Paper-structured catalyst containing CeO2–Ni flowers for dry reforming of methane

Abstract

In this paper, ceria flowers containing nano-sized catalyst Ni particles were prepared on alumina-silica fiber network for production of hydrogen from biogas. The CeO2 flowers were prepared using hydrothermal method and then NiO was loaded on the CeO2 flowers by impregnation method. The Paper-structured catalysts (PSCs) were prepared from alumina-silica fibers and the CeO2–NiO flowers using conventional paper making method. The loaded NiO particles were uniformly dispersed on the CeO2 flowers with the use of polyvinylpyrrolidone as a dispersion enhancer, which was observed by FE-SEM and EDX analysis. The NiO particles were then reduced into Ni by using H2. The PSCs containing CeO2–Ni flowers with various Ni contents (2.1, 3.4, and 4.6%) were used for dry reforming of CH4. It was found that 3.4% amount of Ni on the PSC was suitable for reforming reaction, and the higher amount of Ni (4.6%) did not increase the CH4 conversion. The PSC with the CeO2 flowers had porous structure and large surface area leading to the better dispersion of the Ni particles with smaller size. This helped increase in catalytic performance, prevention of agglomerated particle catalysts at high temperature and coke forming after a long time operation. The CH4 conversion of the PSCs containing CeO2–NiO flowers in the dry reforming of CH4 was much higher (nearly 90%) with a smaller Ni content in comparison with the PSC without the CeO2 flowers (with higher Ni content of 8.6%). Moreover, the PSCs with the flowers exhibited an excellent catalytic stability with the degradation of CH4 conversion of only 3.1% after 50 h of reforming. In addition, the high oxygen storage capacity and oxygen mobility of CeO2 resulted in a partial removal of coke forming on the catalyst particles during reforming. This indicated that the catalytic activity of the Ni particles dispersed on the CeO2 flowers for dry reforming of CH4 was superior to that of various Ni-based catalyst systems which had much higher Ni contents. Therefore, it is possible to use the PSCs containing CeO2–Ni flowers to generate hydrogen for use as fuels from dry reforming of CH4.