Selective Capturing of the CO₂ Emissions Utilizing Ecological (3-Mercaptopropyl)trimethoxysilane-Coated Porous Organic Polymers in Composite Materials

Capturing carbon dioxide (CO₂) is still a major obstacle in the fight against climate change and the reduction of greenhouse gas emissions. To address this problem, we employed a simple Friedel–Crafts alkylation to investigate the effectiveness of porous organic polymers (POPs) based on triphenylamine (TPA) and trihydroxy aryl terms derived from chloranil (CH), designated as TPA-CH POP. We then treated the TPA-CH POP with (3-mercaptopropyl)trimethoxysilane (3-MPTS), forming a TPA-CH POP-SH nanocomposite to enhance CO₂ capture. Utilizing FTIR, solid-state NMR, SEM, TEM, along with XPS techniques, the molecular makeup, morphological characteristics, as well as physical features of TPA-CH POP and the TPA-CH POP-SH nanocomposite were thoroughly explored. Upon scorching to 800 °C, the TPA-CH POP-SH nanocomposite demonstrated more thermal durability over TPA-CH POP, achieving a char yield of up to 71.5 wt.%. The TPA-CH POP-SH nanocomposite displayed a 2.5-times better CO₂ capture, as well as a comparable adsorption capacity of 48.07 cm³ g⁻¹ at 273 K. Additionally, we found that the TPA-CH POP-SH nanocomposite exhibited an improved CO₂/nitrogen (N₂) selectivity versus the original TPA-CH POP. Typical enthalpy changes for CO₂ capture were somewhat increased by the 3-MPTS coating, indicating greater binding energies between CO₂ molecules and the adsorbent surface. Our outcomes demonstrate that a TPA-CH POP composite coated with MPTS is a viable candidate for effective CO₂ capture uses. Our findings encourage the investigation of different functional groups and optimization strategies.