Catalytic electrogenerated chemiluminescence and nitrate reduction at CdS nanotubes modified glassy carbon electrode.

Electrochemical and electrogenerated chemiluminescence (ECL) properties of a glassy carbon electrode modified with CdS nanotubes (CdS−GCE) are investigated in neutral media. The cyclic voltammogram (CV) shows two cathodic peaks (PC1 and PC2) at −0.76 and −0.97 V and an anodic peak (PA) at −0.8 V, while two ECL peaks around −0.76 V are observed. Similar mechanisms of both ECLs are supposed and possibly related to the capture of an electron at a surface trap, that is, the surface sulfide vacancy (VS2+) of CdS nanotubes and its electrocatalytic reduction to H2O2 generated from the dissolved oxygen. PC2 and PA are ascribed to the two-electron redox at VS2+. Moreover, electrocatalysis to nitrate reduction is also found at PC2, with a good linear relationship between nitrate concentration and electrocatalytic peak current in CV.