Co-doped CuO/Visible Light Synergistic Activation of PMS for Degradation of Rhodamine B and Its Mechanism

doi:10.15541/jim20210090

Abstract

Abstract:

Elemental doping is an important method for improving the efficiency of catalysts. In this study, cobalt-doped CuO catalysts were prepared using a rapid precipitation method for the effective degradation of organic pollutants by photo-assisted activation of potassium peroxymonosulfate (PMS). The Co-doped CuO catalyst demonstrated degradation efficiency as high as 96% within 20 min reaction under visible light conditions, which is much higher than that of the undoped CuO. Cobalt doping transformed copper oxide nanoparticles from a three-dimensional needle-shape structure to a near-two-dimensional thin ribbon-like structure. Cobalt doping increases the flat-band potential of CuO and thus enhances the charge transfer efficiency. Furthermore, the effects of solution pH, initial dye concentration and catalyst dosage on the degradation efficiency were also investigated. XPS and EPR results show that cobalt doping can increase the oxygen vacancy content in CuO and thus improves the activation properties. The result of the trapping agent experiments indicates that main active species in the reaction are holes, while hydroxyl radicals, singlet oxygen, superoxide radicals and sulfate radicals are also involved. Finally, the reaction mechanism for the photo-assisted Co-doped CuO activated PMS degradation of RhB are generally proposed.

Key words: dye degradation, cobalt doping, potassium peroxymonosulfate, CuO

CLC Number:

TQ034

LAN Qing, SUN Shengrui, WU Ping, YANG Qingfeng, LIU Yangqiao. Co-doped CuO/Visible Light Synergistic Activation of PMS for Degradation of Rhodamine B and Its Mechanism[J]. Journal of Inorganic Materials, 2021, 36(11): 1171-1177.

Figures/Tables 9

Fig. 1 XRD patterns of CuO-S and Co-doped CuO

Fig. 2 SEM images of CuO-S (a) and Co-doped CuO (b) catalysts

Fig. 3 Comparison of the catalytic performance of Co-doped CuO and CuO-S under visible light illumination (PMS concentration=0.4 g/L; Initial RhB concentration=25 mg/L, catalyst dosage=0.4 g/L)

Fig. 4 Influences of catalyst dosage (a), initial dye concentration (b), solution pH (c) on catalytic performance, the recycling experiment results (d)

Fig. 5 Electrochemical impedance spectra (a), photocurrent(inset showing Mott-Schottky) curves (b), Diffuse reflection spectra (c), Zeta potential curves (d) of CuO-S and Co-doped CuO

Fig. 6 Comparation of XPS spectra of Co-doped CuO before and after reaction (Co2p (a), Cu2p (b), O1s (c)) XPS spectra of catalysts Co-doped CuO and CuO-S before reaction(O1s (d), Cu2p (e))

Fig. 7 EPR spectra of CuO-S and Co-doped CuO

Fig. 8 Free radical capture experiments of Co-doped CuO

Fig. 9 Proposed reaction mechanism for photo-assisted Co-doped CuO activated PMS degradation

