Ammonia decomposition on a highly-dispersed carbon-embedded iron catalyst derived from Fe-BTC: stable and high performance at relatively low temperatures

Abstract

Fe-BTC (iron 1,3,5-benzenetricarboxylic acid), a commercially available metal organic framework (MOF), was used as a sacrificial template to produce a series of carbon-embedded Fe catalysts upon its pyrolysis at different temperatures. The catalyst prepared by pyrolyzing Fe-BTC at 400 degrees C under flowing N-2 provided a high graphitic degree on the carbon support hosting highly dispersed Fe species at a Fe loading of 34 wt%. Performance measurements on ammonia decomposition to produce COx-free hydrogen showed that this catalyst provided an ammonia conversion of 73.8% at a space velocity of 6000 cm(3) NH3 h(-1) g(cat)(-1) and at 500 degrees C for at least 120 h. This stable performance, exceeding that of some of the best non-noble metal catalysts, was associated with the presence of highly-dispersed Fe species at a significantly high Fe loading, embedded in a carbonaceous shell. The presence of the carbonaceous shell not only protected the active species against sintering, but also made them electron rich owing to its high level of graphitization.