Unveiling the competitive interplay of interfacial and electronic effects in pickering emulsion catalysis for deep desulfurization

Deep oxidative desulfurization (ODS) of fuels in biphasic systems is fundamentally limited by sluggish liquid-liquid interfacial mass transfer and poor intrinsic affinity between catalysts and hydrophobic sulfur substrates. To overcome these bottlenecks, we rationally designed phosphotungstic acid (HPW)-anchored SiO 2 Janus nanosheets (JNSs) grafted with flexible n-hexyl (C6-JNS@HPW) or rigid phenyl (pH-JNS@HPW) groups to construct a high-efficiency Pickering interfacial catalytic (PIC) system. Systematic evaluation revealed a dynamic competitive mechanism between physical interfacial expansion and molecular electronic interactions. At a low catalyst dosage, flexible C6 chains endow superior dispersibility and a larger reactive interfacial area, achieving a 6.85% higher desulfurization rate than the Ph-modified counterpart. In contrast, pH-modified JNSs exhibit superior reaction kinetics under interface-saturated conditions. DFT calculations confirm that electron-rich Ph groups induce targeted π-π stacking interactions with DBT, optimize the local electronic microenvironment, and synergistically accelerate the deep oxidation of DBT dominated by superoxide radicals. This work shifts the paradigm of multiphase catalyst design from bulk empirical synthesis to precise microenvironmental engineering, providing critical insights into the interplay between interfacial and electronic effects.