Inorganic Tri-metallic LDHs And GO@Ni-MOF Composites As An Efficient Bifunctional Electrocatalyst For Overall Water Splitting

In present era,there is enormous need of the world to design versatile porous nano-materials with amended crystalline structure,improved surface morphology,pore sizes and surface area to fulfill ever increasing global energy consumption.Lot of efforts has been done for exploring and discovering the novel materials to achieve the desired objectives.In this regards diversities of layer double hydroxides(LDHs)and metal organic framework(MOFs)have taken considerable attention to fulfill the world requirements due to their surprising and interesting properties.Different techniques have been applied to investigate the crystalline and surface properties of the fabricated catalysts such as X-ray powder diffraction(PXRD),Scanning electron microscopy(SEM),high resolution transmission electron microscopy,Fourier transform infrared spectroscopy(FT-IR),X-rays photoelectron spectroscopic analysis and Thermo-gravimetric analysis(TGA).In this work ultrathin three fold NiCoV layered double hydroxides(LDHs)nanosheets deposited over nickel foam(NF)substrate via hydrothermal treatment and used as effective electrode concerning for overall splitting of water in is alkaline media.The lateral length of nanosheets is almost few hundreds of nanometers accompanying the width of?10 nm.The NiCoV-LDHs/NF(6:1:1)electrode exhibited the maximum catalytic efficiency.It depicts an optimized catalytic performance for OER current density of 20 mA cm 2 costing potential of 498 mV and HER current density of 80 mA cm-2 by costing potential of-1.1 V.Its extraordinary performance is additionally described in its short Tafel Slope showing 160 and 79.0 mV dec-1 for OER and HER respectively with high stability.Beside this NiCoV-LDHs/NF(6:1:1)has high overall water splitting capacity producing current 10 mA cm-2 by costing potential 1.55V.These extraordinary activities are basically ascribed to synergistic coupling of the threefold metal system with Ni-foam.Secondly,we prepared Ni-MOF by combining nickel nitrate hexahydrate with 1,3,5-tricarboxylic acid and nitrogen donor 4,4-bipyridine ligands also coupled with graphene oxide(GO)to prepare nickel-MOF and GO hybrid(Ni-MOFGO)as well as use different wt%of GO to grow onto NF for preparing Ni-MOFGO/NF hybrids.Aforementioned as prepared Ni-MOFGO/NF hybrids acts as a highly active,efficient,robust,bifunctional catalysts with superior selectivity for OER as well as HER water splitting.The enhanced electrocatalytic properties and high stability of Ni-MOFGO/NF hybrids alkaline media is because of great porous scaffold framework,which is more effective for the transportation of charge carriers.The Ni-MOFG06%/NF illustrates an optimized catalytic performance with OER current density of 0.25 mAcm-2 costing potential of 581 mV while HER current density of 50 mAcm-2 costing-1.26 V with Tafel slopes 51 mV dec-1 and 72.0 mV dec-1 for OER and HER respectively.The present investigation is an encouragement and a gate way to build the economical and robust electrocatalysts based on earth abundant materials for overall water splitting.