Lollipop-shaped interconnected MnO2 nanotube/Co3O4 polyhedron composite derived from zeolitic-imidazolate framework-67 as an efficient electrocatalyst for oxygen evolution reaction. (December 2022)

• Record Type: Journal Article
• Authors: Kale, Vaibhav Namdev; Maiyalagan, T.
• Is Part Of: Materials today chemistry. Volume 26(2022)
• Publication Date: 2022-12
• Subjects: Precious metal-free electrocatalyst -- ZIF-67 -- Onset potential -- OER; Chemistry -- Periodicals; Materials -- Research -- Periodicals; Materials science -- Periodicals; Chemistry; Materials -- Research; Electronic journals; Periodicals; 660.282
• DOI: 10.1016/j.mtchem.2022.101063
• Languages: English
• ISSNs: 2468-5194

Abstract

Abstract: The development of efficient electrocatalysts for the oxygen evolution reaction (OER) is of great importance to energy-related necessities. Currently, the fabrication of precious metal-free electrocatalysts for oxygen evolution reaction is a desirable and challenging task for the widespread application of water splitting. In this work, a novel lollipop-like MnO2 /Co3 O4 composite is prepared as an electrocatalyst for enhanced oxygen evolution reaction by using zeolitic-imidazolate framework (ZIF-67) template. The ZIF-67 is grown on the open end of MnO2 nanotube and the obtained MnO2 /ZIF-67 is then converted to MnO2 /Co3 O4 by simple calcination treatment under air atmosphere. The lollipop-like structure of the MnO2 /Co3 O4 composite was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterizations. The lollipop-like structure consists of MnO2 nanotube and porous Co3 O4 polyhedron that exhibited significant electrocatalytic activity with lowest onset potential (1.54 V vs. RHE), Tafel slope (69 mV/dec) and higher current density (84.9 mA/cm 2 ) compared with MnO2 /ZIF-67, Co3 O4 and MnO2 catalyst. Therefore, it is evident that the MnO2 /Co3 O4 composite possesses enhanced OER activity and shows good electrochemical stability in alkaline medium, which makes it an efficient precious metal-free electrocatalyst for oxygen evolution reaction. Graphical abstract: Image 1 Highlights: Lollipop-like MnO2 /Co3 O4 composite consists of MnO2 nanotubes and Co3 O4 polyhedrons was synthesized by using ZIF-67 template. The interconnected MnO2 /Co3 O4 highly favors the charge transport at the electrode interface that enhances the OER performance. The composite exhibits significant electrocatalytic activity with lowest onset potential and smaller Tafel slope. The excellent electrocatalytic performance of the composite is ascribed to the synergistic effect between Mn and Co oxides.