Probing the crystal plane effect of Co3O4 for non-enzymatic electrochemistry sensing performance toward hydrogen peroxide

The crystalline structure of catalyst surfaces has an important effect on the catalytic activity. However, the crystal plane effects of Co 3 O 4 catalysts towards H 2 O 2 activation are rarely reported. In this work, Co 3 O 4 hexagon nanosheets, nanosheets, nanorods and nanocubes with respective {1   1   1}, {1   1   2}, {1   1   0} and {0   0   1} dominant exposed facets were synthesized by hydrothermal synthesis, and the crystal plane effects of these Co 3 O 4 nanocrystals were compared with respect to their viability as potential for non-enzymatic H 2 O 2 sensors. Co 3 O 4 as a hexagonal nanosheet with a {1   1   1} crystal plane exhibited the best performance for H 2 O 2 detection, and exhibited a fast response of 3 s, a wide linear range from 0.0005 ∼ 8.5 mM with sensitivity of 1160.2 μA·mM -1 cm - 2 , and detection limit of 0.049 μM. Overall, the H 2 O 2 detection performance of Co 3 O 4 with different exposed facets was ranked as {1   1   1} > {1   1   2} > {1   1   0} > {0   0   1}, which is consistent with the proportion of surface Co 3+ , indicating that the surface Co 3+ exhibit higher activity for H 2 O 2 oxidation. This study indicates that tuning of thecrystal plane of nanocrystals is important to enhancement of non-enzymatic H 2 O 2 detection, and provides an important constraint when developing high efficiency catalysts for non-enzymatic electrochemical H 2 O 2 sensors.