Ethylenediamine-assisted growth of multi-dimensional ZnS nanostructures and study of its charge transfer mechanism on supercapacitor electrode and photocatalytic performance

Abstract

In recent years, much interest has been raised by materials with multi-purpose characteristics as the performance of electrochemical energy devices such as supercapacitors and photocatalytic activities depend strongly on the properties of materials. This study delineates various parameters like morphology, energy band gap, charge transfer resistance, different defect states, diffusion coefficient and functional groups adsorbed on the surface of material to assess the performance of supercapacitor electrodes and photocatalytic degradation efficiency of synthesised multi-dimensional ZnS nanostructures. Ethylenediamine (EN)-mediated multi-dimensional ZnS nanostructures were grown by the solvothermal route. One-dimensional (1D), 2D and 3D morphologies were obtained by varying the ratio of de-ionised water and EN, taken as 1:3, 1:2 and 1:1, respectively. The EN molecules effectively capped most of the surfaces of the ZnS nanoparticles formed, preventing agglomeration of nanoparticles due to the decrement in surface energy. The oriented attachment of these clusters resulted in the formation of 1D, 2D and 3D morphologies. The plausible chemistry in the formation of 1D, 2D and 3D nanostructures has been elaborated. Charge transfer properties of prepared electrodes have been examined using the electrochemical impedance spectroscopy (EIS) technique because better charge transfer causes diminishing electron/hole recombination and hence better photodegradation efficiency. Among the synthesised materials, the 2D nanostructure degraded the eosin Y dye to maximum 90.71% efficiency with rate constant 34 × 10−3 min−1. 2D nanostructures possess better charge transfer and hence better photodegradation efficiency. Various studies using methods of UV-vis, Fourier-transform infrared, Brunauer–Emmett–Teller, x-ray photoelectron spectroscopy and photoluminescence spectra are in good agreement with the obtained photodegradation results. After analysing cyclic voltammetry curves and EIS, a higher diffusion coefficient is obtained for 1D nanostructure material, hence a higher specific capacitance and higher energy density of 159.12 F g−1 and 22.75 KWh kg−1 are found in this case. Only 9% loss of specific capacitance is found after 1000 cycles, showing a relatively high cycling stability in 3D nanostructures. The excellent supercapacitive property can be attributed to the porous structure and high specific surface area. Thus, the synthesised multi-dimensional ZnS nanostructures are proved to be a potential candidate for both photocatalytic and supercapacitor electrode performance.

Synergetic and anomalous effect of CNTs in the sulphide‐based binary composite for an extraordinary and asymmetric supercapacitor device

“…[16][17][18] Out of various metal phosphates and sulphides, zinc sulphide (ZnS) and silver sulphide (Ag 2 S) have been proven to be plausible as electrode materials in ESDs because of their better capacitance and good electrochemical stability. [14,19,20] For instance, Bhushan et al have grown multi-dimensional nanostructures of ZnS by a solvothermal approach and documented the specific capacitance to be 159.12 F g À1 at 20 mV s À1 with an E d of 22.75 Wh kg À1 . [19] The capacitance retention for a ZnS based electrode was found to be 72.27% after 1000 cycles.…”

Coelectrodeposition of NiSe/ZnSe Hybrid Nanostructures as a Battery-Type Electrode for an Asymmetric Supercapacitor

“…A pair of redox peaks can be clearly seen in all CV curves from the anodic and cathodic sweeps of each electrode, indicating that NZSe composites exhibited a faradaic charge storage mechanism belonging to battery-type materials. The NZSe hybrid electrodes exhibit similar CV curves to the Ni/Zn-based compounds including their oxides, sulfides, and hydroxides. − The two pairs of redox peaks at ∼0.50 and 0.28 V and 0.58 and 0.22 V are attributed to the redox reactions of Ni 2+ /Ni 3+ and Zn 2+ /Zn 3+ /Zn 4+ , as described by the following equations …”

A General Polymer‐Oriented Acid‐Mediated Self‐Assembly Approach toward Crystalline Mesoporous Metal Sulfides

“…For ZnS-1.0, the characteristic peaks at 1616 and 3468 cm −1 are associated with the stretching and banding vibrations of O−H bonds of physisorbed water, and the peak around 613 cm −1 should be assigned to ZnS stretching (Figure S10a, Supporting Information). [37,38] Two peaks at 1123 and 1047 cm −1 can be corresponded to the stretching vibration of CN bond for the residual PEI. [36,38,39] The C 1s high-resolution XPS spectrum of ZnS-1.0 displays two bonding configurations, namely, CN (285.8 eV) and CC (284.8 eV), respectively (Figure S10b, Supporting Information).…”