WO3 dehydration and phase transition as the catalytic driver of hydrogen production by non-calcinated WO3

In this study, WO3 (trioxide tungsten) was investigated as a catalyst for water reduction by NaBH4 in basic conditions, which are not typical for NaBH4 reduction processes. The results indicate that the structure of the WO3 phase strongly affects the catalytic process. The uncalcinated WO3, ncWO3, which contains primarily tungstite with traces of hydro-tungstite is the only WO3 form that acts as an effective catalyst. A cubic WO3 is formed or exposed during the reduction process. Hydrogen production increases during reaction cycles; an interesting and important result. Plausible mechanisms of the catalytic process observed are outlined. The results have farreaching effects that should be further investigated in other systems, such as the phase structures acting as a catalyst for treating toxic organic compounds. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.