Abstract:
Four nickel catalysts supported on cerium zirconyl oxide, 5%Ni/Ce0.6Zr0.₄O₂, were prepared. The supports were synthesized by surfactant-assisted templating route using cetyltrimethyl ammonium bromide (CTAB) at various amounts, and nickel deposition was then introduced by impregnation. Another Ni catalyst supported on cerium zirconyl oxide prepared by co-precipitation method was used for comparison. The catalysts were characterized by N₂ physisorption, XRD, RS, XPS, TPR, and TG-DSC. The catalytic performance and carbon deposition in the catalytic dry reforming of CH₄ (CDRM) with and without steam were investigated. The CH₄ and CO₂ conversion as well as the formation of H₂ and CO were concomitantly analysed by gas chromatography for 8 hours of reaction. The results showed that all catalysts prepared by surfactant-assisted templating route had higher activity and stability than the catalyst prepared by co-precipitation method. The addition of steam to the reaction did not increase the CH₄ conversion but decreased the carbon deposition. In addition, ten ternary mixed oxide supports, CeZrMO₂, where M is a transition, inner-transition or non-transition metal ion were prepared by surfactant-assisted templating route and then impregnated with Ni. It was found that the doping metals enhanced oxygen storage capacity and thermal stability of the supports comparing to the binary mixed oxides, resulting in a better catalytic performance in CDRM. The addition of steam in the reaction using ternary mixed oxide catalysts slightly increase the conversion of CH₄ and significantly decrease in carbon deposition. Moreover, the catalysts showed good stability in CDRM even at temperature as low as 500°C.
