Amideddin Nouralishahi

A mixed-metal ternary chalcogenide, cobalt molybdenum telluride (CMT), has been identified as an efficient tri-functional electrocatalyst for seawater splitting, leading to enhanced oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR). The CMT was synthesized by a single step hydrothermal technique. Detailed electrochemical studies of the CMT-modified electrodes showed that CMT has a promising performance for OER in the simulated seawater solutions, exhibiting a small overpotential of 385 mV at 20 mA cm⁻², and superior catalyst durability for prolonged period of continuous oxygen evolution. Interestingly, while gas chromatography analysis confirmed the evolution of oxygen in an anodic chamber, it showed that there was no chlorine evolution from these electrodes in alkaline seawater, highlighting the novelty of this catalyst. CMT also displayed remarkable ORR activity in simulated seawater as indicated by its four-electron reduction pathway forming water as the dominant product. One of the primary challenges of seawater splitting is chlorine evolution from the oxidation of dissolved chloride salts. The CMT catalyst successfully and significantly lowers the water oxidation potential, thereby separating the chloride and water oxidation potentials by a larger margin. These results suggest that CMT can function as a highly active tri-functional electrocatalyst with significant stability, making it suitable for clean energy generation and environmental applications using seawater.

This research studies the improving effects of graphene porous (GP) on the supercapacitive performance of a polyaniline/graphene porous (PANI/GP) nanocomposite. GP nanosheets were synthesized via chemical vapor deposition, and PANI/GP was electrochemically composited through successive cyclic voltammetry. The samples were characterized by fast Fourier transform infrared (FTIR), x‐ray diffraction (XRD), and scanning electron microscopy (SEM), and energy‐dispersive x‐ray spectrometry (EDS) techniques. Porous GP nanosheets were uniformly dispersed in the composite structure. Furthermore, the electrochemical performances of the synthesized samples were compared using galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Incorporating GP into the PANI significantly increased specific capacitance from 276 (in PANI) to 577 F/g (in PANI/GP). The electrochemical stability of electrodes was compared during 1000 successive charge/discharge cycles. After 1000 cycles, PANI/GP kept 90% of its initial capacitance, and only 25% of the charge storage capacitance of bare PANI remained.

In the present study, activated carbon prepared from cedar wood was synthesized, ‎via NaOH activation, and optimized to be used as the adsorbent for Pb2+ removal ‎from aqueous solutions in a batch process mode. The physicochemical properties ‎of the synthesized adsorbent were examined by SEM, FTIR and BET analysis. In ‎order to determine the optimum operational conditions, the effects of different ‎parameters including pH, adsorbent dosage, contact time, temperature, and initial ‎Pb2+concentration on the adsorptive performance of synthesized samples were also ‎investigated. According to the obtained results, the highest Pb2+ ion adsorption ‎capacity (971.9 mg/g) took place at the optimum operational condition of pH=4, ‎adsorbent dosage of 0.025 g/L, contact time of 60 minutes, 300 ppm of Pb2+ and ‎‎30 ℃. The results showed that among Langmuir, Freundlich, and Temkin ‎isotherms, the obtained data were fitted the best with the Freundlich model. ‎Additionally, the process of Pb2+ adsorption was consistent with the pseudo-‎second-order kinetics model, indicating that chemical adsorption was the dominant ‎mechanism of adsorption. Finally, according to the calculated thermodynamic ‎parameters, i.e., ∆H°, 〖∆S〗^° & 〖∆G〗^°, Pb2+ adsorption on activated cedar ‎wood can be considered as an exothermic and spontaneous process.‎