## 2 Results and Discussion  
### Catalysts Characterization  
The functional groups of P-BVIMCI and BVIMCI were characterized by Fourier-transform infrared spectroscopy (FT-IR). As shown in Figure 1 and Figure S3, for P-BVIMCI, a peak at 1150 cm\({}^{-1}\) was attributed to C-N stretching vibrations in the imidazolium cation structure. A band at 1550 cm\({}^{-1}\) corresponded to imidazole ring vibrations. A characteristic absorption at 1440 cm\({}^{-1}\) was assigned to C-C stretching vibrations of aromatic rings, confirming the presence of imidazolium ionic moieties within the framework of poly(ionic liquid) [32]. Comparative analysis of BVIMCI and P-BVIMCI revealed critical polymerization evidence: The characteristic absorption peak of the C=C double bond located at 1650 cm\({}^{-1}\), as well as the vibrational peak of the unsaturated C-H on the vinyl group located at 970 cm\({}^{-1}\), showed a significant decrease in intensity compared to the peak at 1550 cm\({}^{-1}\) after the polymerization reaction. This change clearly confirms that the polymerization reaction was successfully carried out [33]. The microstructural morphology and elemental distribution of the P-BVIMCl catalyst were analyzed through SEM and EDS mapping, as shown in Figure 2. As shown in Figure 3a, P-BVIMCl consisted of primary particles stacked upon one another. These structural variations were attributed to modified polymerization parameters that induced changes in the polymer architecture [34]. Furthermore, the corresponding EDS mapping images of P-BVIMCl (Figure 2b-e) revealed uniform distributions of C, N, and Cl elements, demonstrating homogeneous dispersion of imidazole units within the framework of poly(ionic liquid)s.  
The chemical states of elements in P-BVIMCl were investigated using X-ray photoelectron spectroscopy (XPS), as shown in Figure 3. The XPS survey spectrum (Figure 3a) displayed characteristic peaks corresponding to C, N, and Cl elements. In the N 1s spectrum (Figure 3c), the peak at 401.44 eV was attributed to imidazolium nitrogen, while an additional peak observed at 399.18 eV likely originated from electron transfer caused by the strong interactions with surrounding charged ions [35]. The C 1s spectrum (Figure 3b) could be deconvoluted into two characteristic signals corresponding to C-C and C-N bonds,  
Figure 1: FT-IR spectra of P-BVIMCl and BVIMCl. Figure 2: SEM (**a**) of P-BVIMCl and EDS mapping (**b–e**) of P-BVIMCl. with binding energies at 284.80 eV and 286.32 eV, respectively [36]. The chlorine XPS spectrum (Figure 3d) exhibited two distinct peaks at 196.86 eV and 198.51 eV, which were assigned to the 2p3/2 and 2p1/2 orbitals of Cl\({}^{-}\) ions [37]. The presence of free chloride ions confirmed the successful occurrence of the quaternionic reaction. The pore structure and textural properties of P-BVIMCI were investigated by N\({}_{2}\) adsorption-desorption analysis (Figure 4a,b). The isotherm of P-BVIMCI exhibits a Type II profile with a distinct hysteresis loop at high relative pressures (p/p\({}_{0}\)), indicative of a uniform mesoporous structure. The average pore diameter was determined to be 3.72 nm, and the BET surface area was calculated as 6.0164 m\({}^{2}\cdot\)g\({}^{-1}\) (Table 1). Figure 4: (**a**) N\({}_{2}\) adsorption–desorption isotherms of P-BVIMCI (red: desorption isotherms; blue: adsorption isotherms); (**b**) pore size distribution profiles of P-BVIMCI; (**c**) CO\({}_{2}\) adsorption isotherms of P-BVIMCI; and (**d**) TG curves of P-BVIMCI and BVIMCI (red background: the weight loss interval). Figure 3: XPS survey and C 1s spectrum (**a,b**); N 1s and Cl 2p spectrum (**c,d**). Moreover, CO\({}_{2}\) adsorption performance tests revealed that P-BVIMCl achieved a CO\({}_{2}\) adsorption capacity of 1.853 cm\({}^{3}\cdot\)g\({}^{-1}\) under the specified conditions (Figure 4c). Additionally, thermal stability analysis of BVIMCl and P-BVIMCl catalysts was investigated by thermogravimetric (TG) characterization.