Ti3C2Tx intercalation, modification and application in enzymatic CO2 conversion

Ti3C2Txas a typical MXene material has a multilayer structure similar to accordion, whose interlayer spacing and specific surface area can be regulated by intercalation and modification. In this work, the effects of several kinds of cation-containing intercalators including NH4OH, KOH and NH4OH/KCl on the structure of Ti3C2Tx and its application performance in enzymatic CO2 conversion were investigated for the first time. The results show that Ti3C2Tx intercalated with NH4OH/KCl had larger layer spacing (25.25 angstrom) and specific surface area (20.85 m2/g), and better enhancing effect. The initial reaction rate was 0.379 mM/h, which was separately 1.04, 1.42, 1.76 and 5.29 times that of Ti3C2Tx/KOH, Ti3C2Tx/NH4OH, Ti3C2Tx and the blank system. Following that, Ti3C2Tx/NH4OH/ KCl was modified by polyethyleneimine (PEI) and dopamine (DA) and the concentration of modifier was optimized. PEI modified Ti3C2Tx/NH4OH/KCl (PEI-Ti3C2Tx) was superior to PEI/DA modified that in the N content, CO2 adsorption capacity and application performance. With the addition of 20 mg PEI-Ti3C2Tx, the initial reaction rate was 0.658 mM/h, which was 1.74 and 9.2 times that of before modification and the blank system, respectively. PEI-Ti3C2Tx also exhibited a good reusability and the initial reaction rate was 89.4% of the initial value after 10 cycles.