Structure Control Using Bioderived Solvents in Electrochemical Metal-Organic Framework Synthesis

Electrochemical synthesis of metal-organic frameworks (MOFs) has proven to possess many environmental advantages over traditional synthesis methods such as reduced energy use and shorter reaction times. However, the use of toxic, fossil fuel derived solvents such as N,N-dimethylformamide (DMF) presents a challenge to the environmental credentials of this method that has yet to be dealt with. Here, we investigate bioderived solvents, Cyrene (TM) and gamma-valerolactone (GVL), as an alternative for the synthesis of a range of MOFs via the anodic deposition method. The obtained MOF materials are characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to confirm their identities and morphologies and for comparison with MOFs synthesized using the traditional DMF-based solvent systems. When using Cyrene (TM) and GVL solvents, crystalline MOF materials were obtained of comparable quality to those afforded using DMF. However, in several cases, using Cyrene (TM) or GVL led to the formation of less stable, higher porosity MOF structures than those obtained using DMF, indicating that the larger bio solvent molecules may also play a templating role during the synthesis. This study successfully demonstrates the first-time electrochemical synthesis of MOFs has been performed using bio solvents and has highlighted that the use of bio solvents can provide a route to obtaining lower density, higher porosity MOF phases than those obtained using traditional solvents.

Automated summary

Electrochemical synthesis of metal-organic frameworks (MOFs) offers environmental advantages compared to traditional methods, but the use of toxic solvents like DMF poses challenges. This study investigates the use of bioderived solvents Cyrene(TM) and GVL as an alternative for MOF synthesis. Results show that Cyrene(TM) and GVL solvents can produce crystalline MOFs comparable to those obtained with DMF, but may also lead to less stable, higher porosity structures. This study demonstrates the first electrochemical synthesis of MOFs using bio solvents and highlights the potential for obtaining unique MOF phases.