Strategy for oxygen vacancy enriched CoMn spinel oxide catalyst activated peroxodisulfate for tetracycline degradation: process, mechanism, and toxicity analysis.

Antibiotic-like organic pollutants are harmful to aquatic ecosystems and seriously disrupt the ecological balance. Herein, we propose a simple and versatile method to prepare cobalt-manganese oxides with high specific surface area and abundant oxygen vacancies using low-temperature reduction crystallization, which greatly facilitates the adsorption and electron transfer between the catalyst, PDS, and TC, thus accelerating the degradation of tetracycline (TC). Among them, the degradation efficiency of TC in the CoMn2O4(C)/PDS system was 99.8% in 60 min and the degradation rate remained above 90% after four cycles. The possible degradation mechanism is also discussed, where Co is the main metal active center of the catalyst and Mn plays an auxiliary catalytic role to promote the generation of reactive radicals in PDS through redox interactions between Co and Mn, where SO4 -˙ is the main active species for TC degradation. Finally, the possible degradation pathways of TC are proposed and the toxicity of the intermediates is evaluated. Findings from this work will shed light on the rational design of bimetallic oxide catalysts.

Revealing the mechanism of high water resistant and excellent active of CuMn oxide catalyst derived from Bimetal-Organic framework for acetone catalytic oxidation.

Environmental H2O is an influential factor in the low-temperature catalytic oxidation of volatile organic compounds (VOCs), and it significantly impacts the reaction process and mechanism. Here, a series of rod-like Cu-Mn oxides were synthesised by pyrolysing Cu/Mn-BTC for acetone oxidation. The results confirm that the formation of multiphase interfaces have more excellent catalytic performance compared to single-phase catalysis. This phenomenon can be attributed to the formation of multiphase interfaces, which resulted in the synthesized catalysts with more active oxygen species and defective sites. The CuMn2Ox catalyst exhibited superior catalytic performance (T90 = 150 °C), high water resistance and long-term stability. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy and thermal desorption-gas chromatography-mass spectrometry results indicated that the degradation pathway of acetone was as follows: acetone ((CH3)2CO*) â†’ enolate complexes ((CH2) = C(CH3) O*) â†’ acetaldehyde ((CH3CHO*) â†’ acetate (CH3COO*) â†’ formate (HCOO*) â†’ CO2 and H2O. At a low-temperature, water vapour dissociated a large number of activated hydroxyl groups on the multiphase interface, which promoted the dissociation of enolate complexes and acetaldehyde species. This composite oxide is a promising catalyst for removing oxygenated VOCs at high humidity.