Promotional Effect of Cu and Influence of Surface Ni-Cu Alloy for Enhanced H_2 Yields from CH_4 Decomposition over Cu-Modified Ni Supported on MCM-41 Catalyst

摘要

Catalysts based on MCM-41 decorated with 35-70 nm diameter Ni particles were tested for the production of hydrogen by catalytic decomposition of methane (CDM). About 122 N m(3) (mol(Ni))(-1) hydrogen yield was achieved over a catalyst comprised of optimized Ni loading of 50 wt % Ni/MCM-41. The H-2 yield increased dramatically to 204 N m(3) (mol(Ni))(-1), upon modification with 10 wt % Cu. The presence of Cu, in contact to Ni, appeared to reduce the sintering and coking of the active Ni sites, which enhanced the longevity of the catalyst. Raman analysis of the catalysts recovered after CDM experiments revealed that doping of Cu to Ni/MCM-41 enhanced the graphitic carbon deposition over the catalyst. All of the samples (Ni and Ni Cu-modified MCM-41) were characterized by H-2 chemisorption, SEM/TEM, XPS, XRD, H-2-TPR, N2O titration, and Raman spectroscopy to examine the bulk and surface properties of the catalysts.