Synthesis of zeolitic imidazolate framework-8 and gold nanoparticles in a sustained out-of-equilibrium state

The design and synthesis of crystalline materials are challenging due to the proper control over the size and polydispersity of the samples, which determine their physical and chemical properties and thus applicability. Metal-organic frameworks (MOFs) are promising materials in many applications due to their unique structure. MOFs have been predominantly synthesized by bulk methods, where the concentration of the reagents gradually decreased, which affected the further nucleation and crystal growth. Here we show an out-of-equilibrium method for the generation of zeolitic imidazolate framework-8 (ZIF-8) crystals, where the non-equilibrium crystal growth is maintained by a continuous two-side feed of the reagents in a hydrogel matrix. The size and the polydispersity of the crystals are controlled by the fixed and antagonistic constant mass fluxes of the reagents and by the reaction time. We also present that our approach can be extended to synthesize gold nanoparticles in a redox process.

Automated summary

The design and synthesis of crystalline materials require proper control over size and polydispersity. In this study, an out-of-equilibrium method using a continuous two-side feed of reagents in a hydrogel matrix was utilized to generate ZIF-8 crystals. The size and polydispersity of the crystals were controlled by mass fluxes of reagents and reaction time. This approach was also shown to be applicable for synthesizing gold nanoparticles in a redox process.