淬火法处理β-MnO2纳米棒及其选择性催化氧化肉桂醇性能

    Quenching-treated β-MnO2 Nanorods: Enhanced Catalytic Performance in Selective Oxidation of Cinnamyl Alcohol

    • 摘要: 本文以β-MnO2纳米棒为前驱体,通过采用简单的淬火方法,成功获得了富含表面氧空位的β-MnO2纳米棒,并将其应用在选择性氧化肉桂醇合成肉桂醛反应。通过改变煅烧温度,研究了淬火后β-MnO2纳米棒的表面结构对其催化活性的影响。结果表明,淬火处理得到的β-MnO2纳米棒的催化活性明显优于β-MnO2纳米棒前驱体和煅烧后自然冷却的β-MnO2纳米棒,其中,350 ℃煅烧并快速冷却的β-MnO2纳米棒具有最好的催化活性,其肉桂醇转化率和肉桂醛选择性分别为53.1%和95.2%,而且高于多种商用非贵金属氧化物。结合多种表征结果可知,淬火技术有助于提升β-MnO2纳米棒的表面晶格氧活性及其氧化能力,从而有效提高其催化氧化性能。本工作表明淬火技术对提高MnO2表面氧空位浓度和催化性能具有积极作用,这为设计高效的非贵金属氧化物催化剂提供了一种有效策略。

       

      Abstract: In this research, β-MnO2 nanorods enriched with surface oxygen vacancies were successfully fabricated through a facile quenching strategy using pristine β-MnO2 nanorods as the precursor. The quenched samples were applied as the catalysts for the selective oxidation of cinnamyl alcohol to cinnamaldehyde. By varying the calcination temperature, the influence of surface structure of quenched β-MnO2 nanorods on their catalytic performance was investigated.The results showed that the catalytic activities of quenched β-MnO2 nanorods were significantly better than that of precursor and naturally cooled β-MnO2 nanorods after calcination. Notably, the β-MnO2 nanorods calcined at 350 ℃ followed by rapid cooling achieved the highest catalytic performance, with a cinnamyl alcohol conversion of 53.1% and a cinnamaldehyde selectivity of 95.2%, outperforming several commercial non-noble metal oxides. Various physicochemical characterizations demonstrated that the quenching technique could enhance the surface lattice oxygen activity and oxidation ability of β-MnO2 nanorods, thereby effectively boosting their catalytic oxidation performance. This work demonstrates that quenching technique has a positive effect on increasing the surface oxygen vacancy concentration and catalytic performance of MnO2, which offers an effective strategy for designing the high-efficiency non-noble metal oxide catalysts.

       

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