Mechanistic study of glucose oxidation on copper sulfide modified glassy carbon electrode

By studying the reduction of hydrogen peroxide and oxidation of glucose on the CuS nanoparticles modified glassy carbon electrode (CuS/chitosan/GCE), a mechanism of the oxidation of glucose was proposed. It was believed that there is no direct electron transfer between glucose and the electrode surface. Although CuS is a weak oxidant, the glucose was oxidized by CuS while Cu(II) was reduced to Cu(I). The produced Cu(I) undergoes two competing reactions. One reaction is the electro-oxidation of Cu(I) to Cu(II) on the electrode surface which induces the increase of the anodic peak current of the Cu(II)/Cu(I) redox couple in the presence of glucose. Another is the oxidation of Cu(I) by dissolved oxygen to produce H2O2 which was subsequently reduced on the electrode surface.