Tuning catalysis by surface-deposition of elements on oxidation catalysts via atomic layer deposition

Abstract

Based on the concept that most reaction steps proceed only at the surface layer of a bulk catalyst, the catalytic impact of the surface-modification with POx, BOx, and MnOx in...

The Catalytic Function of Phosphorus Enriched on the Surface of Vanadium‐based Catalysts in Selective Oxidations

“…Therefore, only a small deviation in the determined specific surface area or the specific pore volume is observed (see Table SI2 and Figure SI6 for details on the N 2 ‐physisorption experiments). In addition, the surface modification does not change the morphology of the samples and no additional phases are formed, due to the solvent free method at temperatures below the calcination temperature of the base catalysts [36] …”

“…As the modification happens exclusively at the surface or solid‐gas interface, a characterization of this effect is limited to surface‐sensitive methods. In a recent publication it has been demonstrated how catalytic properties like the oxidation state of the redox active element V at the near‐surface or the acidity can be tuned by the surface deposition with PO x or BO x [36] . The intensity of the effects is always a function of the used base material, the deposited element and the amount or ALD‐cycle applied to the catalyst.…”

“…For deconvolution of the V 4+ /V 5+ species, only the V 2p 3/2 region is used as the V 2p 1/2 overlaps with an O1s satellite (see Figure SI12) [41] . The two peaks located at 518,2 eV and 516,8 eV, correspond to V 5+ and V 4+ , respectively [36,43] . No further oxidation states of vanadium species were detected.…”

“…Phenomenon beyond comprehension require a reduction in complexity to achieve a full understanding, for instance by using model systems. The presence of P was proven in multiple studies to tune the catalytic properties in different reactions on various V‐containing catalysts [17,35,36,37] . PO x introduced to the surface of the simple binary oxide V 2 O 5 [37,38] could be demonstrated to elevate the performance in n ‐butane oxidation from full combustion towards increased MAN selectivities [17,36,37] .…”

“…The presence of P was proven in multiple studies to tune the catalytic properties in different reactions on various V-containing catalysts. [17,35,36,37] PO x introduced to the surface of the simple binary oxide V 2 O 5 [37,38] could be demonstrated to elevate the performance in n-butane oxidation from full combustion towards increased MAN selectivities. [17,36,37] The surface decoration of bulk catalysts using atomic layer deposition (ALD) [39,40] as a solvent-free technique allows to elucidate on the influence of different elements without changing the basic features of the base material.…”