Atomic-Layer-Deposition Derived Pt subnano Clusters on the (110) Facet of Hexagonal Al₂O₃ Plates: Efficient for Formic Acid Decomposition and Water Gas Shift

Abstract

The Pt subnano clusters dispersed on the (110) facet of regularly shaped hexagonal Al2O3 plates were fabricated via an atomic layer deposition approach. The resulting material contains Pt loading as low as 0.07 wt %; the interfacial structure exhibits nearly full CO conversion for water gas shift reaction at 210 °C, and the turnover frequency (TOF) of CO is as high as 2.1 s–1, outperforming most of the systems reported. The same interfacial structure was also found to be highly active for catalytic decomposition of formic acid (FA), with full FA conversion (with little CO product) and the TOF being 1.02 s–1. Further characterizations together with density functional theory simulations elucidate that the superior catalytic performances are attributed to the unique interfacial structure and the synergism between the small Pt clusters and the Al2O3 (110) substrate, leading to lower energy barriers for the *COOH intermediate formation over the ultrafine Pt ensembles and the hydroxylation over the Al2O3 (110) substrate close to the Pt entities. Both are favorable for the evolution of *COOH intermediate and the reaction between *COOH and neighbor OH species. The current study provides insights into the effectiveness in generating high-performance catalytic material for clean energy production and modulation through precise control of the metal entity dimension and the oxide substrate engineering to achieve specific facet exposure.

Atomic Layer Deposition of Pt Fine Clusters over the Structurally Defined SnO2 Facets for Efficient Formic Acid Decomposition and H2 Evolution

“…The obtained values (19.6 and 21.1 kJ/mol) are comparable over the two samples with very low Pt loading and notably lower than that measured on the previously reported catalysts. ,− In our case, the significant modification emerged in the electronic property and local coordination environment of the exposed Pt atoms, which are uniquely contacted to the (101)/(110) facets of r.d -SnO 2 and the (111) facet of o -SnO 2 ; the resulting interfacial structures possess the synergism favorable for FA activation and transformation. According to our previous DFT simulation study, the formation of COOH* is the rate-determining step for a water–gas shift. Since the water–gas shift and FA decomposition could share the similar intermediate, the lower E a values measured in this study imply that the FA activation and intermediate formation is easy over 0.05% Pt/ o- SnO 2 -ALD and 0.07% Pt/ r.d -SnO 2 -ALD.…”

“…In this way, metal particles with controllable particle sizes can be precisely deposited onto the structurally clear oxide support to establish unique metal–oxide interfaces applied for certain catalytic processes and to achieve a structure–performance correlation in depth. This is the major tactic of the present study, and such tactics have been successfully applied for a variety of catalyst systems and reactions in our lab. − …”

Effect of CeO2 Morphology in Catalytic Performance via Methanol Oxidative Steam Reforming for Hydrogen Production

“…which represents an empty position (anion-vacant site) originating from the removal of O 2– from the lattice, here represented as an oxygen tetrahedral site (Ce 4 O). Oxygen vacancies bind adsorbates more strongly than normal oxide sites and contribute to their dissociation. − The characteristics of the oxide support, including the density and reactivity of surface OH groups, are strongly influenced by the exposed surface structure of the oxide support. Different atomic configurations and crystal surfaces are typically revealed in different CeO 2 morphologies, which subsequently impact the catalyst’s performance.…”

Defect-driven nanostructuring of low-nuclearity Pt-Mo ensembles for continuous gas-phase formic acid dehydrogenation

“…Yet, fabrication of these advanced materials is still challenging. The current synthetic protocols are mainly relying on i) gas-phase/atomic layer depositions that require advanced synthesis facilities and complicated operation procedures 47 , or ii) wet chemistry methods wherein expensive metal carbonyl clusters are often used as the precursors 42 , plus the di culties in fabricating heteroatom ensembles with structural uniformity. To construct heteroatoms or multi-atom clusters, spatial con nement-pyrolysis strategy has been developed using porous materials like metal-organic frameworks or covalent-organic frameworks to prevent the sintering of different metal precursors, but is mainly limited to a few components such as Fe, Co and Ni 46 .…”