Kinetics evidence for oxidized-site ensemble effects in surfactant-modified vanadium phosphorus oxide catalysts for n-butane oxidation

Selective oxidation of n -butane to maleic anhydride (MA) is fundamentally limited by the activity-selectivity trade-off, and the origin of selectivity control remains debated. Here we show that surfactant-mediated modification of vanadium phosphorus oxide catalysts can shift the reaction network toward MA by suppressing competing carbon oxides (CO x ) formation. We establish a kinetic framework that explains this selectivity shift through coupled redox-site balance and product-branching kinetics. Kinetic analysis identifies the CO x to MA branching parameter (