AuFe3@Pd/?-Fe2O3 Nanosheets as an In Situ Regenerable and Highly Efficient Hydrogenation Catalyst

Heterogenous Pd catalysts play a pivotal role in the chemical industry; however, it is plagued by S2- or other strong adsorbates inducing surface poisoning long term. Herein, we report the development of AuFe3@Pd/gamma-Fe2O3 nanosheets (NSs) as an in situ regenerable and highly active hydrogenation catalyst. Upon poisoning, the Pd monolayer sites could be fully and oxidatively regenerated under ambient conditions, which is initiated by center dot OH radicals from surface defect/FeTetra vacancy-rich gamma-Fe2O3 NSs via the Fenton-like pathway. Both experimental and theoretical analyses demonstrate that for the electronic and geometric effect, the 2-3 nm AuFe3 intermetallic nanocluster core promotes the adsorption of reactant onto Pd sites; in addition, it lowers Pd's affinity for center dot OH radicals to enhance their stability during oxidative regeneration. When packed into a quartz sand fixed-bed catalyst column, the AuFe3@Pd/gamma-Fe2O3 NSs are highly active in hydrogenating the carbon-halogen bond, which comprises a crucial step for the removal of micropollutants in drinking water and recovery of resources from heavily polluted wastewater, and withstand ten rounds of regeneration. By maximizing the use of ultrathin metal oxide NSs and intermetallic nanocluster and monolayer Pd, the current study demonstrates a comprehensive strategy for developing sustainable Pd catalysts for liquid catalysis.

Automated summary

In this study, AuFe3@Pd/gamma-Fe2O3 nanosheets were developed as an in situ regenerable and highly active hydrogenation catalyst. The Pd monolayer sites could be fully regenerated under ambient conditions, initiated by center dot OH radicals from gamma-Fe2O3 nanosheets. The nanosheets exhibited high activity in hydrogenating the carbon-halogen bond and withstand ten rounds of regeneration.