Insight on Thermally Activated Hydrocarbon Dehydrogenation on the Pt₃Ni(111) Surface: From Adsorbed Hydrocarbons up to Graphene Formation

Abstract

The Pt 3 Ni(111) alloy is characterized by the presence of an outermost surface layer only composed by Pt atoms, that is, the so-called Pt skin, which is at the basis of its outstanding performances in oxygen reduction reaction. The growth of graphene on this alloy is further motivated by the realization of a charge-neutral Gr/metal gate, which can be replaced by a p-doped Gr/oxide/metal configuration upon heating in an oxygen environment. Herein, we have followed the complete reaction pathway starting with adsorbed hydrocarbons and ending with the large-scale growth of a graphene overlayer. Experiments using temperatureprogrammed X-ray photoelectron spectroscopy have been carried out for different conditions (C 2 H 4 dose and sample temperature). Submonolayer graphene (0.08 ML) is reached upon heating at T = 1000 K an ethene monolayer dosed at T = 80 K. Conversely, monolayer graphene domains are achieved for C 2 H 4 cracking at T = 800 K. We also find that carbon atoms dissolved into the bulk segregate toward the substrate during the cooling.

Aligning time-resolved kinetics (TAP) and surface spectroscopy (AP-XPS) for a more comprehensive understanding of ALD-derived 2D and 3D model catalysts

“…The concept of correlating AP-XPS data to the kinetics of carbon growth on the exposure scale has been successfully exploited in the context of graphene growth on model materials. 16,17,50 In comparison, our work introduces this concept to the eld of the precise kinetic characterization of catalytic reactions. To fully appreciate the possibilities entailed by a fully quantitative data alignment, it should be emphasized that TAP offers a detailed view of reaction kinetics at several temporal scalesfrom sub-second differences in the mean residence times of species, through several seconds within each pulse, to the accumulated changes over hundreds of pulsesand all these characteristics could be related to the surfacesensitive spectral features probed by XPS for cases of technological and fundamental importance.…”

“…[41][42][43][44][45][46][47][48] More recently, an ALD-derived PtIn catalyst was reported that achieved unprecedented catalytic performance by combining propane dehydrogenation with selective hydrogen combustion. 49 Although time-resolved XPS studies have been extensively reported for similar (single crystal) model materials, 16,17,50 our ndings provide the rst example in which AP-XPS and TAP data were evaluated on nanoscopically-equivalent, triplecomponent (Pt, In, and MgO) ALD model materials.…”

Surface Engineering of Substrates for Chemical Vapor Deposition Growth of Graphene and Applications in Electronic and Spintronic Devices

“…Moreover, when the grown graphene was heated in an oxygen environment, Ni atoms segregated toward the surface followed by being oxidized to an oxide layer containing Ni . This process converted the graphene/metal configuration to the graphene/metal oxide/metal configuration, which might have important significance in the field of electronic devices. , In brief, the dual-element alloy single-crystal plane can not only keep the orientation of graphene growth but also achieve the layer number control by adjusting the atomic ratios of different metals in the alloy. Owing to the unique dual-element and single-crystal plane characteristics of the single-crystal binary alloys, those alloys have great potential in the preparation of graphene.…”