Convenient hydrothermal treatment combining with “Ship in Bottle” to construct Yolk-Shell N-Carbon@Ag-void@mSiO2 for high effective Nano-Catalysts

Abstract

More active sites will be exposed when noble metal particles are loaded on the core of yolk-shell nanospheres (NM-YSNS) to give higher metal utilization rate, catalytic activity, and good recycle stability. Herein, we adopt an efficient strategy to access the high-performance NM-YSNS via “ship in bottle” mindset on loading Ag nanoparticle on the core surface of core–shell structure accurately and the core shrinkage on forming yolk-shell structure. First, we systematically investigated the mechanism of SiO2 coating 3-aminophenol-co-formaldehyde nanoparticles to generate 3-aminophenol-co-formaldehyde@mesoporous SiO2 core–shell nanospheres (3-APF@mSiO2 CSNS). Interestingly, the core surface of 3-APF@mSiO2 CSNS became uneven after hydrothermal process, which provided positions for Ag, then additional Ag+ could reach the 3-APF surface through the mSiO2 shell and be in situ reduced into Ag particles by –NH- and –NH2 there. Similarly, the 3-APF@Au@mSiO2 CSNS were prepared successfully. After carbonizing 3-APF@Ag@mSiO2 CSNS, the N-Carbon@Ag-void@mSiO2 YSNS was obtained. The NM-YSNS catalyst had a high specific surface area of 258.8 m2g−1, mSiO2 shell of 3.8 nm mesoporous size, and core loaded with Ag particles firmly, showing a high turnover frequency of 137.08 h−1 and good recycle stability in catalytic reduction of 4-nitrophenol for preparing 4-aminophenol.