Mesoporous silica-encapsulated gold core–shell nanoparticles for active solvent-free benzyl alcohol oxidation
Mesoporous silica-encapsulated gold core–shell nanoparticles for active solvent-free benzyl alcohol oxidation
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DOI：
10.1039/d0re00198h
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发表时间：
2020-09
影响因子：
3.9
通讯作者：
Ellis Hammond-Pereira;K. Bryant;T. Graham;Chen Yang;S. Mergelsberg;Di Wu;S. Saunders
中科院分区：
文献类型：
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作者：
Ellis Hammond-Pereira;K. Bryant;T. Graham;Chen Yang;S. Mergelsberg;Di Wu;S. Saunders
通过可调节的自下而上程序合成了二氧化硅封装的金核@壳纳米粒子（Au@SiO2 CSNP），以催化苯甲醇的有氧氧化。纳米颗粒具有介孔壳，可通过抑制较大物质的形成来提高选择性。向反应中添加碳酸钾可将转化率从 17.3% 提高至 60.4%，同时将选择性从 98.4% 降低至 75.0%。具有相似金表面积的金纳米粒子控制催化剂需要6倍的时间才能达到相同的转化率，仅实现49.4%的选择性。这些结果表明，尽管在碱性环境下，Au@SiO2 CSNPs 惰性二氧化硅壳内的孔径分布仍能抑制不需要的产物的形成，从而促进苯甲醛的选择性氧化。较小的活化能、传质分析和介孔分布共同表明，Au@SiO2 CSNP 催化剂通过有益的孔内取向表现出更高的活性，促进了较低的活化能机制途径。总而言之，这是一种有前途的催化结构，可以优化氧化化学，无需利用螯合剂或活性载体表面等表面相互作用因素。
Silica-encapsulated gold core@shell nanoparticles (Au@SiO2 CSNPs) were synthesized via a tunable bottom-up procedure to catalyze the aerobic oxidation of benzyl alcohol. The nanoparticles exhibit a mesoporous shell which enhances selectivity by inhibiting the formation of larger species. Adding potassium carbonate to the reaction increased conversion from 17.3 to 60.4% while decreasing selectivity from 98.4 to 75.0%. A gold nanoparticle control catalyst with a similar gold surface area took 6 times as long to reach the same conversion, achieving only 49.4% selectivity. These results suggest that the pore size distribution within the inert silica shell of Au@SiO2 CSNPs inhibits the formation of undesired products to facilitate the selective oxidation of benzaldehyde despite a basic environment. A smaller activation energy, mass transport analysis, and mesopore distribution together suggest the Au@SiO2 CSNP catalyst demonstrates higher activity through beneficial in-pore orientation, promoting a lower activation energy mechanistic pathway. Taken together, this is a promising catalytic structure to optimize oxidation chemistries, without leveraging surface-interacting factors like chelating agents or active support surfaces.