Tuning residual metal in partially etched carbide-derived carbons for enhanced acid gas adsorption

Abstract An in-depth study on post-synthetic modification of residual metal in carbide-derived carbons (CDCs) from an Al4C3 starting material has been performed. Ambient temperature high humidity studies reveal the conversion of residual parent nanoparticles to poly(aluminum chloride) (PAC). Alkaline modification was employed resulting in the formation of amorphous Al(OH)3 nanoparticles within 24h of reaction. After aging for up to 11 days, amorphous nanoparticles convert to well-crystallized α-Al(OH)3 (bayerite). Al4C3-CDCs with amorphous Al(OH)3 display significantly-enhanced interactions with SO2 and CO2 while X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared (ATR-IR) spectroscopy indicated no significant change in the surface chemistry of the carbon. SO2 breakthrough results at 1000 ppm SO2 exhibit uptakes near 2 mmol g−1, displaying viability for these adsorbents in flue gas remediation applications. The results of this work provide detailed modification strategies for tuning the extent and type of residual metal embedded in the final CDC structure, along with further insights into the ramifications of oxygen functionalities and pore size distribution of CDCs for SO2 adsorption.