Intensification of catalytic reaction of nitrous oxide decomposition into a replaceable wall-coated microreactor using electrophoretic deposition method

Abstract

The novel replaceable wall-coated micro-reactor has been introduced to eliminate the hazardous nitrous oxide by utilizing the direct catalytic decomposition method. The commercial Pd/ γ-Al2O3 catalyst (containing 0.5 wt.% Pd) is coated on SUS304 stainless steel microchannels walls by using electrophoretic deposition (EPD) and then investigated at the temperature range of 300-400 °C. The main scope of this study is to define the optimum parameters affecting EPD such as deposition time, electrophoretic voltage, and solvent as the suspension media to reach the complete decomposition of nitrous oxide. The catalytic activity of the coated microchannels is verified at various gas hourly space velocities (GHSV). The nitrous oxide decomposition is enhanced 300% by raising the deposition time from 1 minute to 3 minutes and then remarkably is declined 80% at times higher than 3 minutes. The optimum electrophoretic deposition parameters including deposition time of 3 minutes at the voltage of 120 V in the range of 30-160 V and isopropanol as the solvent, resulting in 100% decomposition of nitrous oxide at 400 °C and GHSV of 1000 mL h−1 g−1cat . Moreover, the performance of the wall-coated micro-reactor at optimum EPD conditions compared to the equivalent packed-bed reactor caused 40% improvement in nitrous oxide decomposition and its energy consumption is 33.3% lower than packed-bed reactor for equal N2O decomposition.