Z-scheme plasma-catalysis using Ru-doped CeO2/Bi2O3 for efficient GenX degradation via oxygen vacancy engineering

Abstract

Herein, GenX, a substitution chemical for perfluorooctanoic acid (PFOA) was degraded using argon (Ar) jet plasma combined with ruthenium doped cerium oxide/bismuth oxide composite (CeO2/Bi2O3, CBO). As a result, GenX removal using 0.1% Ru-doped CBO [Ru (0.1%)-CBO] in plasma system achieved up to 74% degradation performance in 30 min, 1.7-folded higher than that of sole plasma. The GenX removal kinetic rates showed strong correlations with the concentration of OV and the (1 1 1) facet, identifying them as key factors in GenX removal. The contribution analysis of the reactive species revealed that hydroxyl radical (center dot OH) and singlet oxygen (1O2) were important for the GenX degradation in both plasma and plasma-catalysis. In-situ X-ray photoelectron spectroscopy (XPS) and surface-enhanced-Raman spectroscopy (SERS) analyses revealed a clear electron transfer pathway of Ru (0.1%)-CBO from CeO2 to Bi2O3 and finally to RuO2, confirming a Z-scheme mechanism facilitated by RuO2 acting as an electron sink. The combination of argon jet plasma with Ru (0.1%)-CBO significantly enhanced energy efficiency, reducing the electrical energy per order (EEO) from 295.8 to 149.7 kWh m-3 for GenX degradation. Overall, Ru (0.1%)-CBO demonstrates high catalytic stability and energy efficiency, offering a promising strategy for PFAS remediation.