چكيده به لاتين
In this study, titanium carbide MXene (Ti3C2Tx) synthesized by two different methods, along with Ti3C2Tx samples modified with KOH, were investigated for carbon dioxide (CO2) adsorption and sensing applications. Structural analyses using XRD, FTIR, BET, and SEM revealed that KOH modification of Ti3C2Tx increases active surface sites and alters the MXene’s layered structure (greater layer separation and formation of larger pores), enhancing CO2 adsorption and sensing capabilities. The adsorption capacity of the optimized Ti3C2Tx-KOH 20 sample reached 14.2 mmol/g under 9 bar pressure and 25°C, showing significant improvement compared to pristine Ti3C2Tx-LiF/HCl (11.61 mmol/g). For adsorption optimization, Response Surface Methodology (RSM) with a Central Composite Design was employed, showing that temperature, pressure, and KOH weight percentage are key factors influencing adsorption capacity. Under optimal conditions (25°C, 5.643 bar, and 20.946 wt% KOH), an adsorption capacity of 9.837 mmol/g was achieved. The Freundlich isotherm model best fit the experimental adsorption data, indicating that CO₂ adsorption on the optimized sample is a physical, multilayer process on a heterogeneous surface. Kinetic studies further showed that the fractional-order kinetic model provided the best fit, suggesting complex adsorption processes involving multiple reaction pathways. Thermodynamic analysis confirmed that the adsorption process is exothermic and spontaneous. In cyclic regeneration analysis, the optimized Ti3C2Tx-KOH 20 sample retained approximately 97.23% of its initial adsorption capacity after 10 adsorption-regeneration cycles, demonstrating high stability and reusability under various operational conditions. In sensing applications, the Ti3C2Tx-KOH 20-based sensor showed superior CO₂ detection performance compared to the Ti3C2Tx-LiF/HCl sensor. Specifically, the Ti3C2Tx-KOH 20 sensor exhibited a shorter response time (17 seconds) and faster recovery time (23 seconds) compared to the Ti3C2Tx-LiF/HCl sensor (response time of 21 seconds and recovery time of 38 seconds) at 10 vol% CO₂. Moreover, the sensitivities of the Ti3C2Tx-LiF/HCl and Ti3C2Tx-KOH 20 sensors to pure CO₂ were 31.109 and 48.627, respectively. Stability assessment over a 30-day period showed less than 3.92% reduction in response for the Ti3C2Tx-KOH 20 sensor, indicating reliable and stable long-term performance. This study demonstrates that the Ti3C2Tx-KOH 20 sample, due to its structural and functional optimizations, is an effective CO₂ adsorbent and sensor, holding significant potential for industrial and environmental applications.
