Fe/MCSAC catalysts surface modified with nitrogen DBD non‐thermal plasma for carbonyl sulfide catalytic hydrolysis activity enhancement

Abstract

The removal of carbonyl sulfide (COS or S=C=O) from gas streams over Fe/microwave coconut-shell activated carbon (MCSAC) catalysts modified by dielectric barrier discharge non-thermal plasma (NTP) were investigated. The properties of Fe/MCSAC catalysts modified by NTP in different conditions, included kinds of reactors, treatment times and input voltages. The surface properties were evaluated by means of energy-dispersive X-ray spectrometry, Brunauer Emmett Teller, X-ray photoelectron spectroscopy methods and theoretical calculation, which could help us understand the effects of the plasma treatment. The experiments results showed that the COS hydrolysis activities of Fe/MCSAC catalysts were largely enhanced after NTP modification. And the optimal reactor type, treatment time and input voltage were plate-plate type, 10 min and 35 V, respectively. The catalytic activity enhanced effectually due to the improvement of active component's dispersion after NTP modification. In addition, the extended oxygen functional groups on NTP-modified catalyst's surface could contribute to a higher activity for COS catalytic hydrolysis at low temperature. The investigation results indicate that non-thermal plasma treatment is an effective way to manipulate catalyst surface properties for COS catalytic hydrolysis reaction.

An overview of low‐temperature plasma surface modification of carbon materials for removal of pollutants from liquid and gas phases

“…Plasma treatment can also increase the external surface area of the carbon‐based catalyst, which is beneficial for improving surface mass transfer and surface reaction rates. [ 161 ] At the same time, the inner K atoms of catalysts can be excited to the catalyst surface by the sputtering effect, [ 162 ] which can improve the catalytic function of the catalyst toward various harmful gases (e.g., CS 2 , [ 163 ] COS, [ 161 ] and H 2 S [ 86 ] ).…”

“…However, insufficient improvements in some catalytic properties (e.g., stability) are achieved when the metal element is directly loaded on the CM surface using a physical method (e.g., the sol–gel method). However, plasma treatment can improve the dispersion of the active components (e.g., metal), [ 161,163 ] which allows the high SSA to be fully utilized. Simultaneously, the etching effect can cause large particles to be broken into smaller particles, causing some ultrafine particles to become embedded in the channels of the catalyst.…”