Chemical reaction kinetics-guided size and pore structure tuning strategy for fabricating hollow carbon spheres and their selective adsorption properties

Hollow carbon spheres (HCSs) with flexible morphology configuration and pore structure have always been expected owing to their promising broad applications. In this work, chemical reaction kinetics guided strategy was proposed to tailor the size and pore structure of HCSs based on the modified stöber method. By varying the reaction temperature and the moment of adding carbon precursors to the solution of tetrapropyl orthosilicate (TPOS), the particle size, cavity diameter, shell thickness and pore size could be tuned conveniently. By altering the reaction temperature from 6 to 45 °C or varying the time-lag of adding carbon precursors from 0 to 180 min, the size, shell thickness and pore size of HCSs could be successfully tailored in the range of 199–697 nm, 10–104 nm and 4.35–18.87 nm, respectively. Moreover, the resulting HCSs not only exhibited excellent adsorption for Vitamin B₁₂ (VB₁₂), methylene blue (MB) and Cr(Ⅵ), but also featured with selective adsorption for different-sized adsorbates. This demonstrates that the chemical reaction kinetics guided pore structure tuning strategy could be an effective way to develop adsorbents with specific pore structure.