Structural Evolution of Anatase‐Supported Platinum Nanoclusters into a Platinum‐Titanium Intermetallic Containing Platinum Single Atoms for Enhanced Catalytic CO Oxidation

Abstract

Strong metal‐support interactions characteristic of the encapsulation of metal particles by oxide overlayers have been widely observed on large metal nanoparticles, but scarcely occur on small nanoclusters (<2 nm) for which the metal‐support interactions remain elusive. Herein, we study the structural evolution of Pt nanoclusters (1.5 nm) supported on anatase TiO2 upon high‐temperature H2 reduction. The Pt nanoclusters start to partially evolve into a CsCl‐type PtTi intermetallic compound when the reduction temperature reaches 400 °C. Upon 700 °C reduction, the PtTi nanoparticles are exclusively formed and grow epitaxially along the TiO2 (101) crystal faces. The thermodynamics of the formation of PtTi via migration of reduced Ti atoms into Pt cluster is unraveled by theoretical calculations. The thermally stable PtTi intermetallic compound, with single‐atom Pt isolated by Ti, exhibits enhanced catalytic activity and promoted catalytic durability for CO oxidation.

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

“…24 Vacuum-annealing a Pt/TiO 2 model catalyst (0.8 nm Pt clusters on the TiO 2 (110) surface) at 973 K led to the formation of ordered Pt−Ti intermetallic particles (2.4 nm). 26 Quite recently, STEM and XAFS studies on H 2 treatment of Pt clusters (1.5 nm), supported on anatase TiO 2 , found that Pt−Ti alloy formed partially at 673 K, grew epitaxially along the TiO 2 (101) facets, and eventually turned into ordered PtTi intermetallic alloy (2.2 nm) at 973 K. 27 We have recently found that Pt−Ti surface alloy on Pt particles of 3 nm, supported by anatase TiO 2 nanosheets, was formed readily at 673 K under H 2 and thus dominated the SMSI. 28 Apparently, substantial progress has been made to identify the diversity of SMSI for Pt/TiO 2 by controlling the size of Pt particles or tuning the surface property of TiO 2 .…”

Synergistically Mitigating Electron Back-Donation by Single-Atomic Fe–N–C and Alloying to Boost CO-Tolerance of Pt in Hydrogen Oxidation

“…One strategy is to alloy Pt with transitional metals to shift the Pt d band. − Watanabe et al reported that PtRu alloy could maintain 60% current density after 1800 s operation under 1000 ppm CO/H 2 , much higher than commercial Pt/C . By introducing more electrophilic transition metals like Ru, Pt tends to show slightly oxidative states, endowing 5 d orbital with more vacancies, thus reducing the electron back-donation of Pt 5 d → CO 2 π * and CO chemisorption. , Alternatively, the Pt electronic structure can also be modulated via the strong metal–substrate interaction (SMSI) by incorporating metal oxide substrates, such as TiO 2 , Ti 4 O 7 , etc. , Although this strategy was widely explored in thermal catalysis, − few examples have been demonstrated in HOR to enhance the CO tolerance of Pt-based electrocatalysts . Even with these efforts, the CO adsorption is usually still much stronger than H 2 , leading to CO accumulation and poisoning issues during operation. , It is currently a challenge to satisfactorily solve this issue via either alloying or SMSI strategy on Pt-based catalysts while retaining their HOR activity and stability.…”

Supported AgCuCl Nanoclusters as Bimetal Catalysts for Propylene Epoxidation with Molecular Oxygen

“…However, the stability of nanoclusters remains a major challenge for their applications in catalytic reactions. , To address this issue, appropriate supports have been used to stabilize the nanoclusters via strong metal–support interaction. Supported metal catalysts (SMCs) have been extensively studied in heterogeneous catalysis (catalytic oxidation, , catalytic reductions, etc.). To the best of our knowledge, there are no relevant studies on the DEP process with SMCs materials using nanocluster as the precursor.…”