Interfacial Microenvironment Engineering in Pickering Emulsion Electrocatalytic System for Selective Hydrogenation of 4-Nitrostyrene

Tuning reaction selectivity by modifying the microenvironment around active sites is an intriguing research focus in catalysis. Here, we show that the selectivity of 4-nitrostyrene hydrogenation can be modulated via interfacial microenvironment engineering in a Pickering emulsion electrocatalytic system, where an interfacial effect derived from the unique structure of the electric double layer and interfacial hydrogen-bonding interactions steers the hydrogen transfer pathway. Specifically, hydrophilic Pt/CNTs-AT preserves the intact interfacial hydrogen-bond network, facilitating efficient proton-coupled electron transfer that preferentially reduces the nitro group, thus achieving 95.2% selectivity for 4-aminostyrene. In contrast, hydrophobic Pt/CNTs-C18 disrupts the hydrogen-bond network and alters the electric double layer structure, promoting the formation of adsorbed hydrogen and thus directing the reaction toward C = C bond hydrogenation, with 93.3% selectivity for 4-nitroethylbenzene. This work provides new insights into the selective hydrogenation of multifunctional substrates, highlighting the critical role of interfacial microenvironment regulation in steering reaction pathways.