The development of efficient and durable electrocatalysts for the methanol oxidation reaction (MOR) is crucial for advancing alkaline direct methanol fuel cells. Herein, a Pd/MnO2/exfoliated boron (Pd/MnO₂/eB) ternary composite was synthesized via solvent-assisted boron exfoliation, hydrothermal growth of MnO₂, and ultrasonic integration of Pd nanoparticles. Structural characterization indicates the successful formation of crystalline MnO2 decorated with Pd nanoparticles on eB sheet. The ternary composite exhibited higher electrocatalytic activity toward MOR in 2 M NaOH containing 2 M methanol, achieving a maximum forward oxidation current density of 4.5 mA mg− 1 Pd as compared to Pd/C (2.75 mA mg− 1 Pd). The temperature-dependent studies of Pd/MnO2/eB revealed that increasing temperature enhanced methanol oxidation by promoting reactant diffusion, hydroxide-ion transport, and electron-transfer kinetics, with optimum performance achieved at 323 K. Arrhenius analysis yielded an apparent activation energy of 47.9 kJ mol− 1, while Eyring analysis gave an activation enthalpy of 45.5 kJ mol− 1, an activation entropy of -113 J mol− 1 K− 1, and activation Gibbs free energies of 79.8–83.2 kJ mol− 1, indicating that methanol oxidation proceeds through the formation of a ordered activated complex with a moderate energy barrier. A plausible mechanism is proposed in which Pd catalyses methanol adsorption and dehydrogenation, MnO2 supplies reactive hydroxyl species for oxidative removal of poisoning intermediates, and exfoliated boron enhances electron transport.
The increasing human impact on aquatic ecosystems due to the widespread use of pharmaceuticals such as diclofenac calls for the development of innovative and affordable techniques for detecting and quantifying these contaminants in water. Herein, a technique for detecting diclofenac in phosphate buffer and lake water was developed from palladium-doped graphitic carbon nitride (Pd/GCN) deposited on a glassy carbon electrode. The composite material was synthesized by doping palladium into graphitic carbon nitride. The FTIR and XPS results confirmed the doping of palladium onto the graphitic carbon nitride. The specific surface area of modified Pd/GCN is 73.399 m²/g, which is twice as higher than the pristine GCN. SEM results revealed the morphology of pristine GCN displaying flake like structure while the modified graphitic carbon nitride showed the tiny palladium particles attached on the observed on the surface. The cyclic voltammetry analysis indicated an irreversible peak around at an anodic potential of 0.65 V for the oxidation of diclofenac. The reaction mechanism on Pd/GCN was controlled by the mixture of diffusion and adsorption process. The synthesized Pd/GCN exhibited high catalytic activity in the detection of diclofenac in water with a limit of detection of 0.065 µM, in the linear range of 0.1 to 80 µM. The developed sensor has shown great potential for detecting diclofenac in environmental water sources.
Electrochemical nitrate reduction enables direct NH3 production from wastewater. Herein, a boron − nitrogen co-doped carbon (BNC) catalyst was synthesized from substituted terpyridine, and the effects of various electrolytes were systematically studied. In 0.1 M HNO3, NH3 Faradaic efficiency (FE) reached 50
In this study, the modification of palm kernel shell-based Agro-Waste into an electrocatalytic material has been successfully carried out. The green hydrothermal method through temperature and time variations was chosen in the process of modifying PKS carbon into nanoporous carbon (NC-PKS). SEM-EDX, XRD, and FTIR characterization data show the success of this process, which is marked by fundamental changes in morphology, elemental composition, diffractogram peaks, and IR absorption of functional groups that make up carbon. The morphology of NC-PKS is characterized by honeycomb-shaped hexagonal pores with constituent elements including 85.111
In this work, the electrochemical efficiency of copper based layered double hydroxides (Cu-LDH) towards CO2 electroreduction (CO2ER) was investigated. Cu2Al-CO3 LDH was synthesized by coprecipitation and characterized using powder X-ray diffraction (PXRD), atomic pair distribution functions (PDFs) and electron microscopies (SEM-TEM). The CO2ER performance of Cu2Al-CO3 LDH was evaluated in a three-electrode cell under potentiostatic conditions. The influence of key electrolysis parameters, including electrolyte composition, concentration, pH and applied potential, was systematically examined. Cyclic voltammetry was used to characterize the Cu-LDH modified electrode and revealed an electrochemical activation of the copper atoms occurred in the presence of CO2 at Eapp ≤ -1.3 V vs. SCE. Optimal conditions were identified in 0.5 M KCl at Eapp = -1.4 V vs. SCE with a final pHf in the range 5.5-6.0 leading to formation of formate. The evolution of the structure and the composition of the Cu-based LDH particles after electrolysis was investigated by XRD, PDF and XPS to provide insight into the active phases formed under CO2ER conditions.
