No abstract

Benzene hydrogenation is an important industrial process. The reaction is incomplete, resulting in a mixture of benzene, cyclohexane, and/or cyclohexene that have to be separated before any further reactions. The currently used extractive and azeotropic distillations are operationally complex and energy intensive. Adsorptive separation provides an alternative energy-efficient method. However, the separation of the ternary mixture by adsorptive separation has not yet been reported. In the present research, we report two macrocyclic hosts with hydrogen-bonding sites in their cavities that are able to separate the ternary mixture of benzene, cyclohexene, and cyclohexane. NÀH•••p interactions were found to play a key role in the selective separation. In addition, fast adsorption, high loading ratios, and easy recycling are achieved with the present system, which is promising for practical applications.

Gravimetric density vs. adsorption energies of existing 2D materials and adsorbed H2 molecules as a function of pressure and temperature on Li doped C2N.

Phosphorene is receiving great research interests because of its peculiar physical properties. Nonetheless, no systematic studies on the transport properties modified due to defects have been performed. Here, we present the electronic band structure, defect formation energy and bias dependent transport property of various defective systems. We found that the defect formation energy is much less than that in graphene. The defect configuration strongly affects the electronic structure. The band gap vanishes in single vacancy layers, but the band gap reappears in divacancy layers. Interestingly, a single vacancy defect behaves like a p-type impurity for transport property. Unlike the common belief, we observe that the vacancy defect can contribute to greatly increasing the current. Along the zigzag direction, the current in the most stable single vacancy structure was significantly increased as compared with that found in the pristine layer. In addition, the current along the armchair direction was always greater than along the zigzag direction and we observed a strong anisotropic current ratio of armchair to zigzag direction.

Achieving and controlling valley splitting is a core issue for valleytronics applications. Conventionally, valley splitting was achieved by applying an external magnetic field or structural manipulation. However, this approach is less efficient. Here, we explored single layer and bilayer graphene on CrI 3 (g-CrI 3 and 2g-CrI 3 ) heterostructures to induce valley splitting. In g-CrI 3 , we found a valley splitting with the majority gap difference of Δ 1↑ − Δ 2↑ = 44 meV. Even in 2g-CrI 3 system, we also found valley splitting of Δ 1↑ − Δ 2↑ = 21 meV. Moreover, we also investigated the electric field effect on valley splitting. In both systems, we observed that valley splitting could be switched in the majority spin band. For instance, the sign of gap difference at ±K changed from Δ 1↑ > Δ 2↑ at zero field to Δ 1↑ < Δ 2↑ at a small applied electric field of 0.1 V/Å . With further increase of the electric field to 0.2 V/Å, valley splitting disappeared. Thus, we propose that a large value of valley splitting can be achieved and the sign of splitting can also be switched with electric field instead of magnetic field. This feature may be beneficial for designing of valleytronic based information process devices.npj 2D Materials and Applications (2019) 3:3 ; https://doi.