Enhancing of catalytic properties of vanadia via surface doping with phosphorus using atomic layer deposition

Abstract

Atomic layer deposition is mainly used to deposit thin films on flat substrates. Here, the authors deposit a submonolayer of phosphorus on V₂O₅ in the form of catalyst powder. The goal is to prepare a model catalyst related to the vanadyl pyrophosphate catalyst (VO)₂P₂O₇ industrially used for the oxidation of n-butane to maleic anhydride. The oxidation state of vanadium in vanadyl pyrophosphate is 4+. In literature, it was shown that the surface of vanadyl pyrophosphate contains V⁵⁺ and is enriched in phosphorus under reaction conditions. On account of this, V₂O₅ with the oxidation state of 5+ for vanadium partially covered with phosphorus can be regarded as a suitable model catalyst. The catalytic performance of the model catalyst prepared via atomic layer deposition was measured and compared to the performance of catalysts prepared via incipient wetness impregnation and the original V₂O₅ substrate. It could be clearly shown that the dedicated deposition of phosphorus by atomic layer deposition enhances the catalytic performance of V₂O₅ by suppression of total oxidationreactions, thereby increasing the selectivity to maleic anhydride

How to control selectivity in alkane oxidation?

“…We postulate that efficient catalysts for lower alkane activation might be found based on nano-structuring of crystalline materials that have shown so far no catalytic activity in their macro-structural appearance. Hydrothermal synthesis51,88,89 or atomic layer deposition90 might be a promising synthetic tool in this respect. Another descriptor might be the surface lattice oxygen bonding energy that has an impact on the mechanism of catalyst regeneration and the abundance of highly reactive electrophilic intermediates on the surface of the catalyst under reaction conditions that over-oxidize desired products including olefins and oxygenates to carbon oxides.…”

Design of PtZn nanoalloy catalysts for propane dehydrogenation through interface tailoring via atomic layer deposition

“…The potential of ALD has been widely investigated for catalyst development in the last two decades. 30 ALD can be used to stabilize nanoparticles via physical overcoating with an inert oxide layer, 31,32 formation of metallic / core-shell nanoparticles, 33 deposition of promoters on bulk catalysts, 34 and coating of powders with functional materials. 35 Here, we use ALD to tailor the interface between Pt nanoparticles and the SiO 2 used as support.…”

Investigating the Trimethylaluminium/Water ALD Process on Mesoporous Silica by In Situ Gravimetric Monitoring

“…However, porous materials can feature undesirable surface properties and a precise surface modification or functionalization is required for further application [2]. Especially in heterogeneous catalysis, surface deposits in a submonolayer regime can act as active sites or promoters [3,4]. In consequence, surface coating techniques for porous structures with high uniformity and control over the elemental composition, thickness, and morphology need to be developed.…”