Single-Atom Au^I–N₃ Site for Acetylene Hydrochlorination Reaction

Abstract

The gold-catalyzed acetylene hydrochlorination reaction is an important process to produce vinyl chloride monomer in the polyvinyl chloride industry. The traditional catalyst of carbon-supported AuCl 3 is inclined to be reduced by acetylene and lose its activity during the reaction process. Here, we presented the construction of Au I −N 3 active sites through single gold atom dispersed on g-C 3 N 4 (Au 1 /g-C 3 N 4 ), which shows robust catalytic performance toward acetylene hydrochlorination. The Au species is shown to have Au I oxidation state, and it is coordinated with three nitrogen atoms of tri-s-triazine repeating units, which is consistent with density functional theory (DFT) modeling and XAFS measurements. Through DFT study, we demonstrate that the Au I −N 3 sites tend to coordinate with HCl than C 2 H 2 in the initial reaction. The Au I −N 3 sites cannot be reduced into Au 0 oxidation state easily and thus maintain their activity as stable catalytic active sites. The single-atom-site Au catalyst with nitrogen coordination environment and corresponding electronic state provides an efficient pathway for acetylene hydrochlorination reaction.

Development of gold catalysts supported by unreducible materials: Design and promotions

“…It was successfully deposited on mostly reducible supports, such as FeOx, CeO2, and ZnZrO4 [166−168]. Only several reports implied the successful deposition of atomic Au on the unreducible supports such as multi-wall carbon nanotubes (MWCNTs), zeolites, and mesoporous silica [42,169,170]. However, huge opportunities and challenges co-exist regarding the use of Au SACs for the heterogeneous reaction.…”

Single Metal Atom Decorated Carbon Nitride for Efficient Photocatalysis: Synthesis, Structure, and Applications

“…Chen et al confirmed the electronic environment and bonding state of Au atoms on the surface of carbon nitride. [ 87 ] They found that on the C defects of g‐C 3 N 4 , Au atoms tend to coordinate with the N atoms to form electron‐deficient centers. This coordination causes the charge supports to transfer from the Au atoms embedded in g‐C 3 N 4 to the adjacent N atoms.…”

“…Specifically, the lone electron pairs of N atoms are able to bind with SMAs with empty or partially filled orbitals. Therefore, the construction of photocatalysts with metals, such as Pd, [ 11–14 ] Pt, [ 15–17 ] Au, [ 18–22 ] Ag, [ 23,24 ] Co, [ 25–27 ] Fe, [ 28,29 ] Cu, [ 30–35 ] and Mn, [ 36 ] atomically dispersed on g‐C 3 N 4 has become highly anticipated. These SMAs are reactive themselves and therefore can increase the number of active centers tremendously, [ 37–46 ] giving rise to a new type of heterogeneous catalysis that is often referred to as SMA photocatalysis.…”

Triazine COF-supported single-atom catalyst (Pd1/trzn-COF) for CO oxidation

“…Usually, oxides are the most widely used supports for metal catalysts, where the defects on surface are specifically used to stabilize metal single atoms (SAs) [1,[20][21][22][23][24]. Besides, carbon-based supports doped with other heteroatoms also offer important donor sites for metal atoms, especially for Ndoped carbon materials and mesoporous polymeric graphitic carbon nitride (e.g., mpg-C 3 N 4 ), which can not only strongly anchor metal atoms but also regulate the electronic properties of the prepared SACs [25][26][27][28][29]. Currently, among the challenges of SACs, the amount of loading and the stability of metal SAs on the surface are the bottleneck for practical application of SACs [30,31].…”