Mass transfer plays a significant role in a sensor's performance, because the substrate can be detected only when it contacts with the active catalytic surface. In this work, cuprous oxide mesoporous nanospheres (Cu₂O MPNS) with different pore size distributions are fabricated and applied as electrocatalysts for glucose detection. The small pore Cu₂O (SP-Cu₂O, mean pore size of 5.3 nm) and large pore Cu₂O (LP-Cu₂O, mean pore size of 16.4 nm) spheres are prepared by the template method and an etching treatment. The obtained two kinds of Cu₂O MPNS exhibit high porosity with a similar specific surface area of 61.2 and 63.4 (m²·g-1), respectively. The prepared Cu₂O MPNS are used to construct an electrochemical non-enzymatic glucose sensor. The results show that the LP-Cu₂O exhibits better performance than SP-Cu₂O, which illustrates that the internal diffusion takes a great impact on the performance of the sensor. The LP-Cu₂O modified electrode possesses a high and reproducible sensitivity of 2116.9 μA mM-1·cm-2 at the applied potential of 0.6 V with a wide detection range of 0.003-7.8 mM and a low detection limit of 0.42 μM.
Keywords: cuprous oxide; glucose; internal diffusion; mesoporous spheres; non-enzymatic sensor.