Ordered Mesoporous Cobalt Containing Perovskite as a High-Performance Heterogeneous Catalyst in Activation of Peroxymonosulfate

Abstract

An ordered mesoporous perovskite, La2CoMnO6−δ (MLCMO), was synthesized for the first time using a facile method of evaporation-induced self-assembly. The N2-sorption, scanning electron microscopy, and transmission electron microscopy measurements indicated that the optimized MLCMO possessed a high specific surface area (58.7 m2/g) and was uniformly mesoporous (11.6 nm). The MLCMO exhibited superior catalytic performance in peroxymonosulfate (PMS) activation for atrazine (ATZ) degradation. From a comparison view, the catalytic activity of the mesoporous MLCMO outperformed that of the bulk La2CoMnO6−δ (LCMO) and other common PMS activators, including α-MnO2, Co3O4, and CoFe2O4. The mechanisms of PMS activation by the MLCMO were investigated by X-ray photoelectron spectroscopy, electron spin resonance, and quenching tests. SO4 •–, •OH, 1O2, and O2 •– were identified as main reactive oxygen species generated from PMS activation. The Co and Mn in MLCMO were the active sites responsible for active radical generation. The lattice oxygen reversible redox sites (OL –/OL 2–), which were involved in the electron transfer of the MnIII/MnIV cycle, were demonstrated as redox partners to the cation active sites. In addition, the SO4 •–/•OH radical conversion was promoted at pH 11, which accelerated the consumption of PMS and seriously inhibited the degradation of ATZ.

A Resol‐Assisted Cationic Coordinative Co‐assembly Approach to Mesoporous ABO3 Perovskite Oxides with Rich Oxygen Vacancy for Enhanced Hydrogenation of Furfural to Furfuryl Alcohol

“…The amount of vacancy oxygen species characterized by peak area integration of O 1s are 43.7 % of O V ‐rich meso‐LMO and 45.5 % of O V ‐rich bulk LMO higher than 22.9 % of meso‐LMO and 19.3 % of bulk LMO, respectively (detailed data in the Supporting Information, Figure S4 and Table S2), which verifies that the prepared LMO samples can obtained increased concentration of oxygen vacancies after NaBH 4 treatment of meso‐LMO and bulk LMO [10, 43] . The divided Mn 2p 3/2 peaks at 641.7 eV and 642.7 eV were ascribed to Mn 3+ and Mn 4+ , respectively [8] . As seen from Figure 3 b and the Supporting Information, Table S3, the relative content of Mn 3+ grow from 16.4 % of bulk LMO to 29.5 % of meso‐LMO and 34.5 % of Ov‐rich meso‐LMO, showing an increasing trend along with the enhanced concentration of oxygen vacancies, which can be attributed to electron transfer induced by the formation of oxygen vacancy [8, 44] .…”

“…The divided Mn 2p 3/2 peaks at 641.7 eV and 642.7 eV were ascribed to Mn 3+ and Mn 4+ , respectively [8] . As seen from Figure 3 b and the Supporting Information, Table S3, the relative content of Mn 3+ grow from 16.4 % of bulk LMO to 29.5 % of meso‐LMO and 34.5 % of Ov‐rich meso‐LMO, showing an increasing trend along with the enhanced concentration of oxygen vacancies, which can be attributed to electron transfer induced by the formation of oxygen vacancy [8, 44] . Figure 3 c shows the temperature‐programmed desorption of O 2 (O 2 ‐TPD) spectra of LMO samples, in which vacancy oxygen species and their content are presented by the integration of different peaks and the detailed data are summarized in the Supporting Information, Table S4.…”

“…Perovskite oxides have emerged as promising catalysts in various catalytic application due to their low cost, high abundance, and considerable activity and durability [1–4] . The crystal structure composition as well as surface chemical property of perovskite oxides are flexible, thus enabling their nature to be tailored preferably for targeting catalytic reactions [5–8] . As a powerful method, oxygen vacancy engineering has been developed to regulate electronic structure and surface chemical property of perovskite oxides and consequently enhance their catalytic performance [9–12] .…”

“…[1][2][3][4] The crystal structure composition as well as surface chemical property of perovskite oxides are flexible,thus enabling their nature to be tailored preferably for targeting catalytic reactions. [5][6][7][8] As ap owerful method, oxygen vacancy engineering has been developed to regulate electronic structure and surface chemical property of perovskite oxides and consequently enhance their catalytic performance. [9][10][11][12] For instance,t he modified perovskite oxide La 0.8 Sr 0.2 CoO 3 with surface oxygen defects and surface Lewis acid sites was served as ac atalyst to effectively improve the activity of propane oxidation.…”

A Resol‐Assisted Cationic Coordinative Co‐assembly Approach to Mesoporous ABO3 Perovskite Oxides with Rich Oxygen Vacancy for Enhanced Hydrogenation of Furfural to Furfuryl Alcohol

“…[10,43] Thed ivided Mn 2p 3/2 peaks at 641.7 eV and 642.7 eV were ascribed to Mn 3+ and Mn 4+ ,r espectively. [8] As seen from Figure 3b and the Supporting Information, Table S3, the relative content of Mn 3+ grow from 16.4 %ofbulk LMO to 29.5 %ofmeso-LMO and 34.5 %o fO v-rich meso-LMO,s howing an increasing trend along with the enhanced concentration of oxygen vacancies,w hich can be attributed to electron transfer induced by the formation of oxygen vacancy. [8,44] Figure 3c shows the temperature-programmed desorption of O 2 (O 2 -TPD) spectra of LMO samples,i nw hich vacancy oxygen species and their content are presented by the integration of different peaks and the detailed data are summarized in the Supporting Information, Table S4.…”