Atomically dispersed Ru-O3 anchored on the Ti3C2Tx surface with multiple reaction sites for the selective generation of single oxygen via peroxymonosulfate activation

Abstract

Singlet oxygen (¹O₂) is an electrophilic oxidant capable of selectively eliminating contaminants in complex wastewater, which is highly expected in environmental remediation. However, due to the limitations in synthesizing catalysts with well-defined adsorption and active sites, the efficient and selective generation of ¹O₂ remains challenging. Herein, isolated Ru-O₃ moiety decorated two-dimensional Ti₃C₂T_x catalysts (Ru-SA/Ti₃C₂T_x) were prepared to regulate ¹O₂ generation via peroxymonosulfate (PMS) activation. The constructed catalysts with asymmetric dual-metal structures (Ti-O-Ru) exhibited surprising mass activity of 1.4 × 10⁴ min⁻¹·mol⁻¹ with a high ¹O₂ generation selectivity of 98.3 %. Mechanism inquiry indicated that the enhanced adsorption and electron transfer between PMS and Ru-SA/Ti₃C₂T_x attributed to the synergistic effect of the strong adsorption at the Ru sites and the rapid electron transfer in the asymmetric Ti-O-Ru structures. Theoretical calculations demonstrated that Ru-O₃ moiety decreased the formation energy barrier of key intermediate *O, thus converting to a ¹O₂-dominated oxidation path. Two possible degradation pathways of tetracycline hydrochloride (TCH) were proposed by gas chromatography-mass spectrometry (GC–MS), and the toxicities of intermediates were significantly decreased due to the strong electrophilic attack of ¹O₂. This study deepened the understanding of the specific contribution of individual sites in multi-site synergistic, which furnished implications for the design and optimization of Fenton-like catalysts.