Microbial electrochemical cells (MECs) are explored for the conversion of acetate directly to electrical energy. This device utilizes a Geobacter sulfurreducens anode and a novel RuCoSe air cathode. RuCoSe synthesized in selected compositions by a borohydride reduction method produces amorphous structures of powdered agglomerates. Oxygen reduction reaction (ORR) was measured in a phosphate buffer solution pH 7 using a rotating disc electrode (RDE), from which the kinetic current (i(k)) was measured as a function of potential and composition. The results show that ik of RuxCoySe catalysts increases in the range of X-Ru = 0.25 > x > 0.7 and y < 0.15 for all tested potentials. A poisoning study of RuCoSe and Pt catalysts in a high concentration acetate solution shows improved tolerance of RuCoSe to this fuel at acetate concentration >= 500 mM. MEC discharge plots under physiological conditions show that similar to RuCo2Se (sample S3) has a peak power density of 750 mW cm(-2) which is comparable with Pt 900 mW cm(-2). (C) 2017 Elsevier B.V. All rights reserved.