Influence of substituent position and pH on organophosphates hydrolysis catalyzed by various nanocrystalline ceria

The dephosphorylation of naphthyl phosphate isomers was investigated on five different nanocrystalline ceria samples and at different pH to determine how physicochemical properties and reaction conditions affect catalytic performance. The reaction rate was consistently higher under acidic conditions for all samples, which was likely due to variations in the reaction mechanisms and the specific properties of ceria prepared by different methods. We also studied the adsorption of primary degradation products (naphthol isomers) and observed different adsorption capacities for individual samples, which may influence the overall reaction kinetics. In addition, FTIR analysis confirmed the presence of reaction residues on the ceria surface, which may also affect the reaction rate. The synthesis method influences the physicochemical properties of ceria, such as surface characteristics, stability, and catalytic activity. However, the position of the substituent on the organic backbone also significantly affected the decomposition of the selected organophosphorus compounds. The 2-naphthyl phosphate isomer (with the substituent in position 2) decomposed more rapidly on all samples, due to reduced steric hindrance from the organic backbone. • Reaction rates were higher under acidic conditions. • Ceria’s catalytic activity is influenced by substituent position and pH. • 2-NPPH decomposed faster due to lower steric hindrance. • FTIR confirmed a strong interaction of organophosphorus compounds with ceria