Infiltrate Mesoporous Silica-Aluminosilicate Structure Improves Hydrogen Production via Methane Decomposition over a Nickel-Based Catalyst

Abstract

A potential nickel-supported infiltrate mesoporous silica-aluminosilicate (Ni/SAS) catalyst was developed for improving hydrogen production through methane decomposition reaction. Infiltrate mesoporous silica-aluminosilicate supports with different Si/Al ratios (25, 50, and 100) were synthesized through a sol–gel method, then nickel metal was loaded on the support using an incipient impregnation method. All SAS(x) supports revealed a bimodal mesoporous structure with pore sizes at 2.7 and 3.9 nm. The aluminum favorably incorporated into the silica framework in the tetrahedral-coordinated position as [AlO4]5– to form an aluminosilicate framework in the structure of SAS(50). The active nickel area of Ni/SAS(x) catalysts was 1.30–2.27 times higher than that of the Ni/MCM-41 catalyst. Using the Ni/SAS(x) catalyst in the cracking reaction gave a higher H2 yield than using a Ni-supported silica catalyst. In particular, the H2 yield of the Ni/SAS(50) catalyst was 1.45, 1.11, and 1.29 times higher than that of the Ni/MCM-41 catalyst at 500, 550, and 600 °C, respectively. This performance could be attributed to a promotional effect of the infiltrate aluminosilicate framework as well as the moderate surface acidity, which enhanced the Ni dispersion and interaction between Ni and the SAS support, resulting in the multi-walled carbon nanotube formation via a tip-growth mechanism. Consequently, the active surface of the Ni/SAS(50) catalyst remained constant throughout the methane decomposition reaction.