Highly Stable and Methanol Tolerant RuTe2/C Electrocatalysts for Fuel Cell Applications

Carbon supported ruthenium tellurium (RuTe2/C) catalysts were synthesized with various Ru/Te ratios (2:1, 1.5:1, 1:1, 1:2, and 1:3) via a microwave route followed by heat-treatment. Effects of Ru/Te ratio on crystal structures, microstructures, chemical states and electrocatalytic activities toward oxygen reduction reaction (ORR) of RuTe2/C were systematically investigated. A mixed phase with predominant orthorhombic RuTe2 and minor hexagonal Ru was identified. A novel synergistic effect was provided by RuTe2 and Ru which acted as dual ORR active sites. The average particle sizes ranged 5.0 similar to 8.4 nm, while the half-wave potentials (E-1/2) varied 0.57 similar to 0.61 V in HClO4 and 0.70 similar to 0.72 V in KOH as the Ru/Te ratios changed from 2:1 to 1:3. The largest E-1/2 values of 0.61 V and 0.72 V, as well as the E-1/2 losses of 0.83% and 0.69% upon 1000 cycles or 3.28% and 0.97% (containing 2 mol . L-1 methanol) were obtained for the RuTe2/C (Ru/Te = 1:1) in HClO4 and KOH, respectively, showing the best ORR activity and excellent stability with high methanol tolerance in both acidic and alkaline media. The preliminary cell performance revealed the maximum power density of 269 mW . cm(-2) with impressive durability. (C) 2018 The Electrochemical Society.