Application of Pt loaded graphite felt in SO2-depolarized electrolyzer

The three-dimensional anodes for SO2 depolarized electrolysis (SDE) cells are prepared by loading Pt/C on high void content graphite felts, with the method of ultrasonic spray and vacuum suction. SEM results confirm the three-dimensional space distribution of Pt in graphite felts, which ensures sufficient contact between Pt/C and SO2 in anolyte. Comparing with the two-dimensional anodic catalyst layer loaded on the proton exchange membrane in a conventional SDE cell, the application of the three-dimensional anode decreases cell impedance greatly and improves the SDE performance significantly. In this study, 0.63 mg/cm2 Pt loading amount shows the best performance when Pt/C is double-side-sprayed on graphite felt, and the current density reaches 1.24 A/cm2 at cell voltage of 1.2 V, as operating at 60 °C and anolyte flow rate of 360 mL/min. The effects of the Pt loading amount, operating temperature and anolyte flow rate on the SDE performance are investigated.