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Manipulation of the oxidation states of the metal species within metal−organic frameworks leads to compositional, structural, and surface property evolutions, which will impact their performance as sorbents in adsorptive separation processes. In this study, we propose a new low-cost postsynthesis strategy to modify the oxidation states of copper species within the copper-1,3,5-benzenetricarboxylic acid (Cu-BTC) structure employing Na 2 S 2 O 3 as the reducing agent. The compositional and structural evolutions of the modified samples were thoroughly characterized by a series of methods, and the dimethyl disulfide (DMDS) adsorption performance was evaluated. Accurately controlled reduction of Cu(II) to Cu(I) and formation of nanopores in the modified Cu(I)/Cu(II)-BTC samples have been observed and confirmed experimentally. Specifically, the sample 0.46/Cu-BTC/24h with a Cu(I)/Cu(II) molar ratio of 1.79 exhibits both the highest DMDS adsorption capacity (146.66 mg-S/g) and fastest diffusion with D of 7.59 × 10 −13 cm 2 /s at 298 K. Further density functional theory calculations reveal that the modified Cu(I)/Cu(II)-BTC structures exhibit much higher interaction energy, E in , with DMDS (70.65 kJ/mol) than the parent Cu(II)-BTC (20.28 kJ/mol). Controllable reduction of Cu(II) to Cu(I) in Cu-BTC leads to significantly enhanced guest−host interactions as well as the formation of uniform nanoscale porosity leading to effect enhancement for the adsorption of DMDS using modified Cu-BTC materials.

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Abatement of emissions of greenhouse gases such as methane and carbon dioxide is crucial to reduce global warming. For that, dry reforming of methane allows to convert methane and carbon dioxide into useful synthesis gas, named 'syngas', a gas mixture rich in hydrogen and carbon monoxide. However, this process requires high temperatures of about 900 °C to activate methane and carbon dioxide because dry reforming of methane reaction is highly endothermic. Therefore, a solid catalyst with appropriate thermal properties is needed for the reaction. As a consequence, efficient heating of the reactor is required to control heat transfer and optimize energy consumption. Microwave-assisted dry reforming of methane thus appears as a promising alternative to conventional heating. Here we review the recent research on microwave-assisted dry reforming of methane. We present thermodynamical aspects of the dry reforming of methane, and basics of microwave heating and apparatus. We analyse reformers that use microwave heating. Catalysts used in a microwave-assisted reformer are presented and compared with reactors using conventional heating. Finally, the energy balance is discussed.

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