The role of carbon surface chemistry in N 2O conversion to N 2 over Ni catalyst supported on activated carbon

Abstract

The effect of acidic treatments on N 2O reduction over Ni catalysts supported on activated carbon was systematically studied. The catalysts were characterized by N 2 adsorption, mass titration, temperature-programmed desorption (TPD), and X-ray photoelectron spectrometry (XPS). It is found that surface chemistry plays an important role in N 2O-carbon reaction catalyzed by Ni catalyst. HNO 3 treatment produces more active acidic surface groups such as carboxyl and lactone, resulting in a more uniform catalyst dispersion and higher catalytic activity. However, HCl treatment decreases active acidic groups and increases the inactive groups, playing an opposite role in the catalyst dispersion and catalytic activity. A thorough discussion of the mechanism of the N 2O catalytic reduction is made based upon results from isothermal reactions, temperature-programmed reactions (TPR) and characterization of catalysts. The effect of acidic treatment on pore structure is also discussed.