Pt₃Ti Intermetallic Alloy Formed by Strong Metal–Support Interaction over Pt/TiO₂for the Selective Hydrogenation of Acetophenone

Abstract

The strong metal−support interaction over Pt/TiO 2 catalysts, which were prepared by depositing size-specified Pt colloids (2−6 nm) onto anatase TiO 2 nanosheets dominated by the reactive {001} facets, was featured by the formation of Pt 3 Ti intermetallic alloy and showed a size-dependent effect. After H 2 reduction at 773 K, bulk Pt−Ti alloys in a mixture of disordered and ordered phases were readily formed over 2 nm Pt particle, while Pt 3 Ti intermetallic alloys, with a thickness of up to 6 atomic layers, were observed on 4−6 nm Pt particles, showing as a Pt 3 Ti@Pt core−shell architecture where the Ti atom substituted the Pt atom periodically and interacted with the Pt atom electronically. By further raising the temperature for H 2 reduction to 873 K, the 2−6 nm Pt particles turned into well-crystallized Pt 3 Ti intermetallic alloys. Both bulk Pt−Ti and Pt 3 Ti intermetallic alloys suppressed considerably the chemisorption of H 2 and CO but dramatically promoted the selectivity for hydrogenating the C�O bond in acetophenone.

CO-Assisted Methane Oxidation into Oxygenates over Surface Platinum–Titanium Alloyed Layers

“…Notably, the signal of the O species was absent, excluding the possible existence of any TiO 2– x overlayers over Pt nanocrystals. Compared with the characteristic peaks of Ti species on the TiO 2 support, the EELS edge position of titanium on Pt nanocrystals was shifted to a lower energy by 2.4 eV, indicating the formation of the surface Pt–Ti alloy. , The HAADF-STEM image and a high-resolution TEM (HRTEM) image on 0.1% Pt/TiO 2 also showed that the Pt nanocrystal was not covered by TiO 2– x overlayers (Figure h and Figure S3), agreeing well with the EELS results. As shown in the red dashed rectangle in Figure h, the surface layer exhibited an alternate arrangement of bright and dim spots.…”

Photocatalytic reduction of biomass‐derived aldehydes over Pt‐loaded on NiIn bimetallic oxides under light‐emitting diode lighting at mild conditions

“…This can be attributed to the lower energy barrier for C=C hydrogenation compared to C=O bond hydrogenation. 55,56 Additionally, the catalyst's activity was hindered for the steric hindrance.…”

Constructing Gradient Orbital Coupling to Induce Reactive Metal–Support Interaction in Pt-Carbide Electrocatalysts for Efficient Methanol Oxidation

“…Similar induction conditions make the occurrence of RMSI in metal–metal oxide systems often accompanied by cSMSI, which is often detrimental to catalytic activity. To avoid concomitant cSMSI, nonmetal oxide supports, such as Mxene, S-doped graphene, and Co–N–C, have been reported to induce RMSI. − At present, RMSI can be only induced by the thermal reduction method, and the onset temperature of RMSI is affected by both properties of the metal NPs and reducibility of the supports. − For instance, Shen et al found that the larger size of Pt NPs requires a higher onset temperature to form Pt 3 Ti alloy on TiO 2 . Besides, RMSI can also take place at a lower temperature when the supports are more easily to be reduced, for instance, the temperature required for RMSI in Pd–Ga 2 O 3 and Pt–ZnO systems is 250 and 500 °C, respectively.…”

“…26−29 For instance, Shen et al found that the larger size of Pt NPs requires a higher onset temperature to form Pt 3 Ti alloy on TiO 2 . 30 Besides, RMSI can also take place at a lower temperature when the supports are more easily to be reduced, for instance, the temperature required for RMSI in Pd−Ga 2 O 3 31 and Pt−ZnO 32 systems is 250 and 500 °C, respectively.…”