Non-isothermal reduction kinetics and reducibilities of nickel and cobalt faujasites

Abstract

The temperature-programmed (5 K min^–1) reduction of nickel and cobalt faujasites having different Si/Al ratios has been studied in a closed-circuit apparatus. Both hydrogen and a mixture of hydrogen and carbon monoxide (H₂/CO = 22.8) were used as reducing media in the pressure range 10–50 kPa and the temperature range 300–1100 K. The non-isothermal kinetics may be described adequately by setting up a second-order reaction rate equation. Relative reducibilities are defined by the temperatures of the peak maxima in the t.p.r. spectra and are related to the acidities of the zeolites.