Improving Nickel Diselenide Performance toward Oxygen Reduction Reaction with Ruthenium Incorporation and Heat Treatment

A small amount of ruthenium (Ru) was introduced into carbon supported nickel diselenide (NiSe2/C) through a simple microwave route to obtain Ru incorporated ternary catalyst Ru(NiSe2)/C. A comparative study was performed without and with the heat treatment to examine the crystal phases, microstructures, electrocatalytic activities and stabilities toward oxygen reduction reaction (ORR) for binary NiSe2/C and ternary Ru(NiSe2)/C. The results revealed that the half-wave potential (E (1/2)) of the best performed Ru(NiSe2)/C-400 reached 0.64 V with the overall loss of 5.6% in E (1/2) after 1000 cycles in 0.1 mol center dot l(-1) HClO4, showing the highly improved ORR activity and excellent stability as compared with those of the best performed NiSe2/C-350. When tested as a cathode catalyst in the H-2/O-2 single cell at 65 degrees C and ambient pressure, the open circuit potential and the maximum power density approached 0.78 V and 132 mW center dot cm(-2), respectively. The achieved mass activity of 0.08 mA center dot(mu g Ru)(-1) at 0.75 V was comparable to that of Ru(CoSe2)/C-400 (0.09 mA center dot(mu g Ru)(-1)). The simultaneous enhancement in the ORR activity and stability of Ru(NiSe2)/C in an acid electrolyte might be mainly contributed by a new stable (Ru, Ni)Se-2 like structure. Furthermore, selenium evaporation and grain growth could be effectively prevented during the heat treatment by Ru incorporation.