Plasma Regeneration of Spent Pd/Al₂O₃ Catalysts and Their Electrochemical Performance

Abstract

A dielectric barrier discharge (DBD) plasma was applied to reactivate palladium on alumina (Pd/Al 2 O 3 ) waste catalysts at extreme conditions, addressing a common problem of reusing the spent catalysts instead of discarding them. Experimental studies of the effect of gas composition in the plasma process reveal different extent of coke elimination and different electrochemical performance of the reactivated Pd/Al 2 O 3 catalysts, ranked as Artreated > N 2 -treated > O 2 -treated > untreated spent catalyst at fixed gas flow rate and regeneration time. The effect of the regeneration time and gas flow rate on the electrochemical performance of the reactivated Pd/Al 2 O 3 catalysts was systematically studied. The results show that for Ar and N 2 process gas, the electrochemical performance of the plasma-treated spent catalyst is improved with the increase of the gas flow rate and the treatment time. However, if O 2 is used, then the electrochemical performance of the spent catalyst decreases with the increase of the gas flow rate and the treatment time. The XPS results show that higher oxidation degrees of Pd reduces the electrochemical performance. This study demonstrates a new strategy for reusing the otherwise waste catalyst in a simple and environment-benign solvent-free manner.

Advances in morphology-controlled alumina and its supported Pd catalysts: synthesis and applications

“…, due to their numerous advantages. 16–21 The suitable reducibility and oxidizability of Pd species lead to an adjustable valence state. The Pd 0 species have an excellent ability to activate and dissociate hydrogen molecules, while the Pd δ + (0 < δ ≤ 4) species show a unique ability to activate oxygen molecules, thus dictating the exceptional catalytic performance for most hydrogenation and oxidation reactions.…”

Fluorescent Patterning of Polymeric Substrates with Rare-Earth-Doped Nanophosphors Assisted by Atmospheric Pressure Plasma

“…Such a configuration prevents the formation of electric arcs and allows homogeneous discharges in the electrode gap. DBD plasmas have been applied in many applications, like surface treatment, nanomaterials synthesis, pollutant degradation, plasma catalysis, and gas conversion. , The high concentration of active species produced in the plasma medium can help to accelerate chemical reactions or to promote reactions that are difficult to achieve in a traditional chemical process . At the same time, owing to its atmospheric pressure and nonequilibrium characteristics, DBD plasma printing is especially favorable for handling temperature-sensitive substrates or coatings in a mild environment without destroying them .…”

Virtual Special Issue on Chemical Engineering under Extreme Conditions

“…Herein, our researchers break the boundaries of standard operating conditions, into the realms of unknown phenomena at extreme temperatures, pressures, acidities, and electromagnetism. I&EC Research has a long history of exploring the extremes, from our first paper in 1963 developing lubricants for liquid fuel-powered missiles, to our latest papers on plasma catalysts in high-voltage environments. − We hope this issue inspires you to turn up the dial on your own research and discover new properties and applications in chemical engineering.…”

“…Plasma is the most extreme state of matter: a soup of charged particles, active species in excited states, and reactive radicals . It is no surprise then that our plasma researchers have submitted their latest findings to this VSI, using plasma to upcycle plastic waste, regenerate waste catalysts, and convert CO 2 to CH 4 or CO and O 2 . , …”