Enhanced hydrogen production from cracking of liquid toluene by applying liquid plasma and perovskite catalysts

Abstract

In this study, a process for producing hydrogen from liquid hydrocarbons by applying plasma is proposed. Toluene was decomposed by discharging a pulse-type plasma into liquid toluene directly. The changes in the rate of hydrogen production and reaction characteristics owing to injecting a perovskite catalyst were also investigated. A high hydrogen production rate of approximately 130 NL/h·g was obtained from the liquid–phase plasma reaction of toluene using the BiFeO3 catalyst. The investigation into the reaction characteristics based on the plasma generation conditions indicated that the reaction was mainly affected by the plasma voltage. When titanium dioxide and perovskite (SrTiO3, BiFeO3) photocatalysts were applied to this reaction, the reaction activities also varied depending on the light-absorption capacity of the catalysts. The highest hydrogen evolution rate was obtained using the BiFeO3 catalyst, which absorbs visible light as well as UV light, compared with the TiO2 photocatalyst, which absorbs only UV light. Because the plasma emission from toluene is predominantly in the visible region, the reaction activity was also determined to be the highest for the BiFeO3 catalyst. The BiFeO3 absorbs visible light up to about 550 nm, and it has a small bandgap energy of about 2.15 eV. This led to high photocatalytic degradation activity in visible light generated by plasma discharge in toluene. The carbon obtained had a particle size of less than 20 nm and purity of approximately 99%.