For enhance the electrochemcial performance of URFC system, the novel combination of sulfonated silica-supported Pt electrocatalyst were synthesized. The investigated electrochemical surface area values are 23.02 and 22.96 m²/g for the Pt black and 80 wt% Pt/SiO₂-SO₃H catalysts, respectively. The bifunctional (oxygen reduction reaction (ORR) and oxygen evolution reaction (OER)) performance in URFC system were carried out through fuel cell and water electrolyzer modes for Pt/C, Pt/SiO₂, and Pt/SiO₂-SO₃H electrocatalysts. The determined round-trip energy conversion efficiency of Pt/C, Pt/SiO₂, and Pt/SiO₂-SO₃H are 45.3, 44.6 and 46.1 %, respectively. Comparatively, the Pt/SiO₂-SO₃H electrocatalyst shows an improved electrocatalytic performance than Pt/C and Pt/SiO₂ electrocatalysts. Due to presence of sulfonic acid functional group on the support material (SiO₂–SO₃H), the proton conduction has intensified in the catalyst layer during the URFC unit cell operation. Based on the performance data, the sulfonated silica-supported Pt electrocatalyst (Pt/SiO₂-SO₃H electrocatalyst) identified as a efficient bifuntional electrocatalyst material for further development in URFC applications.

Key Words : Unitized regenerative fuel cell (URFC), Electrocatalyst, Sulfonated silica (s-SiO₂), Oxygen reduction reaction (ORR)