NiO nanoparticle embedded polyaniline (NiO-PANI) for enhanced ammonia and water oxidation reactions Pratiksha D. Tanwade 1 , Bhaskar R. Sathe 1,2 1 Department of Chemistry, Dr Babasaheb Ambedkar Marathwada University, India, 2 Department of Nanotechnology, Dr Babasaheb Ambedkar Marathwada University, India Electrochemical ammonia and water oxidation are a practical substitute for hydrogen and oxygen in low- temperature fuel cell reactions. Herein this work describes highly dispersed nickel oxide nanoparticles (NiO-NPs) on polyaniline (NiO-PANI) which was synthesized by the chemical method. The as-synthesized electrocatalysts were characterized by X-ray diffraction (XRD) confirming the face-centered cubic (FCC) structure, and morphological features were analyzed by using transmission electron microscopy (TEM) showed that crumpled nanosheets of PANI decorated by NiO-NPs (~14.97 nm). The X-ray photoelectron spectroscopy (XPS) showed variable oxidation states of Ni 2+ /Ni 3+ in NiO-PANI. Raman spectra demonstrate efficient support of C-framework and more defect formation in NiO-PANI compared to PANI. The cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectral studies of NiO-PANI demonstrate higher electrochemical activity and feasible electron transfer corresponding to ammonia oxidation reaction (AOR) and oxygen evolution reaction (OER). An excellent activity for AOR on NiO-PANI at 10 mA/cm 2 is shown at an ultralow potential of E = 1.25 V vs RHE, and a dominant OER is present at an anodic peak potential of E = 1.53 V vs RHE. Chronoamperometric (i-t) measurement shows NiO-PANI having stability at 1.35 V (peak potential) and long term i.e.,(15 hr) current performance towards AOR. An excellent result for electrocatalytic AOR and OER was from the availability of additional anchoring sites, cooperative interactions of both NiO with PANI, and, increased overall conductivity of nanocomposite material. This work offers a synthetic method for the fabrication of noble metal-free electrocatalytic systems for remarkable outcomes like hydrogen production. oxidation ammonia and other hydrogen-rich species and for direct fuel cells-based energy production.
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