Voltammetric characterization of structural titanium species in zeotypes

Ti4+ ions structurally contained in titanium silicalite (TS-I) and ETS-10 s amples, two nanoporous materials, have been studied by means of voltammetri c measurements. Both structurally tetrahedral and octahedral Ti4+ ions show electrochemical response. In particular, by using acid solutions, it was p ossible to distinguish, in TS-1, between signals coming from different tita nium species. Finally, it has been proven that the use of acid solutions al lows us to discriminate between Ti4+ ions in TS-I and in ETS-10 since only the former is able to coordinate water molecules, the reduction of which ca n be monitored by the presence of a peak at - 600 mV/SSE. (C) 2000 Elsevier Science S.A. All rights reserved.