Liquid-Phase Deposition Synthesis of ZIF-67-Derived Synthesis of Co3O4@TiO2 Composite for Efficient Electrochemical Water Splitting

Abstract

In this article, a novel Co3O4@TiO2 composite is synthesized by applying two-step methods. ZIF-67 is synthesized and used as a template for the synthesis of the composite. The composite is designed by using the effective photocatalytic properties of Co3O4 and TiO2. The resulting synthesized composite is supposed to offer superior properties compared to their counterparts. The synthesized Co3O4@TiO2 composite is characterized by powder X-ray diffraction (PXRD), Brunauer–Emmet–Teller (BET), atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical water splitting, including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) studies on the Co3O4@TiO2 composite, is evaluated by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) analysis in a 2M aqueous KOH electrolyte. The current generation stability of these samples is deliberated by chronoamperometric measurements. It is observed, from LSV results at a 1 mV/s scan rate, that metal oxides incorporated on other metal oxides have a higher current density and lower onset potential as compared to pure metal oxides. From the obtained results, it has become evident that synthesized studies on the Co3O4@TiO2 composite possess significant potential for electrochemical water splitting with the lowest onset potential, highest current density, better OER, and HER activity.

Photocatalytic and Electrocatalytic Properties of Cu-Loaded ZIF-67-Derivatized Bean Sprout-Like Co-TiO2/Ti Nanostructures

“…These are in good agreement with the literature for ZIF-67-derivatized catalysts and Co (and/or Ni) oxide-based catalysts [ 13 , 28 ]. On the basis of the onset potentials (E RHE ) from the LSV curves ( Figure 9 a), the OER overpotential (η) was calculated using η = E RHE −1.23 V [ 11 ]. The onset overpotential was then calculated to be between 340 mV and 430 mV.…”

“…Metal–organic frameworks (MOFs) including other materials have been extensively employed in diverse application areas such as environments, adsorbents, organic light emitting displays, sensors and catalysts [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Among diverse MOFs, the zeolitic imidazolate framework (ZIF) exhibits zeolite-like topologies where imidazolate linkers are connected with tetrahedrally coordinated transition metal ions such as Co and Zn [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. In this ZIF-class, ZIF-67 has Co-N tetrahedral coordination commonly synthesized with Co(II) precursor and 2-methylimidazole [ 5 , 6 , 7 , 8 , 9 , 10 ].…”

“…In this ZIF-class, ZIF-67 has Co-N tetrahedral coordination commonly synthesized with Co(II) precursor and 2-methylimidazole [ 5 , 6 , 7 , 8 , 9 , 10 ]. Many catalyst materials have been synthesized using ZIF-67 and examined in diverse areas of hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), CO 2 hydrogenation reaction, energy storage and toluene oxidation [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. For a synthetic strategy of Co 3 O 4 @TiO 2 composite, thermal decomposition of ZIF-67 followed by the liquid-phase deposition method was introduced [ 11 ].…”

“…Many catalyst materials have been synthesized using ZIF-67 and examined in diverse areas of hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), CO 2 hydrogenation reaction, energy storage and toluene oxidation [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. For a synthetic strategy of Co 3 O 4 @TiO 2 composite, thermal decomposition of ZIF-67 followed by the liquid-phase deposition method was introduced [ 11 ]. The catalyst showed an overpotential of 269 mV at 10 mA cm −2 and a Tafel slope of 106 mV/dec for OER test in 2 M KOH electrolyte, and an overpotential of 153 mV and a Tafel slope of 81 mV/dec in HER test, respectively.…”

“…As discussed in the literature, many strategies have been employed and the consequent materials have been tested in various application areas [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Motivated by this, we seek to further widen the synthesis of ZIP-derivatized catalyst materials and examine new physicochemical properties of a newly synthesized material.…”