Titanium carbide-based nanocomposite: A promising reinforcing material for enzymatic CO₂ conversion

Enzymatic conversion of CO₂ to formate is a highly significant pathway for CO₂ utilization, but current level of conversion efficiency remains unsatisfactory due to low solubility of CO₂ under mild conditions. CO₂-philic materials can significantly augment the reaction by raising local concentration of substrate. Herein, the intercalated Ti₃C₂T_x, nano-silica (SiO₂) and carbon nitride (CN) with abundant CO₂ adsorption sites were introduced to fabricate Ti₃C₂T_x based nanocomposites, Ti₃C₂T_x/SiO₂/CN (TSCN), for the first time. As the controls, binary composites including Ti₃C₂T_x/SiO₂ (TS), Ti₃C₂T_x/CN (TCN) and SiO₂/CN (SCN) were also studied. For each kind of material, the composition, structure, morphology, and application performance in the enzymatic CO₂ conversion were characterized and influencing factors were investigated. Among these composites, TSCN exhibited the best application performance and the enzyme reaction was accelerated up to 23.9 times that of the blank system. The value could reach as high as 35.3 after polyethyleneimine (PEI) modification. Following that, PEI modified composites were used as carrier of formate dehydrogenase (FDH) and apparent specific activity was up to 2.8 times that of free enzyme, which could retain 88.2% of the initial value after 10 cycles associated with the structural integrity. This work provides new impetus to CO₂ capture and conversion in a clean and mild way that shows bright application prospects.