Ruthenium-doping tuned electronic structure and oxygen vacancy in self-supported cobalt spinel oxide nanosheet assemblies for efficient water purification

Co-based catalysts have demonstrated significant potential for degrading antibiotic contaminants through peroxymonosulfate (PMS) activation. However, difficulties in separation and high ion leaching rates inhibit practical application. Herein, we develop a stable and easily recyclable hybrid catalyst that integrates Ru-doped Co spinel oxide with nickel foam (Ru-Co 3 O 4 /NF) via electrodeposition and calcination. The incorporation of Ru effectively adjusts the molar ratio of Co 2+ to Co 3+ in Co 3 O 4 , resulting in an abundance of Co 2+ that efficiently activate PMS for tetracycline (TC) degradation. Under optimal conditions, Ru-Co 3 O 4 /NF achieves a TC removal rate of 96.6 % within 30 min and demonstrates broad degradation capabilities for various organic pollutants. The Ru-Co 3 O 4 /NF/PMS system operates effectively under diverse conditions, including the presence of inorganic ions and organic matter, as well as across different solution pH levels. Quenching experiments and electron paramagnetic resonance results indicate that the Ru-Co 3 O 4 /NF/PMS system involves both radical and non-radical pathways, with SO 4 •− playing a significant role. The degradation of TC follows three reaction pathways through fourteen intermediates. The toxicity of the original TC is significantly reduced following the degradation process. The present work presents a useful strategy to modulate the electronic structure of spinel oxide for activating PMS to eliminate organic pollutants.