nanoparticles is mainly based on the mechanism of small particle migration and growth. Small-sized particles with high surface energy determine the sintering rate. In addition, the increase of temperature is conducive to the agglomeration of particles, especially for systems with strong MSI. Based on the analysis of the sintering process, a sintering kinetic model of supported Pt nanoparticles related to particle size, temperature, and MSI is established, which provides theoretical guidance for the design of supported metal catalysts with high thermal stability.

Sintering Kinetics and Interfacial Heat Transfer Process of Binary Alloy Nanoparticles Catalysts: Molecular Dynamics Simulation

“…This distance can effectively demonstrate the particle sintering behavior at different temperatures in the current system. 37 The time step is also 1 fs, simulating 500 ps under the NVT ensemble at 300 K. Subsequently, rapidly increase the temperature to the specified value (within 100 ps) just before the upcoming sintering process simulation. During the sintering stage, employ the NVE ensemble, and observe the sintering state of the particles.…”

Design Strategies of Stable Catalysts for Propane Dehydrogenation to Propylene

“…Besides, several types of supports have been explored, among which oxide supports (Al 2 O 3 , SiO 2 , and TiO 2 and zeolites have been widely applied. Some catalysts with high catalytic activity often suffer from rapid deactivation and poor regeneration ability on account of coke accumulation and/or sintering of active compounds under the high temperature required in the reaction and regeneration processes. − Coke deposition can occur on both the active compounds and th esupport surface, ultimately leading to catalytic deactivation by impeding mass transfer and poisoning the active sites. Sintering is a process where the supported active compounds agglomerate via a particle migration and coalescence process or the Ostwald ripening process into bigger particles. , Coke formation, coupled with the sintering behavior, is usually inevitable, resulting in an inexorable catalytic deactivation.…”

An Atomistic View of Platinum Cluster Growth on Pristine and Defective Graphene Supports

“…[11][12][13] In addition, dissolution processes during catalytic reactions and due to interactions with the electrolyte can lead to material loss. [11,[14][15][16][17] Recent studies have shown that while TM NPs bind weakly to pristine graphene, defect sites in graphene can serve as anchor points that greatly increase binding strength. Interestingly, this anchoring effect is prominent in particular for small TM clusters, which can fit into defects that are only several atoms wide where they covalently bind to the unsaturated carbon atoms.…”

“…[ 11–13 ] In addition, dissolution processes during catalytic reactions and due to interactions with the electrolyte can lead to material loss. [ 11,14–17 ]…”