Effect of metal-support interaction on activity and stability of Ni-CeO2 catalyst for partial oxidation of methane

- Nanocrystalline Ni-CeO2 catalyst is prepared by two step synthesis method.
- The catalyst showed superior catalytic activity for partial oxidation of methane.
- The catalyst can activate methane as lower as 400 °C to produce synthesis gas.
- The catalyst produce H2/CO ratio of 1.98 without deactivation till 90 h at 800 °C.
- Ni-species size controlled the coke deposition over catalyst surface.

The objective of the current study was to synthesize a nickel based catalyst with high activity at low temperature for partial oxidation of methane (POM). Ni-nanoparticles supported on CeO2 nanoparticles were synthesized by two step preparation method. First, 30-50 nm CeO2 was synthesized by solvo-thermal method and then Ni- nanoparticles were deposited over it following a newly developed procedure, where cetyltrimethylammonium bromide (CTAB) acted as morphology controlling agent and polyvinylpyrrolidone (PVP) as size controlling agent for nickel nanoparticles. The characterizations of synthesized catalysts were done by BET-Surface area, XRD, SEM, TEM, TPR, H2-chemisorpton, TGA and XPS analysis. The catalysts showed excellent coke resisting ability during POM and produces synthesis gas with H2/CO ratio almost 2. The catalyst activated methane at 400 °C with 10% methane conversion and converts methane almost completely at 800 °C. The catalyst showed above 98% methane conversion at 800 °C during 90 h of time on stream (TOS) reaction with H2/CO ratio 1.98. Average 5.5 nm Ni particles, use of CeO2 as a support played a very crucial role for methane activation at such lower temperature. The synergistic effect between small Ni-nanoparticles and CeO2 nanoparticles of Ni-CeO2 catalyst is the main reason for such activity. Detailed study of other reaction parameters like temperature, Ni loading, weight hourly space velocity (WHSV) was also carried out and reported.

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