Water vapor often present in the atmosphere will influence the adsorption of volatile organic compounds (VOCs). The competitive adsorption behavior of toluene and water vapor on synthesized zeolitic imidazolate framework-8 (ZIF-8) and graphene oxide (GO) hybrid composites was investigated in a humid atmosphere. The ZIF-8/GO composites were successfully prepared in a methanol system at room temperature and exhibited tunable nanoscale morphology and surface area, both determined by the GO content. A series of characterization techniques confirmed the formation of strong interactions between ZIF-8 and GO in the synthesized composites. Adsorption experiments demonstrated that the ZIF-8/GO composites with a GO content of 4 wt% had the highest toluene adsorption capacity of 116 mg g⁻¹ at a relative humidity (RH) of 55%, increased by 19% compared with pristine ZIF-8, and the recyclability of the adsorbent was investigated. The results showed that the synthesized ZIF-8/GO composites exhibited a higher toluene uptake capacity than pristine ZIF-8 crystals even at relatively high humidity, indicating that the ZIF-8/GO composites could be effective adsorbents in a humid atmosphere.

A copper-based metal–organic framework (MOF), also known as HKUST-1, was successfully synthesized, characterized, and evaluated for selective adsorption and separation of dichloromethane (DCM) and trichloromethane (TCM). The adsorption equilibria and kinetics of DCM and TCM were systematically investigated on the HKUST-1. Results showed that HKUST-1 has a high adsorption capacity for DCM (13.12 mmol g⁻¹) and TCM (8.53 mmol g⁻¹) at 298 K, respectively. From the kinetics results, the diffusion coefficients of DCM and TCM in HKUST-1 were estimated to be 3.73 × 10⁻⁹ cm² s⁻¹ and 0.44 × 10⁻⁹ cm² s⁻¹ at 318 K. In addition, their binary adsorption selectivity and diffusivity selectivity were predicted via the ideal adsorbed solution theory (IAST) method. The high adsorption selectivity (3.04) and diffusivity selectivity (8.93) at 318 K and 2.8 kPa indicated that HKUST-1 is a great candidate for selective adsorption and separation of DCM and TCM. Based on these results, the mechanism of adsorption and separation process has been discussed.

MOF functionalized with –NH ₂ exhibits improved adsorption capacity and selectivity for the adsorption and separation of dichloromethane and trichloromethane.

In this review, the research progress of MOF-based PC gas sensors from 1-D to 3-D PCs, which mainly include four aspects of sensing mechanism, material selection, structural optimization and sensing performances, is comprehensively summarized.

The properties of defects in organic-inorganic hybrid perovskite are widely studied from the first-principles calculation. However, the defects of methylamine (methylamine = CH₃NH₂), which would be easily formed during the preparation of the organic-inorganic hybrid perovskite, are rarely investigated. Thermodynamic properties as well as defect states of methylamine embedded MAPbX₃ (MA = methyl-ammonium = CH₃NH₃, X = Br, I) are studied based on first-principles calculations of density functional theory. It was found that there is a shallow defect level near the highest occupied molecular orbital, which induced by the interstitial methylamine defect in MAPbBr₃, will lead to an increase of photoluminescence. The calculation results showed that interstitial defect states of methylamine may move deeper due to the interaction between methylamine molecules and methyl-ammonium cations. It was also showed that the interstitial methylamine defect is stable at room temperature, and the defect can be removed easily by annealing.