References 21

[1]	BABUPONNUSAMI A, MUTHUKUMAR K. A review on Fenton and improvements to the Fenton process for wastewater treatment. Journal of Environmental Chemical Engineering, 2014, 2:557-572. DOI URL
[2]	GHANBARI F, MORADI M. Application of peroxymonosulfate and its activation methods for degradation of environmental organic pollutants: Review. Chemical Engineering Journal, 2017, 310:41-62. DOI URL
[3]	NIDHEESH P V, GANDHIMATHI R, RAMESH S T. Degradation of dyes from aqueous solution by Fenton processes: a review. Environmental Science and Pollution Research, 2013, 20:2099-2132. DOI URL
[4]	CHI F, SONG B, YANG B, et al. Activation of peroxymonosulfate by BiFeO₃ microspheres under visible light irradiation for decomposition of organic pollutants. RSC Advances, 2015, 5:67412-67417. DOI URL
[5]	PHAM H H, YOU S J, WANG Y F, et al. Activation of potassium peroxymonosulfate for rhodamine B photocatalytic degradation over visible-light-driven conjugated polyvinyl chloride/Bi₂O₃ hybrid structure. Sustainable Chemistry and Pharmacy, 2021, 19:100367-100376. DOI URL
[6]	YAN J F, LI J, PENG J L, et al. Efficient degradation of sulfamethoxazole by the CuO@Al₂O₃(EPC) coupled PMS system: optimization, degradation pathways and toxicity evaluation. Chemical Engineering Journal, 2019, 359:1097-1110. DOI URL
[7]	WANG J L, WANG S Z. Activation of persulfate (PS) and peroxymonosulfate (PMS) and application for the degradation of emerging contaminants. Chemical Engineering Journal, 2018, 334:1502-1517. DOI URL
[8]	PENG C, WEI P, LI X Y, et al. High efficiency photocatalytic hydrogen production over ternary Cu/TiO₂@Ti₃C₂T_x enabled by low-work-function 2D titanium carbide. Nano Energy, 2018, 53:97-107. DOI URL
[9]	VILLANI M, ALABI A B, ZAPPETTINI A, et al. Facile synthesis of hierarchical CuO nanostructures with enhanced photocatalytic activity. Crystal Research& Technology, 2014, 49:594-598.
[10]	YANG Z Y, DAI D J, YAO Y Y, et al. Extremely enhanced generation of reactive oxygen species for oxidation of pollutants from peroxymonosulfate induced by a supported copper oxide catalyst. Chemical Engineering Journal, 2017, 322:546-555. DOI URL
[11]	SUN M Y, LEI Y, CHENG H, et al. Mg doped CuO-Fe₂O₃ composites activated by persulfate as highly active heterogeneous catalysts for the degradation of organic pollutants. Journal of Alloys and Compounds, 2020, 825:154036-154044. DOI URL
[12]	WANG S X, TIAN J Y, WANG Q, et al. Development of CuO coated ceramic hollow fiber membrane for peroxymonosulfate activation: a highly efficient singlet oxygen-dominated oxidation process for bisphenol a degradation. Applied Catalysis B: Environmental, 2019, 256:117783-117793. DOI URL
[13]	YANG Q J, CHOI H, DIONYSIOU D D, et al. Iron-cobalt mixed oxide nanocatalysts: heterogeneous peroxymonosulfate activation, cobalt leaching, and ferromagnetic properties for environmental applications. Applied Catalysis B: Environmental, 2009, 88:462-469. DOI URL
[14]	KHAN A, LIAO Z W, LIU Y, et al. Synergistic degradation of phenols using peroxymonosulfate activated by CuO-Co₃O₄@MnO₂. Journal of Hazardous Materials, 2017, 329:262-271. DOI URL
[15]	DONG Q, QIAO N, LIU Y H. Spongelike porous CuO as an efficient peroxymonosulfate activator for degradation of Acid Orange 7. Applied Surface Science, 2020, 202:25-34.
[16]	LIU Y, GUO H G, ZHANG Y L, et al. Activation of peroxymonosulfate by BiVO₄ under visible light for degradation of Rhodamine B. Chemical Physics Letters, 2016, 653:101-107. DOI URL
[17]	KUSHWAHA A, MOAKHAR R S, DALAPATI G K, et al. Morphologically tailored CuO photocathode using aqueous solution technique for enhanced visible light driven water splitting. Journal of Photochemistry and Photobiology A: Chemistry, 2017, 337:54-61. DOI URL
[18]	LEE P Y, CHANG S P, CHANG S J. Photoelectrochemical characterization of n-type and p-type thin-film nanocrystalline Cu₂ZnSnSe₄ photocathodes. Journal of Environmental Chemical Engineering, 2015, 3:297-303. DOI URL
[19]	LUO X S, LIANG H, QU F S, et al. Free-standing hierarchical a-MnO₂@CuO membrane for catalytic filtration degradation of organic pollutants. Chemosphere, 2018, 200:237-247. DOI URL
[20]	JURISTIĆ A B, Choy W C H, ROY V A L. Photoluminescence and electron paramagnetic resonance of ZnO tetrapod structures. Adv. Funct. Mater., 2004, 14:856-864. DOI URL
[21]	MORAZONNI F, SCOTTI R, NOLA D P, et al. Electron paramagnetic resonance study of the interaction of the ZnO surface with air and air-reducing gas mixtures. J. Chem. Soc., Faraday Trans., 1992, 88:1691-1694. DOI URL