Synthesis and characterization of bi2o3 nanostructures gas Sensing and energy storage application

Abstract

Bi2O3 nanostructures have attracted considerable attention due to their newlineexcellent properties such as abundant polymorphism ( , , and ), wide band gap newlinerange (2.0-3.96 eV), high refractive index, good electrochemical response, and high newlineoxygen-ion conductivity, resulting in many potential applications in photovoltaic cell, newlinegas sensors, photocatalysis, supercapacitor and so on. In the present work, Bi2O3 newlinenanostructures were synthesized by the electrochemical anodization of Bismuth (Bi) newlinefilms in three different electrolytes such as sodium hydroxide, citric acid and oxalic newlineacid. The effects of various electrolytes in the formation of three nanostructures were newlinestudied, and analyzed its structural, morphological, optical and electrochemical newlineproperties. Formation of phase pure , and phases of Bi2O3 was confirmed from newlineXRD and FT-Raman. By annealing, phase transformation from and newlinewere achieved. HR-SEM images showed the formation of faceted particle structure, newlinenanoporous and seaweed like nanostructures in sodium hydroxide, citric acid and newlineoxalic acid electrolytes respectively. Optical band gap has been determined from newlineDRS while the lattice defects such as oxygen vacancies and Bi interstitials were newlineidentified from PL. Different phases of Bi2O3 having various charge transfer newlineresistance were analyzed from EIS. CO2 gas sensing property was analyzed for Bi2O3 newlinehaving three different nanostructures. Among these, seaweed like nanostructure newlineexhibited highest response magnitude of ~101 % at 100 ppm of CO2 concentration. newlineElectrochemical characterization for supercapacitor application was analyzed in detail newlinefor these nanostructures by cyclic voltammetry, electrochemical impedance newlinespectroscopy and Mott-Schottky plot. Maximum capacitance of 557 F g -1 was newlineobserved for faceted particle nanostructure of Bi2O3 prepared from sodium hydroxide newlineelectrolyte. newline