Palladium/graphene quantum dots stabilizing Pickering emulsions for enhanced electrooxidation of benzylamine

Pickering emulsions offer a promising strategy to boost conversion, selectivity, and yield in electrochemical organic synthesis by stabilizing interfaces and facilitating efficient charge/mass transfer. Yet, challenges remain in improving the catalytic efficiency and unraveling the emulsion-dependent performance. In this study, palladium/graphene quantum dots (Pd/GQDs) are employed to stabilize Pickering emulsions for the efficient electrooxidation in immiscible oil-water electrolytes. GQDs, hydrothermally synthesized from 1,3,6-trinitropyrene and lauric acid, are used to anchor ultrasmall Pd nanoparticles, forming amphiphilic nanocomposites capable of stabilizing emulsions. Key parameters for emulsion formation, including organic phase composition, emulsification time, Pd/GQDs concentration, and oil-to-water ratio are investigated to understand their influence on emulsification and subsequent electrocatalytic performance. The optimized Pickering emulsion significantly enhances the electrooxidation of benzylamine to N-benzylidenebenzylamine, facilitated by the amphiphilic Pd/GQDs, which enable efficient separation of hydrophobic products from the electrocatalyst/electrolyte interface. This system achieves a high N-benzylidenebenzylamine selectivity of > 80% and a nearly sixfold increase in reaction efficiency compared to conventional single-phase electrolysis, demonstrating its promise to overcome the insoluble challenge of organic substrates in electrosynthesis.