Optimum calcination temperature in the synthesis of a N-C-S co-doped TiO2 photocatalyst, as monitored by neutron diffraction

Abstract

Calcination of a co-doped (N-C-S) TiO2 photocatalyst has been done following the whole process by neutron diffraction (instrument D1B of the ILL) with the objective of study the transition between two crystalline phases: anatase and rutile in order to find the optimum temperature leading to the coexistence of both for this catalyst whose band gap has been shifted to give activity in the visible part of the electromagnetic spectrum. This coexistence is important as it has been established that these catalyst are more efficient than those having only one individual phase. At this respect, it is very important to find the optimum temperature at with synthesis has to be done. In this research it was established that at the heating ramp of 17°C/5 min, the coexistence of both crystalline phases took place within a narrow margin of temperatures between 610°C and 690°C. At higher temperatures only rutile can be identified as the crystalline phase of the TiO2.