Electrodeposition of MoS₂for Charge Storage in Electrochemical Supercapacitors

Abstract

Mo sulfide thin films were cathodically electrodeposited onto glassy carbon electrodes (GCE) from aqueous electrolytes containing 10 mM (NH 4) 2 MoS 4 and 0.2 M KCl. Film adhesion was adequate only for electrodes pretreated by potential cycling in 1.0 M HNO 3 and 0.1 M NaF to enhance the surface roughness and partially oxidize the GCE. Previous studies report direct cathodic electrodeposition of MoS 2 , but energy dispersive x-ray spectroscopy and x-ray diffraction suggest that the as-deposited film is closer in stoichiometry to MoS 3 , which can be converted to MoS 2 by annealing in Ar at 600°C for one hour. The charge storage capability of electrodeposited Mo sulfide films is studied here for the first time in 1.0 M Na 2 SO 4 over the thickness range 50 nm to 5 µm, and before and after high temperature annealing. The highest

Impedance Biosensing atop MoS2 Thin Films with Mo−S Bond Formation to Antibody Fragments Created by Disulphide Bond Reduction

“…After annealing, the EIS spectra for MoS 2 and Cu−MoS 2 thin films exhibit capacitive Nyqyuist plots that approach a vertical line, which is characteristic of electrochemical supercapacitors . However, after BSA adsorption, both annealed MoS 2 and Cu−MoS 2 thin films exhibit semicircular RC loops that are characteristic of the Randles equivalent circuit, as will be discussed below.…”

“…The Nyquist plots in Figures – exhibit different shapes that reflect the varying nature of these electrochemical interfaces. As previously reported, the annealed MoS 2 and Cu−MoS 2 thin films exhibit the capacitive behavior expected for electrochemical supercapacitors . This explains the nearly vertical lines that are observed in Figures and for MoS 2 and Cu−MoS 2 after annealing at 500 °C in Ar for 3 h. However, the impedance magnitude is small (0–200 Ω‐cm 2 ), so these nearly vertical lines can only be observed in the insets to Figures and .…”

“…During HDS, TMD‐containing catalysts with coordinatively unsaturated Mo sites exhibit a high affinity towards sulphur, allowing TMDs to bind and extract sulphur in various forms from hydrocarbon mixtures, and then catalyse subsequent C‐S bond clevage. The authors observe similar high affinity towards sulphur during electrodeposition of MoS 2 , Cu−MoS 2 and WS 2 from tetrathiometallate precursors . The as‐deposited films contain significant excess sulphur, as shown in Table , indicating that these materials desulphurize the electrolytes from which they are deposited.…”

“…All electrochemistry experiments were performed on MoS 2 and Cu-doped MoS 2 thin films~1.0 mm thick that were electrodeposited onto glassy carbon electrodes (GCE), as reported previously [32,33]. The GCE was inserted and used as the working electrode (A % 0.4596 cm 2 ) in a virgin Teflon three-electrode electrochemical cell with a Pt counter electrode and an Ag/AgCl reference electrode.…”

Single-chamber microbial electrochemical cell for CH4production from CO2utilizing a microbial consortium

“…23,24 The graphite anodes were then rinsed with ultrapure water and autoclaved at 121°C for 1 hour. For some experiments, this was followed by electrochemical activation with 300 potential cycles at 50 mV/s between +1.5 V and −0.4 V (vs Ag/AgCl) in an electrolyte containing 1.0 M HNO 3 and 0.10 M NaF.…”