Investigating the impact of catalysts on N2 rotational and vibrational temperatures in low pressure plasmas

Abstract

Future application of plasma assisted catalysis (PAC) requires a thorough understanding of energy partitioning within the plasma-catalyst system. We have studied the impact of adding a catalyst (TiO2 and zeolites) on the plasma energetics within an N2 low-temperature, radio frequency (RF) plasma by measuring the vibrational and rotational temperatures of the gas-phase N2. The presence of either micro- or nano-structured materials (zeolite and TiO2 substrates, respectively) within the plasma significantly decreases N2 (g) vibrational temperature, suggesting these materials promote vibrational relaxation within the discharge upon interaction with a catalytic substrate. In addition to evaluating the spectroscopic characteristics of the N2 discharge, we have assessed material morphology and chemical composition before and after plasma exposure. The porous network of both TiO2 and zeolite substrates were maintained after plasma exposure, although small amounts of nitrogen incorporation occurred at the surface of both materials.