SrCo1−xTixO3−δ perovskites as excellent catalysts for fast degradation of water contaminants in neutral and alkaline solutions

Abstract

Perovskite-like oxides SrCo1−xTixO3−δ (SCTx, x = 0.1, 0.2, 0.4, 0.6) were used as heterogeneous catalysts to activate peroxymonosulfate (PMS) for phenol degradation under a wide pH range, exhibiting more rapid phenol oxidation than Co3O4 and TiO2. The SCT0.4/PMS system produced a high activity at increased initial pH, achieving optimized performance at pH ≥ 7 in terms of total organic carbon removal, the minimum Co leaching and good catalytic stability. Kinetic studies showed that the phenol oxidation kinetics on SCT0.4/PMS system followed the pseudo-zero order kinetics and the rate on SCT0.4/PMS system decreased with increasing initial phenol concentration, decreased PMS amount, catalyst loading and solution temperature. Quenching tests using ethanol and tert-butyl alcohol demonstrated sulfate and hydroxyl radicals for phenol oxidation. This investigation suggested promising heterogeneous catalysts for organic oxidation with PMS, showing a breakthrough in the barriers of metal leaching, acidic pH, and low efficiency of heterogeneous catalysis.

Superior three‐dimensional perovskite catalyst for catalytic oxidation

“…Secondly, the basic solution is beneficial to the redox cycle of Co 3+ /Co 2+ , which promotes the catalytic reaction. 4,5,[7][8][9][10]13,[29][30][31][32] It is also worth mentioning that the alkaline condition is capable of stabilizing the surficial chemistry of perovskite oxide, and suppressing metal leaching, which may allow the catalysts to keep a relatively high activity during the whole degradation process. In addition to the PH values, the temperature is another important factor that may affect MB degradation rate.…”

“…This may indicate the activity of Co 2+ /Co 3+ redox couple (LSC-Co(II)/ LSC-Co(III)) in catalyzing the pollutant oxidation in the presence of PMS. The HR-XPS spectrum of O 1s was further deconvoluted into four sub peaks ( Figure 4J) [2][3][4][5][6][7][8][9][10]37 The enhancement on sub peak of "H 2 O or CO 3 2-" (Table S7) indicates that little carbonates may be generated during the complex adsorption process of pollutant or recycling test via AOP which involves the generation of carbon-based intermediates. Thus, the carbonate adsorbed on the surface of this 3D hollow fiber catalyst may cause the deactivation.…”

“…4 Recently, lots of perovskite oxides as catalysts toward wastewater treatment have been paid increasing attention because of their special physicochemical properties. 4,[7][8][9][10][11][12][13][14][15] However, the issue of inevitable (metal) element leaching hampers the future application of these metal contained catalysts. Engineering approaches to wastewater treatment must aim for improving the stability and efficiency of catalysts.…”

Fine‐Tuning Surface Properties of Perovskites via Nanocompositing with Inert Oxide toward Developing Superior Catalysts for Advanced Oxidation

“…Synthesis of Catalysts : In a typical synthesis of LaFeO 3 –La 2 O 3 nanocomposites with the nominal compositions of La 1+ x FeO 3 ( x = 0, 0.1, 0.15, and 0.2) perovskites by the one‐pot sol–gel method, stoichiometric amounts of La(NO 3 ) 3 ⋅ 6H 2 O and Fe(NO 3 ) 3 ⋅ 9H 2 O powders, according to the nominal compositions, were dissolved in deionized water to form a mixed solution. EDTA and CA were used as the complexing agents and added sequentially for total metals:EDTA:CA at a fixed molar ratio of 1:1:2.…”

Recent Advances in Novel Nanostructuring Methods of Perovskite Electrocatalysts for Energy‐Related Applications

“…Moreover, a variety of perovskite derivatives including double perovskite, layered perovskite, quadruple perovskite, and others add to the diversity of the perovskite family. Such flexibility in composition and structure gives rise to the tunable electronic structure of perovskites, exhibiting diverse physical and chemical properties that can meet the need of a myriad of applications, such as heterogeneous catalysis, photocatalysis, wastewater treatment, oxygen permeation membranes, supercapacitors, and sensors . Until recently, their applications toward electrocatalysis have attracted growing attention worldwide.…”