Enhancing oxidative hydration of ethylene towards ethylene glycol over metal-modified titanosilicate catalysts

Metal-dopant modification is a promising approach to enhance the catalytic performance of titanium silicate molecular sieve. Herein, titanium silicalite-1 (TS-1) with different titanium contents and a series of metal-doping modified TS-1 are prepared, to enhance the synthesis of ethylene glycol (EG) through oxidative hydration of ethylene. The EG selectivity show a volcano relationship along with the increase of Ni addition, and reach maximum in 80.63 % at 0.13 wt % Ni loading. The Ni promoter mechanism is revealed that NiO species enhances the electropositivity of skeleton Ti and neutralizes the surface acidity of TS-1, which improves the efficient utilization of H 2 O 2 and selectivity of EG. Furthermore, Ni-modified TS-1 shows superior stability to TS-1, as well as satisfactory reusability since the deactivation of catalyst is reversible through high-temperature calcination. This work demonstrates the feasibility and mechanism of Ni promoter and provides a promising strategy for the development of TS-1 catalysts. • The promoter role of Ni in Ni-TS-1 zeolite over oxidative hydration of ethylene is studied. • The effective utilization of H2O2 and selectivity of EG over Ni-modified TS-1 are superior to TS-1. • The Ni species neutralizes the acidity of TS-1 zeolite to prevent the continuous polymerization of ethylene glycol. • The moderate addition of Ni enhances the electrophilicity of skeleton Ti, which is conducive to the adsorption of H2O2.