Bioinspired Hydrophobic Single-Atom Catalyst with Flexible Sulfur Motif for Aqueous-Phase Hydrogenative Transformation

Abstract

Metalloenzyme-like metal–nitrogen–carbon (M–N–C) single-atom catalysts (SACs) have received increasing attention in the synthesis of fine chemicals because of the abundant atomic sites and versatile catalytic properties. However, the organic transformations with high atom efficiency over SACs in aqueous media were less investigated. Inspired by the hydrophobic pockets of the metalloenzyme, herein we introduced a hydrophobic, atomically dispersed Pd catalyst (Pd1–S–C) in the sulfur-doped carbon based on metal–sulfur coordination chemistry. This hydrophobic Pd-based SAC displayed satisfying catalytic performance for aqueous-phase semihydrogenation of terminal alkynes with high chemoselectivity, friendly substrate scope, and fairly good stability. Molecular dynamics simulations revealed that the hydrophobicity of the Pd1–S–C catalyst could contribute to accelerated reaction kinetics by enriching the organic alkynes around the catalytic sites in aqueous media. Furthermore, the electron-rich PdS4 single sites were demonstrated to promote activation of H2 molecules and desorption of CC intermediates, which outperformed the electron-deficient PdN4 single sites. The current work highlights the potential of enzyme-inspired hydrophobic SACs in the conversion of organic substrates in aqueous media.

Microenvironment Modulation of Ultrathin Bronze‐Phase TiO2 Nanosheets for Highly Selective Photocatalytic CO2 Reduction in Water

“…[ 25 ] To further uncover the important roles of H 2 O 2 in improving the photocatalytic CO 2 reduction reaction, the diffusion behaviors of the CO 2 gas in the two different systems, pure H 2 O ( Figure a) and the mixture solution of 5% H 2 O 2 ‐H 2 O (Figure 7b), were performed using the molecular dynamics (MD) simulation. [ 26 ] Mean‐squared displacement (MSD) analysis of the CO 2 gas movement (Figure 7c) indicated that the calculated CO 2 diffusion coefficient (DC, 0.787 cm 2 s −1 ) in the mixture solution system of 5% H 2 O 2 ‐H 2 O was greater than in the pure H 2 O system (0.525 cm 2 s −1 ). The result revealed that H 2 O 2 around the TBHO surface created a unique microenvironment, favored CO 2 gas diffusion in the reaction medium, which might provide an advantage to enhance the catalytic activity.…”

Single‐Atom Catalysis in Organic Synthesis

“…In this material, Pd single atoms were coordinated by sulfur, and the catalyst was used to perform semihydrogenation of alkynes to alkenes in water (Scheme 35). [74] The catalyst showed excellent reactivity and selectivity towards the alkenes, ca. >90 % over alkane byproducts.…”

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

“…The charge configuration of active site can directly affect the adsorption and desorption of reactants, thus changing the reaction energy barrier. The superior catalytic performance of SACs has been achieved by adjusting charge configurations [66][67][68][69]. Among them, the introduction of a second metal atom to construct a dual metal pair active site has been proved as a promising way to realized desired charge configurations for various reactions [70,71].…”