Layer‐by‐Layer Motif Heteroarchitecturing of N,S‐Codoped Reduced Graphene Oxide‐Wrapped Ni/NiS Nanoparticles for the Electrochemical Oxidation of Water

• Published in: ChemSusChem 2020-06, Vol.13 (12), p.3269-3276
• Main Authors: Zakaria, Mohamed Barakat, Guo, Yanna, Na, Jongbeom, Tahawy, Rafat, Chikyow, Toyohiro, El‐Said, Waleed A., El‐Hady, Deia A., Alshitari, Wael, Yamauchi, Yusuke, Lin, Jianjian
• Format: Article
• Language: English
• Subjects: Annealing; Coordination polymers; electrocatalysis; Electrochemical oxidation; Face centered cubic lattice; Flakes; Graphene; heterostructures; metal carbides; metal sulfides; Morphology; Nanocomposites; nanohybrids; Nanoparticles; Nickel sulfide; Nitrogen; Oxygen evolution reactions; Phase transitions; Synergistic effect
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202000159

A new heterostructured material is synthesized with lamellar arrangements in nanoscale precision through an innovative synthetic approach. The self‐assembled Ni‐based cyano‐bridged coordination polymer flakes (Ni‐CP) and graphene oxide (GO) nanosheets with a layered morphology (Ni‐CP/GO) are used as precursors for the synthesis of multicomponent hybrid materials. Annealing of Ni‐CP/GO in nitrogen at 450 °C allows the formation of Ni3C/rGO nanocomposites. Grinding Ni‐CP/GO and thiourea and annealing under the same conditions produces N,S‐codoped reduced GO‐wrapped NiS2 flakes (NiS2/NS‐rGO). Interestingly, further heating up to 550 °C allows the phase transformation of NiS2 into NiS accompanied by the formation of a face‐centered cubic (FCC‐Ni) metal phase between NS‐rGO layers (FCC‐Ni‐NiS/NS‐rGO). Among all the materials, the resulting FCC‐Ni‐NiS/NS‐rGO exhibits good electrocatalytic activity and stability toward the oxygen evolution reaction (OER) owing to the synergistic effect of multiphases, the well‐designed alternating layered structures on the nanoscale with abundant active sites. That's a wrap: Self‐assembled Ni‐based cyano‐bridged coordination polymer flakes (Ni‐CP) and graphene oxide (GO) nanosheets are used to synthesize three functional heterostructured electrodes, Ni3C/rGO, NiS2/NS‐rGO, and FCC‐Ni‐NiS/NS‐rGO, through thermal treatment of layered Ni‐CP/GO hybrids in nitrogen. Among all the materials, the resulting FCC‐Ni/NiS/NS‐rGO exhibits good electrocatalytic activity and stability toward the oxygen evolution reaction owing to synergistic effects of the multiphases.