Investigation of MOF-derived humidity-proof hierarchical porous carbon frameworks as highly-selective toluene absorbents and sensing materials

Carbon frameworks (CFs) derived from metal-organic frameworks (MOFs) have been produced as adsorbents of toluene. To further obtain optimum hierarchical porous carbon structure of CFs, different treatment temperatures were applied to a typical kind of MOFs (ZIF-8). The adsorption capacity of the toluene of hierarchical porous CFs obtained from ZIF-8 under 1100 ?C (CF-1100, adsorption capacity of 208.5 mg/g) was higher than that of other carbonization temperature and MOFs. Impressively, the adsorbent CF-1100 also exhibited strong hydrophobicity, low desorption temperature, and good selectivity to toluene. The adsorption capacity decreased by only 10.4% under wet condition compared with the dry condition, standing on the top of the recently reported adsorbents. The impressive adsorption performance of CF-1100 is attributed to the larger specific surface area (1024 m2/g) and pore volume (0.497 cm3/g), newly generated micropores (pore width is 0.6?0.8 nm) and mesopores (pore width above 10 nm), and carbonaceous structure with higher degree of graphitization. Based on the adequate adsorption performance, CF-1100 coated quartz crystal microbalances as sensor also showed a high sensitivity of 0.4004 Hz/ppm and small relative standard deviations of 1.0745% for toluene sensing. This contribution provides a foundation for optimizing potential adsorbents and sensing materials for air pollution abatement.

Automated summary

Carbon frameworks derived from metal-organic frameworks have been produced as efficient adsorbents for toluene due to their optimal hierarchical porous structure. The CFs derived from ZIF-8 under 1100℃ exhibited the highest adsorption capacity, attributed to their larger specific surface area, newly generated micropores and mesopores, and higher degree of graphitization. These CFs also showed strong hydrophobicity, good selectivity to toluene, and high sensitivity when applied as sensors, providing potential for air pollution abatement.