ABSTRACT
Direct electrochemical oxidation of sugars is of great importance for several points of view ranging from biomedical (blood sugar analysis) and fuel cell applications to ecological approaches (wastewater treatment) (Meng et al., 2009; Newman & Turner, 2005; Shoji & Freund, 2001; Wu et al., 2007; You et al., 2003). The detection of glucose level in the blood is a challenging task from diagnostic and therapy of diabetics. The electrochemical biosensors have been applied successfully for the determination of glucose (Fu et al., 2009; Gopalan et al., 2009; Sheng et al., 2009; Tasviri et al., 2011; Wu et al., 2009; Yang et al., 2011; Hongfang Zhang et al., 2011). Some of the electrodes like platinum (de Mele et al., 1983), copper (Hampson et al., 1972; Luo & Baldwin, 1995; Torto et al., 1999), nickel (Fleischmann et al., 1971, 1972) and gold (Matsumoto et al., 2003; Parpot et al., 2006), and also on modified surfaces such as ruthenium dioxide (Joseph Wang & Taha, 1990), nickel oxide (Berchmans et al., 1995; Vidotti et al., 2009), cobalt oxide (Buratti et al., 2008), alloy (Yeo & Johnson, 2001) and metallic complexes such as cobalt phthalocyanine (Santos & Baldwin, 1987) have been explored to investigate the direct electrochemical oxidation of sugars in alkaline medium. Among the various possible electro-catalysts, nickel hydroxide has attracted much attention specifically as a fuel cell catalyst, secondary batteries and electrocatalyst for organic synthesis (Burda et al., 2005; Daniel & Astruc, 2003). Its unique electro-catalytic effect arises from the unpaired ‘d’ electrons and vacant ‘d’ orbitals associated with the oxidized form of nickel oxyhydroxide that are readily available to bind any adsorbed species (Lo & Hwang, 1995).
