Papers by Keyword: Electrosynthesis

Abstract: The electrocatalytic ammonia synthesis using water (along with nitrogen) as a hydrogen source is proposed as an alternative green and clean technology to the energy-intensive and CO₂-emitting process (Haber-Bosch) for ammonia production. Besides, a selective electrocatalyst for ammonia synthesis versus the competing hydrogen evolution remains elusive. This study aims to investigate the electrocatalytic activity of non-noble metal Co and Fe-free perovskite oxide-based composite cathode (La_0.75Sr_0.25Cr_0.5Mn_0.5O_3-δ-Ce_0.8Gd_0.18Ca_0.02O_2-δ) towards ammonia synthesis from H₂O and N₂. The electrocatalyst was synthesized via a sol-gel process and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was successfully with a maximum formation rate of 2.5 × 10^-10 mol s^-1 cm^-2 and Faradaic efficiency of 0.52% at 400 oC and applied voltage of 1.4 V. The results demonstrated that the proposed non-noble metal-based electrocatalyst is a promising material for the carbon-free ammonia synthesis process.

Abstract: In the present work, oxalic acid doped molecularly imprinted conducting polyaniline film for melamine detection was prepared by in-situ-electrochemical polymerization on the glassy carbon electrode (GCE) using melamine as template. The optimal monomer/template molar ratio was attained to be 0.2:0.1:0.01 (aniline: oxalic acid: melamine) and molecular recognition properties towards melamine were evaluated by differential pulse voltammetry. Under optimal conditions the imprinted polymer film was used to detect different concentrations of melamine in standard solutions and real milk samples. Compared with the nonimprinted polymer (NIP), the molecularly imprinted polymer (MIP) film showed higher affinity and sensitivity towards melamine with a linear range, quantification limit and detection limit of 0.5-200 nM, 1.375 nM and 0.413 nM respectively. Furthermore, the polymer blend film showed good selectivity toward melamine, stability, reproducibility and practical applications for the determination of melamine in infant formula milk with the recovery of 92.32-102.49%. The doping of the polymer with oxalic acid enhanced the conductivity and sensitivity of the sensor.

Abstract: Nanostructured manganese dioxide films were obtained by electrosynthesis using 0.02-0.15 M KMnO4 solutions. The diffusion-controlled deposition mechanism is based on the reduction of anionic MnO4- at the cathode surface. The method allowed the fabrication of porous films for application in electrochemical supercapacitors (ES). It was shown that film porosity is beneficial for the charge transfer during deposition, crack prevention in thick films and electrolyte diffusion in fabricated ES electrodes. Porous nanostructured films showed good capacitive behavior in the 0.1 M Na2SO4 electrolyte in a voltage window of 1V. The specific capacitance decreased with increasing scan rate due to the diffusion limitation in the porous manganese dioxide electrodes