Synthesis of hierarchical Mn3O4 nanowires on reduced graphene oxide nanoarchitecture as effective pseudocapacitive electrodes for capacitive desalination application

We present a hierarchical network architecture fabrication of pseudocapacitive Mn3O4 nanowires immobilized on reduced graphene oxide (Mn3O4/RGO) hybrids for effective capacitive deionization (CDI). A hydrothermal synthesis process was employed for constructing Mn3O4/RGO nanoarchitecture with hierarchical pores to ease the interaction with salt ions. Physico-chemical analysis verified the Mn3O4 nanowires with few microns sized length and diameter of 20-30 nm were evenly immobilized on the surfaces of the RGO. With this tailored nanoarchitecture, the Mn3O4/RGO based electrode shows ideal pseudocapacitive behavior with a higher capacitance of (Cs) of 437 F g(-1), the energy density of 41.12 Wh kg(-1) and power density of 400 W kg(-1) at 1 A g(-1) in 1 M NaCl solution. Benefiting from the fascinating electrochemical features, the Mn3O4/RGO nanoarchitecture constructed CDI electrode exhibited high electrosorption capacity (SAC) of 34.5 mg g(-1) at 1.2 V with a high salt adsorption rate (ASAR) of 1.15 mg g(-1) min(-1) in 1000 mg L-1 NaCl solution. The much improved SAC, ASAR, and recyclability could be attributed to the distinctive pseudocapacitive nanoarchitecture, which improves the sodiation/desodiation. The present investigation indicates that the Mn3O4/RGO nanoarchitecture is a capable CDI electrode material for desalination application. (C) 2020 Elsevier Ltd. All rights reserved.