Abstract Exploring of an efficient and cheap-cost peroxidase mimic is crucial for constructing a colorimetric sensing platform. Herein, a series of Ag-decorated CoO nanoparticles (Ag-CoO NPs) were synthesized by a facile one-pot solvothermal strategy and followed by heat treatment. The compositions and morphologies of the as-prepared catalysts were characterized by XRD, N2-adsorption/desorption, SEM, TEM, XPS, UV–vis diffuse reflectance and transient photocurrent techniques. The core-shell structured 0.10Ag-CoO NPs (molar ratio of AgNO3/Co(NO3)2 = 0.10) with high dispersion possess large specific surface area (156.8 cm2 g−1) and rich mesoporous structure, thus providing more catalytic active sites. Suitable Ag decoration not only increases the surface active oxygen species and strengthens the visible light respond but also improves the separation of photo-generated electron–hole pairs of 0.10Ag-CoO NPs. As a result, 0.10Ag-CoO NPs exhibit superior peroxidase-like activity for 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation in the presence of H2O2 compared to pure CoO NPs and the other nanoparticles. Then a sensitive and selective colorimetric sensing platform was constructed for detecting hydrogen peroxide and o-phenylenediamine. Finally, the possible catalytic mechanism was also proposed here.

中文翻译：

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核壳结构的Ag-CoO纳米颗粒具有优异的过氧化物酶样活性，用于比色传感过氧化氢和邻苯二胺

摘要 探索一种高效廉价的过氧化物酶模拟物对于构建比色传感平台至关重要。在此，通过简单的一锅溶剂热策略合成了一系列 Ag 装饰的 CoO 纳米颗粒（Ag-CoO NPs），然后进行热处理。通过 XRD、N2 吸附/解吸、SEM、TEM、XPS、UV-vis 漫反射和瞬态光电流技术表征所制备催化剂的组成和形貌。具有高分散性的核壳结构 0.10Ag-CoO NPs（AgNO3/Co(NO3)2 的摩尔比 = 0.10）具有较大的比表面积（156.8 cm2 g-1）和丰富的介孔结构，从而提供更多的催化活性位点. 合适的银装饰不仅增加了表面活性氧物质并增强了可见光响应，而且改善了 0.10Ag-CoO NPs 的光生电子 - 空穴对的分离。因此，与纯 CoO NPs 和其他纳米颗粒相比，0.10Ag-CoO NPs 在 H2O2 存在下对 3,3',5,5'-四甲基联苯胺 (TMB) 氧化表现出优异的过氧化物酶样活性。然后构建了一个灵敏、选择性的比色传感平台，用于检测过氧化氢和邻苯二胺。最后，这里还提出了可能的催化机制。与纯 CoO NPs 和其他纳米粒子相比，在 H2O2 存在下的 5'-四甲基联苯胺 (TMB) 氧化。然后构建了一个灵敏、选择性的比色传感平台，用于检测过氧化氢和邻苯二胺。最后，这里还提出了可能的催化机制。与纯 CoO NPs 和其他纳米粒子相比，在 H2O2 存在下的 5'-四甲基联苯胺 (TMB) 氧化。然后构建了一个灵敏、选择性的比色传感平台，用于检测过氧化氢和邻苯二胺。最后，这里还提出了可能的催化机制。