Diffusion mechanism of platinum nanoclusters on well-aligned carbon nanotubes

Abstract

Carbon supported platinum (Pt/C) remains among the preferred catalyst materials for use in proton exchange membrane fuel cells; however, its durability must be improved.

Hydrogen Evolution at the Buried Interface between Pt Thin Films and Silicon Oxide Nanomembranes

“…To date, efforts to improve the stability of nanoparticle electrocatalysts in fuel cells and electrolyzers have focused on modifying the electrocatalyst itself or the support material to which the nanoparticles are adhered. For example, Adzic et al have shown that the durability of low-dimensional Pt ORR catalysts can be significantly enhanced by utilizing core–shell structures whereby the strong interaction between the Pt and Au core imparts enhanced stability to the Pt. , Other research groups have demonstrated improved stability by modifying the carbon support − or by using alternate support materials such as transition-metal carbides , and conductive metal oxides . The current article is motivated by a different approach to enhance electrocatalyst stability that is based on encapsulating the active electrocatalyst material by an ultrathin, permeable overlayer that can prevent the previously mentioned degradation mechanisms while simultaneously allowing transport of reactants and products between the electrolyte and the surface of the active electrocatalyst. − Similar structures such as core–shell nanoparticles have previously enhanced thermal stability for high-temperature heterogeneous catalysis − and have been used to suppress undesired back-reactions in photoelectrochemical applications. − Several studies have also demonstrated the benefits of using ultrathin oxide layers for stabilizing metallic nanoparticles or molecular catalysts in low-temperature fuel cells ,− and photoelectrochemical cells, , including studies by our laboratory .…”

Low-temperature atomic layer deposition delivers more active and stable Pt-based catalysts

“…[28][29][30][31][32] The graphene nanoplatelets were chosen because they are a promising support for catalytic applications. [33][34][35][36] Moreover, Pt adatoms and nanoparticles tend to migrate and sinter more readily on graphene than on other supports, [37][38][39][40] such that our system can be considered especially challenging in this respect. Finally, we show that our method, by producing bulk quantities of supported-NPs with narrow size distributions, is also an excellent tool for studying the sizedependent catalytic properties of supported noble-metal NPs.…”

Atomistic investigation on the diffusion mechanism of Pt nanoclusters on well-aligned multi-walled carbon nanotubes

“…3; it is the reason that the Pt cluster in the trench can experience the vdW interaction forces from two adjacent CNTs, which may be larger than those coming from single CNT. In our previous work [38], the investigation of Pt cluster deposited on well-aligned SWCNTs shows that the adsorption energy is basically obtained at the ratio d Pt (the Pt-cluster diameter) to d (CNT diameter) ranging from 0.6 to 0.8 with uniform spacing at a certain value. For example, for the Pt clusters with a d Pt of 1.2 nm (Pt 1.2 ), the WACNTs will be with a d of 1.9 and d w of 0.322 nm, and Pt clusters with a d Pt of 2.4 nm (Pt 2.4 ) correspond to WACNTs with a d of 3.3 nm and d w of 1.26 nm.…”