Electrosynthesis of Cobalt Telluride Thin Films by Voltammetry Combined with Electrochemical Quartz Crystal Microgravimetry

Abstract

Cobalt telluride (CoTe) thin films were electrodeposited for the first time using alkaline solutions containing nitrilotriacetic acid (NTA), CoCl 2 , and K 2 TeO 3 . NTA was employed in order to shift the reduction potential of cobalt in the negative direction and to stabilize Co 2+ ions in alkaline electrolytes via the formation of Co-NTA complexes. The electrodeposition mechanism was investigated by linear sweep voltammetry (LSV) combined with electrochemical quartz crystal microgravimetry (EQCM). The formation of CoTe is proposed to occur through the reaction of Co 2+ with HTe − , which is generated by the reduction of TeO 3 2− via a 6-electron reduction pathway. A concurrent pathway consists of the stepwise reduction of TeO 3 2− to Te by a 4-electron process, followed by the 2-electron process reduction of Te to HTe − . The electrodeposited CoTe films were characterized by a variety of physical methods including scanning electron microscopy, energy dispersive X-ray, X-ray diffraction, and X-ray photoelectron spectroscopy. An optical energy bandgap of ∼1.86 eV was obtained by diffuse reflectance spectroscopy.

Electrosynthesis of CdS/MoS2 Using Electrodeposited MoSx: A Combined Voltammetry–Electrochemical Quartz Crystal Nanogravimetry Study

“…As in our companion studies, − the combination of linear sweep or cyclic voltammetry (LSV or CV) and electrochemical quartz crystal nanogravimetry (EQCN) offered insights into the film conversion process. Product confirmation was furnished by a variety of ex situ chemical characterization tools in concert.…”

“…The pH of each solution was adjusted with 1 M H 2 SO 4 or 1 M NaOH, as needed. Details of the electrochemical instrumentation including the potentiostat, electrodes, and EQCN are given elsewhere. − Briefly, all electrochemical experiments were performed at room temperature in a conventional three-electrode cell using an AT-cut, Au-coated quartz crystal (geometric area, 0.2 cm 2 ) working electrode, a Pt counter electrode, and a Ag/AgCl/3 M NaCl reference electrode. All potentials mentioned above are quoted with respect to this reference electrode.…”

Electrochemical Deposition of a Metal–Organic Framework and Subsequent Conversion to Cobalt Selenide

“…Further evidence for the surface composition of the CoSe films was obtained from XPS, as shown in Figure S8. For the Co 2p spectrum (Figure S8A), the binding energies at 780.8 and 796.8 eV can be assigned to Co 2p 3/2 and Co 2p 1/2 , respectively, revealing the Co 2+ oxidation state. , The Se 3d spectrum in Figure S8B showed two peaks centered at 54.5 and 59.6 eV, which are assigned to Se 3d 5/2 and Se 3d 3/2 , respectively …”

Effect of pH on the Synthesis of Cobalt Selenide Films by SILAR Method

“…The obtained nanostructured films could be used in the different fields such as solar cells, optical switching devices, energy storage devices, environmental applications, laser devices, photo catalysts, optical sensors and telecommunications devices. Abundant literature is available on the preparation of cobalt sulphide [33][34][35][36][37][38] , cobalt telluride [39][40][41][42] and cobalt selenide [43][44][45][46][47][48] thin films via various deposition techniques. In this work, SILAR method was selected to produce cobalt selenide films due this deposition technique has many advantages if compared to other deposition techniques.…”