Tailoring synthesis strategies for polyaniline-prussian blue composite in view of energy storage and H2O2 sensing application

The synergetic effect of integrating two different electroactive materials like polyaniline (PANI) and Prussian blue (PB) to design a hybrid electrode could afford enhanced electrochemical properties. PANI-PB composites are versatile material and have been extensively utilized over last few decades in electrochemical sensors and supercapacitors. However, it is necessary to optimize and finetune the process of synthesis of PANI-PB composite so that its efficacy can be maximized for potential device application. From this point of view, five different strategies were adopted to synthesize PANI-PB composite by ex-situ/in-situ deposition of PB on PANI and vice-versa. The composites were characterized using XRD, X-ray fluorescence spectroscopy and FESEM to explore its nature. The performance of these composites was compared by carrying out electrochemical studies (like cyclic voltammetric, galvanostatic charge discharge, electrochemical impedance spectroscopy and amperometry) to evaluate its potential for energy storage and H2O2 sensing application. It was found that the hybrid prepared by ex-situ deposition of PANI on PB particles afforded specific capacitance of 774 F g−1 and energy density 69.2 W h kg−1 which is suitable for energy storage application. The composite prepared using in-situ co-synthesis of PB on PANI afforded high sensitivity value 485 μM mM−1cm−2 with linear range 10–500 μM for detection of H2O2. Furthermore, the sensor electrode displayed very high specificity to H2O2 with no interference from ascorbic acid, urea and glucose. Mechanism behind the energy storage and H2O2 sensing property of composite which afforded excellent performance was elucidated. The amount of PB in the composite and its proper spatial distribution in conducting matrix of PANI were found to be key factors for efficiently tapping its full potential. The present studies emphasize importance of tailoring strategies for synthesis of PANI-PB composites to attain optimized PB content, particle size and relative spatial distribution of PB and PANI to suit desired applications.