Porous ZnO/Co₃O₄ heteronanostructures derived from nano coordination polymers for enhanced gas sorption and visible light photocatalytic applications

Abstract

Porous ZnO/Co 3 O 4 heteronanostructures are successfully fabricated by a novel one-step solid state conversion of a novel [(Zn) x −(Co) 7-x (BDC) (DHS)].nH 2 O (x = 1, 3, 4, 6)] nano coordination polymers (NCPs). The precursor is prepared by one-pot wet chemical approach at room temperature without any surfactant using dihydroxy salophen ligand and 1,4-benzenedicarboxylic acid as the linkers in presence of 10 zinc (II) acetate and cobalt (II) acetate in DMF solvent. Different weight ratios of the Zn/Co are fabricated in-situ into the hetero-structures during the preparation of the NCPs to tune their physicochemical properties. The produced ZnO/Co 3 O 4 nanostructure possesses relatively higher surface area (80-140 m 2 /g) and having significant N 2 gas sorption capacity in comparison with reported materials. It is suggested that synergistic effect of each component, higher separation of electron and holes, high 15 surface area and porous structure led to the promising visible light photocatalytic properties. The prepared mixed metal oxides show significant reusability in photocatalysis more than five times without losing their properties. Importantly, the mixed-metal NCPs could be applied as an effective route to generate not only binary oxide, but also ternary or quaternary oxide nanostructures with desired morphology and enhanced physicochemical properties. 20 65 achieved by choosing appropriate NCP precursors with special morphologies and under suitable experimental conditions. Calcinations of these materials produce a large amount of gas due to the decomposition of the organic ligands, and a porous structure is formed, which retains the shape of the precursor. 19-21 70 Binary, ternary or quaternary transition metal oxides are traditionally synthesized in laboratory using high-temperature

Strategic Synthesis of SiO2-Modified Porous Co3O4Nano-Octahedra Through the Nanocoordination Polymer Route for Enhanced and Selective Sensing of H2Gas over NOx

“…The formation of Co­(II)-NCP occurred upon introduction of H 2 BDC into the reaction medium. The product obtained was centrifuged, washed with acetonitrile, and then dried at 60 °C for 3 h. We had followed a similar chemical synthesis of Co­(II) NCP (first step) as per a recent report from our lab . However, the previously executed method (pyrolysis or decomposition) does not favor formation of unique morphology of Co 3 O 4 .…”

Preparation Of ZnO/Co3O4 Hollow Microsphere By Pollen‐biological Template And Its Application In Photocatalytic Degradation

“…For ZnO/Co 3 O 4 composites, the narrow band gap structure of Co 3 O 4 can improve the utilization of visible light and achieve high charge transfer . As reported in the literatures, ZnO/Co 3 O 4 composites have been widely used in the fields of photocatalysis, electrode, adsorption, catalytic oxidation, etc, which exhibit many advantages; thus, it may be a promising catalyst for degradation of pollutants in waste water.…”

A p-n Heterojunction Based Pd/PdO@ZnO Organic Frameworks for High-Sensitivity Room-Temperature Formaldehyde Gas Sensor

“…On the other side, the formation of p-n heterojunction also plays a crucial role in improving the sensing performance towards HCHO. In this regard, Mott Schottky provides us evidence that the p-type PdO ( Majhi et al, 2019 ) and n-type of ZnO ( Xia et al, 2019 ) lead to the formation of p-n heterojunction at the interface, which is possibly responsible for the enhancement of the gas sensing ( Rakibuddin and Ananthakrishnan, 2015 ; Zhang et al, 2015 ; Park et al, 2016 ). When ZnO and PdO are brought in contact to form hetero-structure, electron transfer from ZnO to PdO to align the Fermi level (EF), leading to the formation of p-n heterojunction and charged free region (depletion layer) at the composite interface (electronic depletion on the side of ZnO and depletion of the hole on the side of PdO) as shown in Figure 7A .…”