Reactivity of carbon spheres templated Ce/LaCo0.5Cu0.5O3 in the microwave induced H2O2 catalytic degradation of salicylic acid: Characterization, kinetic and mechanism studies

• Published in: Journal of colloid and interface science 2020-08, Vol.574, p.74-86
• Main Authors: Wang, Yin, Yu, Lan, Wang, Ruotong, Wang, Yun, Zhang, Xiaodong
• Format: Article
• Language: English
• Subjects: 3D meso-macroporous structure; Ce doped perovskite; Degradation mechanism; MW-induced H2O2 catalysis; Salicylic acid
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2020.04.042

[Display omitted] •10Ce/LCCO@CS exhibited superior catalytic activity in MW induced H2O2 catalytic (MIHC) process.•·OH generated by MW excited electron-hole pairs act as predominant radicals in the MIHC process.•Doping with Ce oxides enhance the ·OH generation and catalytic activity of 10Ce/LCCO@CS.•The cycles of Co3+/Co3+, Cu2+/Cu+ and Ce4+/Ce3+ are involved in the catalytic oxidation process. Three-dimensionally (3D) meso-macroporous LaCo0.5Cu0.5O3-supported Ce (xCe/LCCO; x = 0–15 wt%) were prepared by in-situ carbon spheres-templating strategy. Structural and physicochemical properties of the materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and vector network analysis (VNA), and their microwave (MW) catalytic activities towards salicylic acid (SA) degradation were evaluated. It was found that appropriate Ce doping amount (x = 10 wt%) was beneficial for the generation of high-quality 3D meso-macroporous structure, good MW absorbing ability, high active oxygen species concentration and strong interaction between Ce and carbon spheres templated LaCo0.5Cu0.5O3, resulting in the high MW catalytic activity. Significantly, SA degradation efficiency reached 93.8% under optimal conditions with initial pH of 6.0, MW power of 480 W, catalyst dosage of 6.0 g·L−1, H2O2 concentration of 2 mL·L−1 and SA concentration of 10 mg·L−1. The obtained kinetic equation followed the pseudo-first-order model. Radical scavenger measurements indicated that ·OH produced during catalytic degradation process was the dominant active radical. Furthermore, Co, Cu and Ce species were involved in the generation of ·OH, which were responsible to the excellent performance of the catalyst/MW/H2O2 system. The catalyst also showed good reusability and stability. Hence, the catalyst/MW/H2O2 technology has potential application for the degradation of organic pollutants in wastewater.