Ni-Sr/TiZr for H2 from methane via POM: Sr loading & optimization.

Achieving remarkable H2 yield with significantly high H2/CO over Ni-based catalysts through partial oxidation of methane (POM) is a realistic approach to depleting the concentration of CH4 and using H2 and CO as synthetic feedstock. This study examined Ni catalysts on titania-zirconia for methane conversion via POM at 600 °C and atmospheric pressure. The addition of strontium to the catalyst was explored to improve its performance. Catalysts were characterized by X-ray diffraction, Raman-infrared-UV-vis spectroscopy, and Temperature-programmed reduction-desorption techniques (TPR, TPD). 2.5 wt% Sr addition induced the formation of the highest concentration of extreme basic sites. Interestingly, over the unpromoted catalyst, active sites are majorly generated by hardly reducible NiO species whereas upon 2.5 wt% promoted Sr promotional addition, most of active sites are derived by easily reducible NiO species. 45% CH4 conversion and 47% H2 yield with H2/CO = 3.5 were achieved over 2.5 wt% Sr promoted 5Ni/30TiO2 + ZrO2 catalyst. These results provide insight into the role of basic sites in enhancing activity through switching indirect pathways over direct pathways for POM. Further process optimization was carried out in the range of 10 000-22 000 SV, 0.35-0.75 O2/CH4, and 600-800 °C reaction temperature over 5Ni2.5Sr/30TiO2 + ZrO2 by using central composite design under response surface methodology. The optimum activity as high as ∼88% CH4 conversion, 86-87% yield of H2, and 2.92H2/CO were predicted and experimentally validated at 800 °C reaction temperature, 0.35O2/CH4 ratio, and 10 000 space velocity.

Optimizing Hydrogen Production: Influence of Promoters in Methane Decomposition on Titania-Modified-Zirconia Supported Fe Catalyst.

This study addresses the pivotal challenge of hydrogen production through methane decomposition, offering a pathway to achieving clean energy goals. Investigating the utilization of titania-modified zirconia dual redox supports (10TiZr) in iron or doped iron-based catalysts for the CH4 decomposition reaction, our research involves a thorough characterization process. This includes analyses of the surface area porosity, X-ray diffraction, Raman-infrared spectroscopy, and temperature-programmed reduction/oxidation. The observed sustained enhancement in catalytic activity over extended durations suggests the in situ formation of catalytically active sites. The introduction of Co or Ni into the 30Fe/10TiZr catalyst leads to the generation of a higher density of reducible species. Furthermore, the Ni-promoted 30Fe/10TiZr catalyst exhibits a lower crystallinity, indicating superior dispersion. Notably, the cobalt-promoted 30Fe/10TiZr catalyst achieves over 80% CH4 conversion and H2 yield within 3 h. Additionally, the Ni-promoted 30Fe/10TiZr catalyst attains a remarkable 87% CH4 conversion and 82% H2 yield after 3 h of the continuous process.