Synthesis and size-dependent electrochemical nonenzymatic H2O2 sensing of cuprous oxide nanocubes

In this work, we reported an electrochemical approach for the nonenzymatic detection of H 2 O 2 based on a cuprous oxide (Cu 2 O) nanocube-based sensor. The Cu 2 O nanocubes were synthesized with controllable sizes from 40 nm to 360 nm through a facile additive-free aqueous solution route at room temperature. The electrocatalytic activities of the Cu 2 O nanocubes with five different sizes towards H 2 O 2 were systematically explored, and it was found that the electrocatalytic activity was strongly dependent on the size of the Cu 2 O nanocubes. The cyclic voltammetry and amperometry results show that these Cu 2 O nanocubes exhibited good electrocatalytic activity with a linear response ranging from 0.5 to 8.5 mM at −0.2 V and a detection limit of 1.61 μM (S/N = 3). Furthermore, the Cu 2 O nanocubes of five different sizes have good selectivity for H 2 O 2 detection with ascorbic acid (AA), uric acid (UA) and glucose (Glu). The smaller size Cu 2 O nanocubes can effectively increase the electrocatalytic active areas and subsequently promote electron transfer in the reduction of H 2 O 2 .