Crystallinity-Enhanced CO2 Adsorption by Sodium Poly(Heptazine Imide) Frameworks

resumo

This work presents sodium poly(heptazine imide) (NaPHI)-based materials, synthesized in a NaCl medium, as highly effective platforms for CO2 capture. High crystallinity-an often-overlooked aspect in PHI frameworks-is identified as a key factor governing CO2 adsorption capacity in microporous structures. Thermogravimetric analysis and manometric studies reveal a CO2 uptake of approximate to 3.8 mmol g-1, at 1 bar and 25 degrees C, surpassing most reported PHI-based adsorbents under similar conditions. Exchanging Na+ with K+ or Rb+ preserves CO2 adsorption performance, whereas Cs+ incorporation induces structural distortion, greatly reducing CO2 adsorption capacity in PHI. These materials exhibit excellent cyclic stability (20 cycles) without degradation and CO2 adsorption capacity loss. Notably, at flue gas-relevant temperature (100 degrees C), NaPHI attains a CO2 capacity of 2.1 mmol g-1, doubling the performance of benchmark Zeolite 13X (1.1 mmol g-1). Ideal Adsorbed Solution Theory confirms remarkable CO2/N2 selectivity (approximate to 3.8 mmol g-1 vs typical N2 adsorption of 0.3 mmol g-1), a critical property for postcombustion CO2 capture. These findings position PHI-based materials as a disruptive platform for CO2 adsorption, offering 1) straightforward synthesis from readily available precursors, 2) promising scalability, and 3) outstanding performance.

palavras-chave

ACTIVATED CARBONS; CAPTURE; SELECTIVITY; ZEOLITES; HYDROGEN; BIOCHAR

categoria

Chemistry; Science & Technology - Other Topics

autores

Ouro, P; Cuevas, A; Liessem, J; Mitoraj, D; Beranek, R; Díaz, E; Ordóñez, S; Marin-Montesinos, I; Pereira, D; Sardo, M; Krivtsov, I; Mafra, L; Ilkaeva, M

Grupos

G1 - Materiais Porosos e Nanossistemas

Projectos

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

Rede Nacional de Ressonância Magnética Nuclear (PTNMR)

Unveiling CO2 chemisorption mechanisms in solid adsorbents via surface-enhanced ex(in)-situ NMR (NMR4CO2)

agradecimentos

The authors acknowledge Spanish Ministry of Science, Innovation and Universities, State Research Agency and the FEDER (Projects PID2023-148187OB-I00 and PID2020-113558RB-C41) for financing this work. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020), UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020), financed by national funds through the FCT/MCTES (PIDDAC). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project 022161 (cofinanced by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC). This work has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program under Grant Agreements 865974 and 101122061 (SUNGATE) and from the Deutsche Forschungsgemeinschaft, DFG (German Research Foundation) via the TRR 234 CataLight-Projektnummer 364549901 [B6]. MI also acknowledges the Spanish Ministry of Science, Innovation, and Universities for the "Beatriz Galindo" Scholarship (MU-23-BG22/00145).