4-Mercaptobenzoic acid-anchored ultrafine Ag nanoparticles for efficient CO2 electrochemical reduction

It is very important to design model catalysts to control the site distribution and develop methods to improve their electronic environment and thus promote the catalyst's performance in the electrochemical reduction of CO2 (CO2RR). In this work, a strategy of in-situ synthesis and anchoring of nanoparticles (SSAN) was developed. Using this strategy, a jujube-cake type catalyst was designed, referred to as Ag@4-MBA. In this catalyst, Ag nanoparticles (NPs) act as jujube, which are embedded in 4-mercaptobenzoic acid (4-MBA) acting as cake. A Pointer-shaped Ag@4-MBA material was prepared that achieved high loading of Ag species (similar to 24.0 wt%), high dispersion (5-10 nm), high CO mass activity (93.7 A gAg(-1)), high CO faradaic efficiency (94.0%) and high CO production (2.0 mol gAg(-1) h(-1)), showing a superior performance to that of the recently reported Ag-based cata-lysts. Density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) characterization showed that a high degree of electron delocalization of the Ag-S-aromatic ring and reconstructing the electronic environment of the metal sites were achievied, it is beneficial to stabilize the reaction intermediate COOH*. This work provides a new approach for the design of metal nanoparticle model catalysts with more sustainable CO2RR.

Automated summary

In this study, a strategy of in-situ synthesis and anchoring of nanoparticles was developed to design an excellent catalyst for CO2 electrochemical reduction. The designed jujube-cake catalyst, Ag@4-MBA, exhibited high loading of Ag species, dispersion, CO mass activity, faradaic efficiency, and CO production. DFT calculations and XPS characterization revealed that the electronic environment of the metal sites was optimized, promoting the stabilization of the reaction intermediate COOH*.