Steam reforming of methane on nickel aluminate defined structures with high Al/Ni ratio

摘要

A series of several defined structures Ni_xAl_yO_z with an atomic ratio Al/Ni from 9 to 32 (Ni2Al_(18)O_(29) ,NiAl_(10)O_(16), NiAl_(26)O_(40) and NiAl_(32)O_(49)) (wt %Ni from 10.9 to 3.4) were prepared by the method of the liquid precursor and calcined at 900°Cduring 4 hours. The catalysts were characterized by XRD, TEM, BET and TPR. By XRD, all the phases expected have been obtained, however, for all the catalysts, the characteristic main phase is often mixed with minors phases (e.g NiAl_(32)O_(49)). For NiAl_(26)O_(40) and NiAl_(32)O_(49), the characterised minor phases are NiAl_(10)O_(16) and Ni2Al_(18)O_(29). By TPR, reduction of all the catalysts into Ni° and formation of Al2O3 occur at high temperatures (between 825 and 875°C).TEM shows Ni particles finely dispersed (<10nm). The defined structures, after reduction at high temperature (800°C, lh) under hydrogen atmosphere were successfully tested in steam reforming of methane.