Co₃O₄ nanomaterials with diverse morphologies were usually synthesized in liquid phase accompanied by the template or surfactant under harsh conditions, which further restricted their practical application. Herein, we reported an extremely simple and practical solid-state chemical method to synthesize Co₃O₄-octahedrons, -plates, and -rods. Among these, the shape control of Co₃O₄-octahedrons and Co₃O₄-plates involve variation of the amount of reactant, and the formation of Co₃O₄-rods with {110} facet can be achieved by replacing the reactant. The formation of the Co₃O₄ nanomaterials with different morphologies originated from the different microenvironments of reaction and the structure of reactants. The catalytic activity of Co₃O₄ samples for CO oxidation was evaluated in normal feed gas. The as-prepared Co₃O₄-rods exposed {110} facet exhibited superior catalytic activity for CO oxidation, which can be attributed to more oxygen defects on Co₃O₄-rods surface. Additionally, Co₃O₄-rods exhibited excellent durablility (without pretreatment) in normal feed gas, even in the presence of moisture, comparable or better than that reported in the literature. The practical and environmental friendly solvent-free strategy provided a new promising route for large-scale preparation of (metal) oxide with remarkable CO oxidation performance for practical application.

中文翻译：

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无溶剂化学法合成多种形态的Co ₃ O ₄用于CO氧化

通常在苛刻条件下，伴随模板或表面活性剂在液相中合成具有多种形貌的Co ₃ O ₄纳米材料，这进一步限制了它们的实际应用。在此，我们报道了一种非常简单实用的固态化学方法，用于合成Co ₃ O _4-八面体，-板和-棒。其中，Co ₃ O ₄八面体和Co ₃ O ₄板的形状控制涉及反应物量的变化，并且可以通过替换反应物来实现{110}面的Co ₃ O ₄棒的形成。。Co ₃的形成具有不同形态的O ₄纳米材料源自不同的反应微环境和反应物的结构。在正常进料气中评估了Co ₃ O ₄样品对CO氧化的催化活性。暴露的{110}小平面上制备的Co ₃ O ₄棒表现出优异的CO氧化催化活性，这可以归因于Co ₃ O ₄棒表面上更多的氧缺陷。另外，Co ₃ O ₄棒即使在存在水分的情况下，在正常进料气中也表现出出色的延展性（未经预处理），与文献报道的相当或更好。实用且环境友好的无溶剂策略为大规模制备具有卓越的CO氧化性能的（金属）氧化物提供了新的有希望的途径，以供实际应用。