Transition metal (Ni, Cu and Fe) doped MnS nanostructures: Effect of doping on supercapacitance and water splitting

Increasing demand for sustainable energy has boosted the exploration of inexpensive and efficient catalysts. Transition metal sulfides have been proven as efficient electrocatalysts for energy storage or energy generation applications. Herein, cubic phase alpha-MnS and transition metal (Cu2+, Fe3+, and Ni2+) doped MnS nanoparticles were synthesized via the hot injection method from their piperazinyl dithiocarbamate complexes, respectively. The morphology of pristine and TM-doped MnS nanoparticles was studied using transmission electron micro-scopy (TEM) and scanning electron microscopy (SEM) analysis, while optical and structural properties were studied using UV-visible spectroscopy and powder X-ray diffraction (p-XRD), respectively. p-XRD analysis confirmed the successful incorporation of dopants into MnS lattice structure and suitability of heterocyclic dithiocarbamate complexes for phase/composition controlled synthesis of nanomaterials. The effect of doping on electrocatalytic properties was also investigated. The MnS-based electrodes doped with Ni and Fe presented satisfactory specific capacitances of 840 and 900 F/g at 2 mV/s scan rate. In addition, the testing for electro-catalysis for the water-splitting process demonstrated that Ni-MnS had a superior performance for HER with a eta of 132 mV at 10 mA/cm2 and Tafel slope of 44 mV/dec. On the other hand, Fe-MnS showed better performance towards OER with a eta of 280 mV at 10 mA/cm2 and a Tafel slope of 60 mV/dec.

Automated summary

The demand for sustainable energy has led researchers to explore inexpensive and efficient catalysts. Transition metal sulfides, such as MnS doped with Cu2+, Fe3+, and Ni2+, have shown promise as effective electrocatalysts for energy storage and generation. This study synthesized cubic phase alpha-MnS and doped MnS nanoparticles and analyzed their morphology, optical and structural properties. The doping of Ni and Fe into MnS electrodes resulted in satisfactory specific capacitances and superior performance for water-splitting processes.