A facile template-free hydrothermal method was applied to successfully synthesize a series of bulk cobalt oxides with different morphologies (1D-Co₃O₄ nanoneedle, 2D-Co₃O₄ nanoplate, and 3D-Co₃O₄ nanoflower). The catalytic activity for the toluene combustion over various types of catalysts was investigated. The 3D-Co₃O₄ nanoflower performed the excellent activity and the temperature required for achieving a toluene conversion of 90 % (T_90%) at approximately 238 °C with the activity energy (E_a) of 71.6 KJ mol⁻¹, which was 19 ℃ lower than that of 1D-Co₃O₄ nanoneedle with E_a of 97.1 KJ mol⁻¹ at a space velocity (WHSV = 48, 000 mL g⁻¹ h⁻¹). The effect of shape on the physicochemical properties of the Co₃O₄ catalysts were characterized by various analytical techniques. It has been found that large specific surface area, low temperature reducibility, highly defective structure with abundant surface active oxygen species and rich Co³⁺ cationic species were responsible for the excellent catalytic performance of 3D-Co₃O₄ nanoflower. In addition, complete conversion of toluene had remained the same after 3D-Co₃O₄ nanoflower was observed for 120 h, suggesting it exhibited the long-term stability for toluene combustion. Therefore, 3D-Co₃O₄ nanoflower might be a potential non-noble catalyst in practical application.

应用一种简便的无模板水热法成功合成了一系列具有不同形态的块状氧化钴（1D-Co ₃ O ₄纳米针，2D-Co ₃ O ₄纳米板和3D-Co ₃ O ₄纳米花）。研究了在各种类型的催化剂上甲苯燃烧的催化活性。3D-Co ₃ O ₄纳米花表现出出色的活性和在约238°C下达到90％（T _90％）的甲苯转化率所需的温度，其活性能（E _a）为71.6 KJ mol ^-1，这比1D钴的低19℃ ₃ ö ₄与纳米针ë_一个97.1 KJ摩尔^-1空间速度（WHSV = 48，000毫升克^-1 ħ ^-1）。通过各种分析技术表征了形状对Co ₃ O ₄催化剂的物理化学性质的影响。已经发现，大的比表面积，低温还原性，具有大量表面活性氧种类和丰富的Co ³⁺阳离子种类的高度缺陷的结构是3D-Co ₃ O ₄优异的催化性能的原因。纳米花。此外，在观察3D-Co ₃ O ₄纳米花120小时后，甲苯的完全转化率保持不变，这表明它表现出了甲苯燃烧的长期稳定性。因此，在实际应用中，3D-Co ₃ O ₄纳米花可能是潜在的非贵金属催化剂。