Harvesting high-performance electro-water oxidation and selective MB degradation through dual functional Gd2O3–La2O3 photo-electrocatalysts

Abstract

Interestingly, catalytic oxygen evolution reaction (OER) in an alkaline medium with minimizing the overpotential is the most trustworthy electrocatalyst for the output of hydrogen energy from copious water electrochemical activity. Currently, amalgamated trivalent cations metal oxides have gained desirability as a low-cost anode electrocatalyst to replace noble metal-supported electrocatalysts for water oxidation and are also used for photo-degradation applications. In the present work, we have successfully synthesized GdO supported LaO composites via hydrothermal pathways for efficient and selective methylene blue (MB) degradation applications. XRD, UV–Vis DRS, FT-IR, XPS, SEM-EDX, HR-TEM, DLS, and BET analyzers confirmed the successful synthesis of photo-electrocatalysts. GdO–LaO composites achieved 5.66 and 3.37-fold larger surface areas than LaO and GdO, respectively. The results of the GdO supported LaO composite electrode demonstrated better performance under 1 M , and it exhibited a lower Tafel slope and overpotential of 72 mV dec and 310 mV at 10 mA cm. A chronoamperometry examination confirms that the fabricated GdO–LaO electrode has good stability at a fixed potential of 1.540 V vs. RHE for water oxidation. Although the, Gd inspired LaO electrode actively takes part in OER activity owing to its high C value of 40.222 μF cm. The selective degradation of MB dye using the GdO–LaO composite achieved an acceptable degradation efficiency of 84.80 % compared to other pollutants under UV-light irradiation for 120 min, and the specified pH condition is 9 for the degradation of MB dye, and it follows the first-order kinetics model. Notably, post-OER and photocatalytic results exhibited good stability and reusability characteristics. Therefore, the GdO–LaO catalyst can be used for real-time water oxidation and MB dye removal from polluted water.