Ru@Pt/C core-shell catalyst for SO2 electrocatalytic oxidation in electrochemical Bunsen reaction

Abstract

Although SO2 is a highly toxic industrial pollutant, it can be used as a potential source of hydrogen and H2SO4 in the presence of water. This characteristic of SO2 is widely applied in desulfurization of industrial flue gas, hybrid-sulfur cycle and sulfur-iodine cycle. The main way to advance this technology is to develop a suitable electrocatalyst. So far researches on electrocatalysts for liquid phase oxidation of SO2 mainly focus on noble metal, which have excellent corrosion resistance and catalytic activity in acidic environment. In order to improve the performance of Pt-catalysts in SO2 electrocatalytic oxidation and reduce the use of Pt, a series of Ru@Pt/C core-shell catalysts with different Ru/Pt molar ratios were synthesized by microwave-assisted alcohol reduction. Reduction in the size of Pt shell is beneficial to increase the catalytic activity brought by the electronic effect. The bi-functional effect of Ru and Pt is more pronounced in the case of low Pt coverage. Ru only plays an auxiliary role and does not have the property of direct catalytic oxidation of SO2. The results showed that the optimal mass activity was achieved when Ru/Pt was 1:1. While when Ru/Pt was 3:1, the unit mass activity of Pt was the highest, which was 3.97 times of Pt/C.