There is a great interest in the development of advanced electrocatalysts for efficient water splitting. A tantalum iridium oxide (Ta2O5-IrO2) coating is considered to be one of the best electrocatalysts for the oxygen evolution reaction (OER) in acidic media. In the present study, novel Ta2O5-IrO2-rGO coatings with varying loads of reduced graphene oxide (rGO) were designed to investigate the effects of rGO on the catalytic activity and stability of the Ta2O5-IrO2 coating for the OER. Five different electrodes comprised of Ta2O5-IrO2-rGO on a titanium substrate were fabricated with incremental weight percentages of rGO (0.0 wt.%, 1.0 wt.%, 2.0 wt.%, 5.0 wt.% and 7.5 wt.%) using a facile thermal decomposition method. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS) were employed to characterize the morphology and composition of the prepared Ta2O5-IrO2-rGO coatings. Longevity tests revealed that the incorporation of rGO into the oxide layer strongly affected the stability of the Ta2O5-IrO2-rGO electrodes. The electrochemical activities of the prepared Ta2O5-IrO2-rGO electrodes were characterized by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The Ta2O5-IrO2-rGO coating containing 1.0 wt.% rGO exhibited the greatest stability, along with enhanced OER activity.

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There is significant interest in the design of high-performance electrocatalysts for efficient electrochemical reduction of CO2 to address the pressing environmental issue and climate change. Herein, a novel copper–aluminum nanostructured catalyst is fabricated via an alloying/dealloying technique. The effect of the initial alloy’s elemental composition and subsequent dealloying, via HCl acid treatments, on the stability and activity of the catalyst for electrochemical CO2 reduction is studied. The optimized porous catalyst shows high catalytic activity for the electrochemical CO2 reduction reaction (CO2RR) with current efficiencies achieving greater than 81%. Gas and liquid product analysis confirms the formation of CO, H2, and HCOO–. Scanning electrochemical microscopy was employed to monitor the activity of the catalyst and the CO2RR products. In situ electrochemical FTIR spectroscopic studies revealed the first CO2RR intermediate was carbon-bound to the acid-treated 50:50 Cu/Al (at. %) alloy surface in a monodentate orientation. The synthetic approach reported in the present study leads to a new promising electrocatalyst with superior catalytic activity and high efficiencies for the effective electrochemical reduction of CO2 to valuable products.

In order to sustain and support the current level of economic growth, while addressing climate change issues, the development of clean and sustainable resources has become of the utmost importance in recent years. Potential resources such as oxygen and hydrogen can be produced from water electrolysis. There is a great interest in the development of advanced electrocatalysts for efficient water splitting [1,2]. Two-dimensional (2D) nanomaterials like graphene and graphene oxide (GO) can form thin layers on a supporting material for the transformation of properties and, as a result, can be exploited for efficient oxygen evolution reaction (OER) catalysts [3]. Previous research shows that noble metals tend to have a good catalytic activity for the OER; while another metal is added to further improve the electrochemical stability of the catalytic layer. By incorporation of a 2D graphene-based nanomaterial into an established OER electrocatalyst, there is significant potential to improve the OER catalytic activity and stability. A tantalum iridium oxide (Ta2O5-IrO2) coating is considered to be one of the best electrocatalysts for the OER in acidic media. In the present study, novel Ta2O5-IrO2-rGO coatings with varying loads of reduced graphene oxide (rGO) were designed to investigate the effects of rGO on the catalytic activity and stability of the Ta2O5-IrO2 coating for the OER. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS) were employed to characterize the morphology and composition of the prepared Ta2O5-IrO2-rGO coatings. Longevity tests revealed that the incorporation of rGO into the oxide layer strongly affected the stability of the Ta2O5-IrO2-rGO electrodes. The electrochemical activities of the prepared Ta2O5-IrO2-rGO electrodes were characterized by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). The effect of graphene-based nanomaterials on a Ta2O5-IrO2-rGO coating is compared and discussed. [1] B. Sidhureddy, J. S. Dondapati, and A. Chen, Chem. Commun., 55, 3626 (2019). [2] J. Cirone, S. R. Ahmed, P. C. Wood, and A. Chen, J. Phys. Chem. C, 123, 9183 (2019). [3] A. Salverda, J.S. Dondapati, A. R. Thiruppathi, and A. Chen, J. Electrochem. Soc., 167, 146506 (2020).

Increasing energy demand is inexorably linked to the need for efficient energy storage techniques. For practical applications, it is highly desirable to decrease the size of electrical components and to increase the storage capacities while maintaining power, stability, and charging-discharging speeds. Much focus has been directed towards the development of supercapacitors. These are often fabricated from carbonaceous or metal oxide materials with high surface areas to maximize electrode/electrolyte interactions. The use of nanostructured TiO2 electrodes has been explored for this application due to their low cost, high stability, and highly tunable morphology. Here we present the fabrication of nanostructured TiO2 films via a facile anodic process. Characterization of the films was carried out by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Electrochemical reduction of the formed TiO2 film was further performed to increase its capacitance, which was confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. The performance of the symmetric capacitor constructed with the modified TiO2 films will be presented.