Ethanol changes the Pd selectivity towards the different pathways of formic acid oxidation by eliminating the indirect pathway and slowly decreasing the direct pathway activity, owing to ethanol potential depdant adsorption orientations.

The relatively high cost of all-vanadium redox flow batteries (VRFBs) limits their widespread deployment. Enhancing the kinetics of the electrochemical reactions is needed to increase the power density and energy efficiency of the VRFB, and hence decrease the kWh cost of VRFBs. In this work, hydrothermally synthesized hydrated tungsten oxide (HWO) nanoparticles, C76, and C76/HWO were deposited on carbon cloth electrodes and tested as electrocatalysts for the VO2+/VO2+ redox reactions. Field Emission Scanning Electron Microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscope (HR-TEM,), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and contact angle measurements were used to characterize the electrodes’ material. The addition of the C76 fullerene to HWO was found to boost the electrode kinetics towards the VO2+/VO2+ redox reaction, by enhancing the conductivity and providing oxygenated functional groups at its surface. A composite of HWO/C76 (50 wt% C76) was found to be the optimum for the VO2+/VO2+ reaction, showing a ΔEp of 176 mV, compared to 365 mV in the case of untreated carbon cloth (UCC). Besides, HWO/C76 composites showed a significant inhibition effect for the parasitic chlorine evolution reaction due to the W-OH functional groups.

Polystyrene nanospheres are of great importance in 3D hard templating along with many other fields like pharmaceuticals and coatings. Therefore, it is important to be able to prepare polystyrene beads...

Renewable energy sources require high-efficiency storage systems to allow for its integration within the electrical grid and to supply that energy when needed. All-vanadium redox flow batteries (VRFBs) are very promising for this application because they can store high amounts of energy, are designed to work for long periods, and their solutions can be used indefinitely.1 VRFBs have various advantages when combined with renewable energy sources. The relatively high cost of VRFBs limits their widespread deployment. Enhancing the kinetics of the electrochemical reactions is needed to increase the power density and energy efficiency of the VRFB, and hence decrease the kWh cost of VRFBs. Different carbon materials are used as electrodes in VRFBs (carbon felt, paper and cloth), and each of these materials affects the performance of the battery differently either through sluggish kinetics or a high chance for parasitic reactions catalyzation.2 Modification of these electrodes by carbon-based3 or metal oxides2 nanomaterials can increase the power density of the battery and suppress the parasitic reactions. Some metal oxides like tungsten oxide4 can enhance vanadium reactions alone or when used as composites with nanocarbon materials. This work aims at enhancing the VRFBs negative half-cell reaction (V2+/V3+) kinetics and inhibiting the hydrogen evolution parasitic reaction. Carbon cloth electrodes were modified, using different tungsten oxide nanostructures such as nanowires, nanoflakes, and nanospheres, and tested at different loadings. The results suggest that the change in tungsten oxide structure would lead to a change in the electrode overall performance as a result of changing the electrical conductivity, the wettability of the electrodes, the coverage of the carbon cloth, and the number and nature of the active sites available to catalyze the V2+/V3+ reaction, with the tungsten oxide nanowires showing to be the best electrode modifier. References: R. K. Sankaralingam, S. Seshadri, J. Sunarso, A. I. Bhatt, and A. Kapoor, Journal of Energy Storage, 41, 102857 (2021). A. Wodaje Bayeh et al., Sustainable Energy & Fuels, 5, 1668–1707 (2021). F. A. E. Diwany, B. A. Ali, E. N. E. Sawy, and N. K. Allam, Chem. Commun., 56, 7569–7572 (2020). M. Faraji, R. Khalilzadeh Soltanahmadi, S. Seyfi, B. Mostafavi Bavani, and H. Mohammadzadeh Aydisheh, J Solid State Electrochem, 24, 2315–2324 (2020).

The dependence on fossil fuels to meet the world energy demand caused several social, economical, and environmental problems. An immediate switch to sustainable, clean, and renewable sources of energy is a necessity. To achieve this switch, developing efficient technologies to convert renewable energy sources into electricity is a necessity but not enough due to the intermittent behavior of renewable sources. The incorporation of energy storage systems as regulators allows for the sustainable integration of renewable energy resources into the electrical grid. Vanadium redox flow batteries (VRFBs) are the most promising candidates of the currently available energy storage technologies, as they have an unlimited capacity (theoretically) and design flexibility. Enhancing the kinetics of the VRFBs electrochemical reactions will enhance their energy efficiency, and hence decrease the kWh cost of VRFBs. Currently, carbon-based electrodes are employed due to their suitable stability and conductivity, but with no treatment, they suffer from sluggish kinetics, hydrophobicity, and parasitic reactions catalyzation.1 Modifying these carbon-based electrodes with carbon nanostructures2 and metal oxides(MOx)3 was found to enhance the kinetics at the VRFB electrodes. Even though fullerenes have very unique structural and chemical properties they were rarely explored for the VRFBs application.4 In this work, fullerene C76 showed superior electrocatalytic activity towards VO2+/VO2 + redox reaction in G1 and G3 VRFBs and eliminated the necessity for thermal treatment of the carbon cloth support while inhibiting the chlorine evolution in G3 VRFB. A composite of C76 and hydrated WOx that reduces the fullerene content to half further inhibited the chance for chlorine evolution while maintaining the catalytic activity. References: Y. Gao et al., Carbon, 148, 9–15 (2019). D. O. Opar, R. Nankya, J. Lee, and H. Jung, Electrochimica Acta, 330, 135276 (2020). M. Faraji, R. Khalilzadeh Soltanahmadi, S. Seyfi, B. Mostafavi Bavani, and H. Mohammadzadeh Aydisheh, J Solid State Electrochem, 24, 2315–2324 (2020). F. A. E. Diwany, B. A. Ali, E. N. E. Sawy, and N. K. Allam, Chem. Commun., 56, 7569–7572 (2020).