Steam methane reforming performance of Ni/Al2O3 composite catalysts prepared via a hydrothermal-infiltration method

Ni as a catalyst for steam methane reforming (SMR) was deposited on a porous Al₂O₃ support using a hydrothermal-infiltration method. The SMR performance of Ni/Al₂O₃ composites was strongly affected by the microstructural change of the support according to the firing temperature. While there was no significant change up to 800 ℃, significant grain growth and large interfacial necking occurred after firing at 1,200 ℃, resulting in a significant increase in both porosity and pore size. The Al₂O₃ support with a large pore size and broad pore size distribution could load a relatively larger amount of Ni catalyst during the hydrothermal-infiltration process and facilitate the diffusion of reaction gases. Therefore, the Ni/Al₂O₃ composite with the support fired at 1,200 ℃ exhibited the best SMR performance. Meanwhile, Ni catalysts were distributed evenly throughout the porous support in the Ni/Al₂O₃ composite prepared by the hydrothermal-infiltration method compared to that prepared by the conventional infiltration method. Therefore, the Ni/Al₂O₃ composite prepared by the hydrothermal-infiltration method exhibited much better SMR performance. Moreover, no significant performance degradation was observed at 600 ℃ for 100 h.