Siderophore mediated in vitro synthesis of electrocatalytic nanocrystallite struvite variants for highly efficient and durable hydrogen evolution reaction

Abstract

We report in vitro nanocrystallite variants of Ni and Co struvite formed by bacterial siderophore using the green synthesis method. Assembling of siderophore mediated nanocrystallite struvite variants in the presence of Mg2+, Ni2+ and/or Co2+ and PO43− ions (pH- 9.0) has been investigated. The nanocrystallite struvite was characterized by field emission scanning electron microscopy with energy dispersive X-ray spectroscopy. Fourier transform infrared spectroscopy, Raman spectroscopy for their structural, and X-ray powder diffraction for its crystal structure in conjunction with density functional theory. A strategy described here can be explored for rapid synthesis and a large-scale production of modified struvite nanocrystallite materials. Moreover, the potential implications of siderophore accompanying the struvite variant formation facilitated by sequestering electroactive metal ions are discussed. More importantly, the Ni struvite variant demonstrated high electrochemical hydrogen evolution reaction (HER) with overpotential of −59 mV at 10 mA/cm2 current density which is at par with the benchmark Pt electrocatalysts. The stability of Ni struvite during the HER at overpotential and at 100 mA/cm2 applied current density has been demonstrated.