Abstract Silver oxide nanoparticles doped manganese (IV) oxide along with varying percentages of highly reduced graphene oxide (HRG) [Ag2O(1%)–MnO2/(X%)HRG] nanocomposites were fabricated through a simple co-precipitation method followed by calcination at 400 °C. The as-prepared nanocomposite upon calcination at 300 °C and 500 °C temperatures, yields the manganese carbonate (MnCO3) and manganese (III) oxide (Mn2O3) composites i.e. Ag2O(1%)–MnCO3/(X%)HRG and Ag2O(1%)–Mn2O3/(X%)HRG, correspondingly. The structural composition of the prepared nanocomposites has confirmed by several characterization techniques. The nanocomposites have successfully utilized as a catalyst for liquid-phase oxidation of aromatic alcohols in presence of O2 as a green oxidant under alkali-free conditions. In addition, a comparative study was performed to assess the activity of the manganese carbonates and manganese oxides for aerial oxidation of benzyl alcohol into benzaldehyde as a model reaction. Effects of various parameters have thoroughly examined in detail and the Ag2O(1%)–MnO2/(5%)HRG catalyst exhibited the highest activity in the aerial oxidation of benzyl alcohol to benzaldehyde with a 100% conversion and >99% selectivity in a remarkably short reaction time (35 min) than the undoped precursor i.e. Ag2O(1%)–MnO2. The presence of HRG dopant greatly enhanced the catalytic performance of Ag2O–MnO2 nanocatalysts could be attributed to the presence of carbon vacancies and topological defects as well as oxygen carrying functionalities on the HRG surface and increase in the surface area. The as-prepared catalyst could be efficiently recycled and reused up to five times without a discernible drop in its catalytic performance and the product selectivity remained unchanged. The prepared catalyst i.e. Ag2O(1%)–MnO2/(5%)HRG was employed as oxidation catalyst for a series of various substituted benzylic and aliphatic alcohols into their respective aldehydes and yielded complete conversion with excellent product selectivity with no further oxidation to acids.

中文翻译：

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Ag 2 O 纳米颗粒/MnCO 3 、-MnO 2 或-Mn 2 O 3 固定在高度还原的氧化石墨烯复合材料上作为一种高效且可回收的氧化催化剂

摘要 氧化银纳米颗粒掺杂锰 (IV) 氧化物以及不同百分比的高度还原氧化石墨烯 (HRG) [Ag2O(1%)–MnO2/(X%)HRG] 纳米复合材料通过简单的共沉淀方法制备，然后煅烧在 400°C。所制备的纳米复合材料在 300 °C 和 500 °C 温度下煅烧，产生碳酸锰 (MnCO3) 和氧化锰 (Mn2O3) 复合材料，即 Ag2O(1%)–MnCO3/(X%)HRG 和 Ag2O (1%)–Mn2O3/(X%)HRG，相应地。制备的纳米复合材料的结构组成已通过多种表征技术得到证实。该纳米复合材料已成功用作在无碱条件下，在作为绿色氧化剂的 O2 存在下芳族醇液相氧化的催化剂。此外，进行了一项比较研究，以评估碳酸锰和氧化锰在将苯甲醇空气氧化成苯甲醛作为模型反应的活性。对各种参数的影响进行了彻底详细的研究，Ag2O(1%)-MnO2/(5%)HRG 催化剂在苯甲醇空气氧化成苯甲醛中表现出最高的活性，转化率为 100%，选择性大于 99%。反应时间（35 分钟）明显短于未掺杂的前体，即 Ag2O(1%)-MnO2。HRG掺杂剂的存在极大地提高了Ag2O-MnO2纳米催化剂的催化性能，这可能归因于HRG表面存在碳空位和拓扑缺陷以及载氧功能和表面积的增加。所制备的催化剂可以有效地回收和重复使用多达 5 次，而其催化性能没有明显下降，并且产物选择性保持不变。所制备的催化剂即 Ag2O(1%)–MnO2/(5%)HRG 用作一系列各种取代的苄醇和脂肪醇转化为各自醛的氧化催化剂，并以优异的产品选择性实现完全转化，无需进一步氧化成酸.