Atomic Layer Deposition of Pt on Tungsten Monocarbide (WC) for the Oxygen Reduction Reaction

Abstract

Atomic layer deposition (ALD) was utilized as a synthesis method to deposit monolayers of Pt onto WC substrates for applications as oxygen reduction reaction electrocatalysts. Samples utilizing various Pt ALD cycles were characterized using surface analytical methods and scanning electron microscopy, whereas cyclic voltammetry was used to determine whether the oxygen reduction reaction takes place on the catalyst surface. ALD Pt was found to deposit onto WC substrates following an island growth mechanism. When few Pt ALD cycles are used, discrete Pt particles first formed and dispersed over the WC substrate, but at least 100 ALD cycles is required for the WC substrate to be covered with Pt. Whereas Pt monolayers are not obtained, ALD Pt on WC still shows activity for the oxygen reduction reaction. Cyclic voltammetry conducted in an O 2 -saturated 0.5 M H 2 SO 4 electrolyte indicate that as few as 20 Pt ALD cycles on WC is needed to produce oxygen reduction reaction activity that is comparable to Pt bulk. Efforts to make Pt films that are even thinner and more monolayer-like are desired, and potential approaches are discussed.

An atomic layer deposition reactor with dose quantification for precursor adsorption and reactivity studies

“…26 Relatively few diagnostics have been applied to explicitly look at the time dependence of the gas-phase reactant, as it relates to the surface reactions, with the notable exception of recent IR techniques. [27][28][29] QMS techniques have been applied to ALD for some time, [30][31][32] but generally qualitatively to look only at the presence of particular species in the gas phase, for understanding reaction mechanisms, rather than to probe actual reactant exposure dynamics.…”

A Co2P/WC Nano‐Heterojunction Covered with N‐Doped Carbon as Highly Efficient Electrocatalyst for Hydrogen Evolution Reaction

“…[3][4][5] Pt-basedc atalysts perform well in the HER; however, because of the high cost and lowa bundance of Pt metal on earth, variousn onprecious-metal-based electrocatalysts have been designed to tackle these problems. [39][40][41][42][43][44][45] Nano-heterojunctions, which combine the advantages of nanomaterials and heterojunctions, have recently been employeda sanew type of electrocatalyst because of their unique physicochemical properties. Among them, transition-metal phosphides,e specially Co 2 P, have attracted considerable attention.…”

“…[37,38] The combination of two or more catalyticallya ctive components to form ac omposite catalysts has received much attention. [39][40][41][42][43][44][45] Nano-heterojunctions, which combine the advantages of nanomaterials and heterojunctions, have recently been employeda sanew type of electrocatalyst because of their unique physicochemical properties. [46][47][48][49][50] It is well knownt hat transition metal carbides (e.g.,W C, MoC) possess aP t-like d-band electronic structure, which endows them with suitable capacity for H ads release.…”

Atomic layer deposition of high-density Pt nanodots on Al2O3 film using (MeCp)Pt(Me)3 and O2 precursors for nonvolatile memory applications

“…In recent years, atomic layer deposition (ALD) of Pt nanoparticles have been investigated on various surfaces such as micron-sized porous silica gel particles [10], SrTiO 3 nanocubes [11], WC [12], and SiO 2 film [7]. However, most of them are used for catalyst.…”