The slow redox rate of hydrogen peroxide (H2O2) in neutral environments makes the H2O2 sensor inadequate for the detection of low levels of signalling molecules. The aim of this study is to fabricate a flexible sensing electrode by hydrothermally loading micro-nanometer Ni and Co(OH)2 on carbon cloth (CC) and electrochemically depositing poly(3,4-ethylenedioxythiophene) (PEDOT) on the surface of the electrode. The sensor presented high sensitivity (10.43 mA mM−1 cm−2), a wide detection range (0.033–120.848 mM), a low detection limit (0.92 nM), high stability, and excellent anti-interference performance in neutral solutions. Ni–Co(OH)2 provides abundant active sites while CC solves their agglomeration phenomenon and conductivity. The PEDOT film offers heightened conductivity, hydrophilicity, interfacial stability, and an electrochemically active surface area (ECSA). The side area of the chrysanthemum petal like PEDOT is 39 ± 7 times the bottom area, and PEDOT increases the ECSA of the composite to six times that of CC. Electrochemical precise control of PEDOT morphology to improve sensor performance provides a new strategy for the application of PEDOT in sensors.
Surface microstructure regulation is an effective way to enhance the performance of sensing materials. Here, a hierarchical and flexible Brussels sprout-like Ni–Co(OH)2/rGO/carbon cloth (CC) composite was constructed by optimizing the morphology of Ni–Co(OH)2 microspheres and the addition amount of rGO. This sensor shows excellent reproducibility, high selectivity, and good stability. It shows a high sensitivity of 3.7391 mA mM−1 cm−2 in the 0.0388–124.0436 mM line detection range for H2O2 and 1.8457 mA mM−1 cm−2 in the 0.0300–2.0000 mM line detection range for glucose. The low limits of detection for H2O2 and glucose are 2.316 nM and 0.115 μM, respectively. The excellent electrochemical performance of the Ni–Co(OH)2/rGO/CC composite is attributed to its unique Brussels sprout-like microstructure. By studying the electrical conductivity, electrochemical active surface area, and hydrophilic–hydrophobic surfaces of the Ni–Co(OH)2/rGO/CC composite, the structure–performance relationship between the microstructure and sensing performance of the composite was further clarified. Moreover, the mechanism of CC, rGO, and the Ni–Co(OH)2 ternary composite in the sensing process is proposed. This study provides a new strategy for the construction of flexible wearable electrodes with high sensitivity.
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