Effect of heating method on NOx decomposition on H3PW12O40•6H2O

Abstract

The thermal decomposition of nitrogen oxides (NO_x) on phosphotungstic acid (H₃PW₁₂O₄₀·6H₂O or HPW) by two different heating methods is compared. Infra-red (IR) and X-ray diffraction (XRD) measurements are conducted to investigate the decomposition mechanism. Both heating methods, i.e. heating from 30 °C to 450 °C at a rate of 150 °C/min (“rapid heating”) and heating at a constant temperature of 450 °C (“constant-temperature heating”) lead to an actual, considerably high heating rate. Compared with rapid heating, however, constant-temperature heating results in enhanced N₂ conversion (21.8%). Furthermore, the catalyst can be reused after decomposition at constant-temperature heating, while its performance quickly degrades after decomposition via rapid heating.

KEY WORDS: Nitrogen oxides, Heteropoly acids, Decomposition, Heating

Bull. Chem. Soc. Ethiop. 2013, 27(2), 281-287.

DOI: http://dx.doi.org/10.4314/bcse.v27i2.13