Tailor of frustrated Lewis pairs in Ag/CeO₂ for producing 4-aminophenol

Catalytic reduction of 4-nitrophenol (4-NP) pollutant to the high-value 4-aminophenol (4-AP) with a clean hydrogen donor holds significant importance yet great challenges owing to the difficult activation of nitro and H species. In this work, Ag tailoring Frustrated Lewis pairs (FLPs) of CeO₂ (Ag/CeO₂) were successfully fabricated for electrochemical reduction reaction of 4-NP (4-NP ERR). As a result, the bond of Ag with O atom changed the state of the Ce–O bond and electron density, where the tailored FLPs were the key factor for enhancing absorption and activation. The reaction rate of Ag/CeO₂ reached up to 4.70 μmol·min^-1 (Faraday efficiency: 99.5%), which was about four times of CeO₂. Additionally, this study delved into the proton-coupled electron processes to further understand the mechanism of 4-NP ERR. Therefore, in this study, we have endeavored to investigate the role of tailored FLPs sites and utilize this structure–function relationship to achieve environmental-friendly chemical synthesis.