Behavior of mesoporous silica under 2 MeV electron beam irradiation

This work deals with the evolution of the mesoporous structure of two silicas MCM-41 and SBA-15 under a 2 MeV electron beam as a function of the dose (0–5 GGy). For a dose of 2 GGy, the pore volume of the two materials decreases significantly by 40–45%. The irradiation-induced porosity closure is significantly more effective on smaller pores, resulting in a loss of the mesoporous network concerning MCM-41 (pore diameter ∼ 3.8 nm) and the conservation of the SBA-15 one (pore diameter ∼ 7.0 nm). The mechanism of silica porosity closure/collapse has not been fully identified, but it might result from damage effects as “Knock-on” processes. From a technological point of view, this phenomenon could be exploited for RadioNuclides (RN) encapsulation in a self-evolving porous material.