Catalytic oxidative conversion of methane and ethane over polyoxometalate-derived catalysts in electric field at low temperature

Role of Electric Field and Surface Protonics on Low-Temperature Catalytic Dry Reforming of Methane

“…As a result, NiO was reduced at 600–750 K and the part of La-ZrO 2 was reduced at 900–1000 K. The difference for the reduction temperature among these catalysts was not observed. Reportedly, proton conduction via adsorbed water on the catalysts surface proceeds more readily at a range of lower temperatures such as 423 K. The surface protonics on the catalyst surface promote several reactions. − Therefore, to investigate proton conduction in DRM with the electric field, the logarithmic apparent electrical conductivity was calculated as a function of inverse temperatures with the electric field at the same temperatures of Table , as depicted in Figure . Consequently, the electrical conductivity in DRM reaction increased in the range of lower temperatures such as 423 K. For that lower temperature range, it is known that increasing the amount of surface H 2 O species and hydroxyl groups increases the proton conductivity. , Therefore, proton conduction occurred from surface proton species derived from CH 4 via a reverse water gas shift reaction (RWGS: H 2 + CO 2 → CO + H 2 O) and surface hydroxyl groups on La-ZrO 2 .…”

“…So, the promotion for DRM activity was not due to increasing the temperature. Besides, many other reactions were also promoted by application of an electric field. − Surface protonics, with surface proton hopping via adsorbed water and hydroxyl groups, the so-called Grotthuss mechanism, − on the CeO 2 surfaces promotes catalytic performance. , The rate-determining step of conventional SRM (without the electric field) is known to be CH 4 dissociative adsorption step over Ni and precious metal-supported catalysts. , Proton collision to CH 4 in SRM with the electric field enables the formation of a transitional state and configures the three-atom (CH 3 –H–H) + transition state . Additionally, the energy level of produced (CH 3 + + H 2 ) was much lower than CH 4 physisorption and the transition state.…”

Selective catalytic and kinetic studies on oxydehydrogenation of ethane with CO2 over lanthanide metal catalysts

“…Many scholars who study polymetallic catalysts use this characteristic of Ce to regulate the catalyst in order to make the catalyst have high C 2 H 6 conversion and C 2 H 4 selectivity [48][49][50].…”

Conversion of methane to C2 and C3 hydrocarbons over TiO2/ZSM-5 core–shell particles in an electric field

“…23 Sekine and coworkers recently reported a Ce-W-O catalyst derived from CeO 2 modied with Ce 2 (WO 4 ) 3 polyoxometalate, which exhibited high OCM activity due to a synergetic effect between the Ce 2 (WO 4 ) 3 structure and the electric eld to produce the reactive oxygen species for the selective oxidation of CH 4 . [24][25][26] The CePO 4 nanorods with uniform surface Ce sites could work as a durable catalyst and showed the highest C 2 yield of 18% in an electric eld without the need for external heating. 27 More recently, McEwen and co-workers have reviewed some of the theoretical methods that have been used to elucidate the inuence of external electric elds on catalytic reactions, as well as the application of such methods to selective methane activation.…”