A carbon-supported Rh phthalocyanine catalyzed the electro-oxidation of glucose in basic solution. The overpotentials for the oxidation are lower than those with other conventional Co phthalocyanine-based catalysts. This electrocatalytic oxidation is coupled with the redox potential of Rh phthalocyanine. The introduction of an electron-donating group causes negative shift in the redox potential, and decreases the onset potential for the oxidation of glucose. The Rh phthalocyanine catalyst needs activation before the catalytic oxidation of glucose. This activation is achieved by the exposure of the catalyst to negative potentials. This catalyst also oxidizes gluconate, which is a possible 2-electron oxidation product of glucose. Electrolysis of glucose solution shows that glucose undergoes multi-electron (more than 2) oxidation by the Rh phthalocyanine. (C) 2016 Elsevier B.V. All rights reserved.