Energy-saving synthesis of electrolytic manganese dioxide using oxygen cathode with Pt/TiO2-CNx nanocatalysts

Abstract

The awareness of energy, environment, and economy for electrolysis has required the development of new methods to prevent environmental pollution, such as the emission of acid fog, CO2, and SO2. Hence, the use of gas diffusion electrode as a cathode in the electrodeposition of manganese dioxide to save energy and protect the environment is attracting research interest. In this work, a gas diffusion electrode consisting of a mixture of Pt/TiO2-CNx nanocatalysts and two different additive conductor supports that activate carbon and acetylene black were synthesized. The Pt/TiO2-CNx nanocatalysts and Pt/TiO2-CNx gas diffusion electrode were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The Pt/TiO2-CNx nanowire catalyst showed strong interaction between the Pt nanoparticles (~2.21 nm) and TiO2-CNx nanowire support. Results of electrochemical tests in 120 g of MnSO4 + 30 g of H2SO4 at 80 °C show that the Pt/TiO2-CNx gas diffusion electrode used in the electrodeposition of manganese dioxide could save electric energy by approximately 60%. Furthermore, the lifetime of the gas diffusion electrode of Pt/TiO2-CNx nanocatalysts was about twofold longer than that of the gas diffusion electrode of Pt/C and Pt/TiO2 nanocatalysts. The Pt/TiO2-CNx nanowire catalyst exhibited high anti-acid corrosion, activity, and stability, indicating its potential important application in the electrodeposition of manganese dioxide.