Boosting Stabilized Pickering Emulsion via Janus Materials for Efficient Interfacial Photoreforming Hydrogen Evolution

Interfacial photocatalysis has been developed; however, in liquid–liquid heterogeneous systems, photocatalytic efficiency remains limited by stability and mass transfer constraints. To address the challenges, we constructed a Pickering emulsion (PE) system stabilized by Janus-structured amphiphilic TiO2 nanoparticles (J-TiO2) at oil–water interfaces. The hydrophilic and hydrophobic groups on J-TiO2 were, respectively, extended into the water phase and oil phase (n-octanol) to stabilize the heterogeneous system for effective interfacial catalysis. The resulting J-TiO2-stabilized PEs exhibited a long-term stability (>35 days) and an enhanced hydrogen (H2) evolution rate of 185.6 μmol/g/h, with a total H2 production yield of 535 μmol/g, representing a 2.98-fold increase over the single aqueous phase and an 11.9-fold enhancement relative to the pure oil phase. Combining experimental analysis and molecular dynamics (MD) simulations, we demonstrated that the amphiphilic J-TiO2 effectively assembled at the oil–water interface, significantly reducing the interfacial tension and facilitating charge separation for the redox reaction. This work provides a new strategy for designing liquid–liquid heterogeneous photocatalytic PEs systems and modifying their interfacial structures for potential industrial applications.