Research on compositional and structural engineering of nanostructured electrodes for high functionality has been a pivotal aspect in the development of energy harvesting and storage technology. Here in this work, we aim to report a detailed analysis of a much less investigated binary metal chalcogenide MnMoS4 for photoelectrochemical (PEC) water splitting and supercapacitor applications. While spontaneous responsiveness to redox reactions is very crucial for the choice of the electrode material in supercapacitors, a good photo-response and charge transportability are the desired parameters in PEC applications. MnMoS4 nanosheets were grown by a direct, one-step, low-temperature surfactant-assisted solvothermal method on FTO, which was used as the photoanode for O2 evolution in water splitting while a similar growth method was carried out on carbon cloth for fabrication of an asymmetric supercapcitor. Photoelectrochemical analysis was performed with a linear potential sweep under simulated solar irradiation (AM 1.5 G, 100 mW/cm2) with 0.5M Na2S and 0.5M Na2SO3 electrolyte and Pt counter electrode where an ABPE of 0.92% at 0.59V was obtained. The MnMoS4 carbon cloth-based fabricated electrode shows a high capacitance of 465.4F g-1 at a current density of 1A g-1 with retention of 93.4% electrochemical activity after 3000 cycles. Structural and morphological analysis was carried out with the help of FESEM, XRD, and EDAX while Raman spectroscopy was done for compositional analysis. Further, we have attempted to induce porosity in the nanosheets with a help of a two-step solvothermal approach where MoS2 nanosheets were synthesized in the first step, followed by solvothermal diffusion of Mn2+ ions in the unannealed MoS2. This was observed to generate an interesting morphology with enhanced porosity leading to better electrochemical performance. Through this work, we aim to inspire further research on the synthesis and properties of binary metal chalcogenides for sustainable energy applications and explore their multi-functionality.

A combined photoelectrochemical and electrochemical analysis of MnMoS4 nanostructured electrodes for multifunctional applications

ACS Spring Meeting 2021

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