The Rh/Ni interaction in bimetallic Rh/Ni/Mg/Al hydrotalcite-type (HT) derived catalysts for the catalyticpartial oxidation (CPO) of CH4was studied modifying the preparation method. The conventional incor-poration of both Rh and Ni by coprecipitation (CP) of HT precursors was compared with the additionof Rh by chemical vapour deposition (CVD) to reduced Ni/Mg/Al HT-derived catalysts. Two Ni load-ings were selected (about 8 and 2 wt.%), whereas the Rh content was kept constant (0.18 wt.%). Ni- andRh-monometallic catalysts were prepared as reference materials.The addition of Rh resulted in an increase in Ni reducibility and dispersion for both CP and CVD cata-lysts. The Rh/Ni interaction was stronger in CP catalysts, while in CVD ones Rh overspread either on thesupport or Ni particles, with a preferential deposition on the latter. The Ni loading, regardless of the Rhincorporation method, was the main factor to determine the formation and growth of metallic particles.CO-DRIFTS spectra revealed that the dispersing and reducibility effect of Rh was more evident in thesamples with a lower Ni-loading.The small amount of Rh in the catalysts yielded to higher CH4conversions, especially in low Ni-containing catalysts wherein the Ni0oxidation was avoided. All the catalysts were activated duringcatalytic tests at high temperature by reduction of hardly reducible species. The strongest Rh/Ni inter-action in CP catalysts yielded to better performances with a lower carbon formation and high resistancetowards metallic particle sintering.
P. Benito, V. Dal Santo, V. De Grandi, M. Marelli, G. Fornasari, R. Psaro, et al. (2015). Coprecipitation versus chemical vapour deposition to prepare Rh/Nibimetallic catalysts. APPLIED CATALYSIS. B, ENVIRONMENTAL, 179, 150-159 [10.1016/j.apcatb.2015.05.016].
Coprecipitation versus chemical vapour deposition to prepare Rh/Nibimetallic catalysts
BENITO MARTIN, PATRICIA;FORNASARI, GIUSEPPE;VACCARI, ANGELO
2015
Abstract
The Rh/Ni interaction in bimetallic Rh/Ni/Mg/Al hydrotalcite-type (HT) derived catalysts for the catalyticpartial oxidation (CPO) of CH4was studied modifying the preparation method. The conventional incor-poration of both Rh and Ni by coprecipitation (CP) of HT precursors was compared with the additionof Rh by chemical vapour deposition (CVD) to reduced Ni/Mg/Al HT-derived catalysts. Two Ni load-ings were selected (about 8 and 2 wt.%), whereas the Rh content was kept constant (0.18 wt.%). Ni- andRh-monometallic catalysts were prepared as reference materials.The addition of Rh resulted in an increase in Ni reducibility and dispersion for both CP and CVD cata-lysts. The Rh/Ni interaction was stronger in CP catalysts, while in CVD ones Rh overspread either on thesupport or Ni particles, with a preferential deposition on the latter. The Ni loading, regardless of the Rhincorporation method, was the main factor to determine the formation and growth of metallic particles.CO-DRIFTS spectra revealed that the dispersing and reducibility effect of Rh was more evident in thesamples with a lower Ni-loading.The small amount of Rh in the catalysts yielded to higher CH4conversions, especially in low Ni-containing catalysts wherein the Ni0oxidation was avoided. All the catalysts were activated duringcatalytic tests at high temperature by reduction of hardly reducible species. The strongest Rh/Ni inter-action in CP catalysts yielded to better performances with a lower carbon formation and high resistancetowards metallic particle sintering.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
