In Situ High-Temperature Reaction-Induced Local Structural Dynamic Evolution of Single-Atom Pt on Oxide Support

Abstract

The dynamic evolution of active site coordination structure during a high-temperature reaction is critically significant but often difficult for the research of efficient single-atom catalysts (SACs). Herein, we for the first time report the in situ activation behaviors of the local coordination structure of Pt single atoms (Pt 1 ) during the high-temperature oxidation of light alkanes. The distinctly enhanced activity of the catalyst is attributed to the in situ evolved Pt 1 −oxygen vacancy (Pt 1 −OV) combination ensemble as an efficient and stable active site. Theoretical calculations reveal that the lattice oxygen adjacent to Pt 1 and the H dissociated from CH 4 constitute the lattice hydroxyl, which is the initial step in the formation of the Pt 1 −OV combination. Pt 1 and nearby unsaturated Mn can donate the charge back to O−O to promote the dissociation of O 2 . This work provides molecular-level insight into the in situ reaction-induced evolution of a single-atom coordination environment for designing efficient SACs under harsh conditions.

Computational Screening of Pt1@Ti3C2T2 (T = O, S) MXene Catalysts for Water–Gas Shift Reaction

“…The single-atom catalyst (SAC), − a new concept first proposed by Zhang, Li, and Liu et al, is regarded as one of the landmark studies in heterogeneous catalysis. In the past decade, a series of new concepts related to SACs have been derived based on the static and dynamic active center of the reaction and the atomic type of the active center, such as dynamic single-atom catalysts (DSACs), , single-cluster catalysts (SCCs), − which include the so-called dual-atom-site catalysts (DASCs), − single-atom alloy (SAA), − and nanosingle-atom-site catalysts (NSASCs). − Currently, SACs have been widely used in diverse photocatalytic, electrocatalytic, and thermal catalytic reactions such as CO oxidation, − H 2 production, CO 2 reduction, − N 2 fixation, − NO oxidation, WGS reaction, − and so on, − owing to their excellent catalytic activity and selectivity, clear-cut coordination environment of active centers, and the maximum atomic utilization of metals. − Especially, Lin et al reported a new SAC Ir 1 /FeO x , which shows higher catalytic activity than its cluster or nanoparticle counterpart, and even than the most active Au- or Pt-based catalysts for WGS reaction. Combined with experimental results, Liang et al systematically studied the catalytic mechanism of the WGS reaction using first-principles calculations, and proposed a new dual metal active site synergistic redox mechanism.…”