Effect of NiO supported SiO2 in high concentration of CO

The effect of a nickel oxide supported silica oxide (NiO/SiO2) catalyst on temperature programmed reduction (TPR) with 40% (v/v) carbon monoxide (CO) in nitrogen atmosphere as reductant agent was investigated. The conventional impregnation method was used to create the NiO/SiO2 catalysts. The reduction characteristics of NiO to Ni were investigated up to 700 °C, followed by isothermal reduction. The TPR profile of 9% NiO/SiO2 slightly shifted to lower temperature from 412 to 392 °C. Whereas the undoped NiO was reduced at a lower temperature of 387 °C. XRD diffractogram of the catalysts showed a complete reduction of NiO to Ni and have different intensities for each different loading of NiO catalyst on SiO2 support. The TEM images indicated that the carbon nanotubes were deposited on the NiO surfaces indicating some chemical reactions occur on NiO. It was found that the addition of 3% of NiO on SiO2 also exhibited a larger BET surface area (532.8 m2g−1) and insignificant pore diameter (5.9-6.0 nm). Based on these results, it is interesting to note that the addition of a small amount of NiO to SiO2 has a remarkable influence by reducing the temperature in the reduction process. The 9% NiO/SiO2 was found sufficient could enhance the reducibility of NiO at a lower temperature.