Investigation of electrochemical performance of an efficient Ti_2O_3-CeO_2 nanocomposite for enhanced pollution-free energy conversion applications

摘要

The development of an economical, abundant, stable, and greatly active electrocatalyst for water oxidation is extremely important for future energy conversion system. Electrochemical water splitting is a new move toward H_2 and O_2 gas production. It can be used in sustainable and pollution-free energy conversion applications. In this work, Ti_2O_3-CeO_2 nanocomposites were successfully synthesized with different molar ratios by facile hydro-thermal method for electrochemical water oxidation. Mixed phase structure of Ti_2O_3-CeO_2 nanocomposites was confirmed by X-ray diffraction spectra and well identified by highest peak of Ti_2O_3 in 20 values of 33.0 and CeO_2 in 20 values of 28.5. The characteristic peaks from Raman and photoluminescence spectroscopy further confirmed Ti_2O_3-CeO_2 nanocomposite formation. Existence of multidimensional nanostructures such as nano-particles and small nanocubes of Ti_2O_3-CeO_2 nanocomposites were investigated by scanning electron microscope images. Mesoporous nature of Ti_2O_3-CeO_2 nanocomposites was further analyzed by Brunauer-Emmett-Teller analysis. The high surface area could benefit the Ti_2O_3-CeO_2 nanocomposites with greatly improved oxygen evolution reaction (OER) performance. In three molar ratios, 1:3 M ratios of Ti_2O_3-CeO_2 nanocomposites showed high catalytic action at overpotential of 244 mV. The best OER electrocatalyst was obtained by 1:3 M ratios of Ti_2O_3-CeO_2 nanocomposites, which exhibited high current density and high specific capacitance values of 238 mA/g and 517 F/g, respectively. Therefore, Ti/Ce molar ratio played a crucial role in enhancing the OER performance.