Superlative Photoelectrochemical Properties of 3D MgCr- LDH Nanoflowers influencing towards Photoinduced Water Splitting Reactions

Layered double hydroxides (LDHs) are competent photocatalysts for water splitting reactions, vital to produce solar fuels, but their restricted available reactive sites, slow mass and charge transfer, are yet remain a challenge. To surmount these lacunas, Nanoflowers-like three-dimensional (3D) open structure of MgCr-LDH have been designed in a substrate-free path by one-step formamide assisted hydrothermal treatment followed by visible light irradiation and utilized as efficient photocatalysts for the H2 and O2 production. The structural, morphological, optical and photoelectrochemical (PEC) properties of the MgCr-LDH nanoflowers were extensively examined, by various physico-chemical characterization techniques. Moreover, the well-designed 3D MgCr-LDH nanoflowers with open structure were formed by a stacking of numerous 2D nanosheets, which inherently triggered with magnificent PEC properties, including high current density of 6.9 mA/cm2, smallest arc of the Nyquist plot (59.1 Ω cm−2) with photostability of 6000 s thereby enhancing the photocatalytic water splitting activity along. Moreover such a perfectly self-stacked 2D nanosheet in 3D MgCr-LDH possess defect sites as enriched 50% oxygen vacancy resulting a good contact surface within the structure for effective light absorption and easy electron and hole separation, facilitates the adsorption of protons and intermediate of water oxidation. Further, the doped Cr3+ pull up electrons from water oxidation intermediates, thereby displaying superior photocatalytic H2 and O2 production activity of 1315 µmol/h and 579 µmol/h, respectively. Favorable oxygen vacancy type defect surface with Cr3+ dopant in MgCr-LDH triggers significant PEC properties, which influences the easy charge transfer and separation mechanism and robustly enhance the photocatalytic performance of the nanoflower.