CH4 Decomposition to Green H2 over PM(1wt%)-Ni(20wt%)/MCM-41 (PM = Pd, Pt, and Rh) Catalysts

The CH4 is a greenhouse gas with a global warming potential(GWP) 21 times greater than CO2. The catalytic decomposition of CH4 (CDM) is a climate-friendly, CO2-free process that produces only green H2 and carbon nanomaterials such as carbon nanotubes. The CDM to green H2 over PM(1wt%)-Ni(20wt%)/MCM-41 (PM = Pd, Pt, and Rh) catalysts was investigated using a packed-bed flow reactor(PBFR) under atmospheric pressure. The catalysts were characterized through XPS and XRD. XRD analysis revealed that NiPd crystallites were formed owing to appropriate interactions between Ni2+ and Pd2+. XPS analysis revealed that adding of 1 wt% of Pd to Ni(20wt%)/MCM-41 increased the Ni2p atomic percentage of Pd(1wt%)-Ni(20wt%)/MCM-41 from 2.77% to 4.27%, and decreased that of O1s the from 68.59% to 66.92%. The core electron levels, such as Ni2p, O1s, and Si2p in fresh Pd(1)-Ni(20)/MCM had a slight chemical shift toward lower energy compared to those of Ni(20wt%)/MCM-41. The H2 yield on the Pd(1 wt%)-Ni(20wt%)/MCM-41 is much higher than that of PM(1wt%)-Ni(20wt%)/MCM-41 (PM = Pt, Rh) and Ni(20wt%)/MCM-41 even after 1.2 x 104 s of CDM, while that of Ni(20wt%)/MCM-41 decreased rapidly. The H2 yield of Pd(1wt%)-Ni(20wt%)/MCM-41 in CDM was enhanced owing to the increased Ni2p distribution and the enhanced reduction degree caused by H2 spillover via appropriate metal-carrier interaction (AMCI) between Pd, Ni, and MCM-41. The CDM is an environmentally friendly process that produces COx-free and economical green H2 by using a catalyst of 1 wt% Pd onto Ni(20wt%)/MCM-41.