Solar-driven steam generation is an emerging, attractive, and sustainable technology for potential seawater desalination and wastewater purification. Despite the tremendous progress to date, some technological gaps still remain such as...

Molecular dynamics (MD) simulations using a reactive force field (ReaxFF) method for a Green River oil shale model demonstrate that the thermal decomposition of the oil shale molecule is initiated with the cleavage of the oxygen bridge (C–O bond), and the first product is formaldehyde (CH2O). The simulation results show that the C–O bond is weaker than the other bonds, agreeing with its smaller bond dissociation energy (BDE). The ring-opening position of the aliphatic ring is usually determined by the stability of free radicals formed in this process. For aromatic hydrocarbons, the long-chain substituents are found to be easier to leave and the cleavage of C–C bonds leads to a series of chain reactions and the formation of small fragments, such as ethylene and propylene. The bond cleavages are almost in accordance with the minimum bonding energy rule. NVT simulations show that the pyrolysis process progresses in two stages: the decomposition of kerogen into heavy (C40+) species and then the generation of light compounds. Recombinations and rearrangements of different fragments are also observed via MD simulations. The main hydrocarbon fragments of C10–C20 are regarded as the component or precursor of diesel oil. The formation pathways of typical aromatic components are analyzed by tracking the motion trajectories of relevant structures. The intermediates and products in MD simulations are found to be similar to the gas chromatography–mass spectrometry (GC–MS) results from previous experiments.

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The porous graphene film is ultrathin, lightweight and highly conductive, and exhibits excellent folding endurance and superior EMI shielding performance.

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Flexible poly­(vinyl alcohol)/reduced graphene oxide coated activated carbon (PVA/RGO@AC) composite films with extremely low graphene amounts were prepared by using AC as segregators and substrates. Decoration of AC with graphene to create an individual RGO-sheet-coated AC structure leads to a dramatic increase in the conductivity of AC and effectively prevents the restacking and agglomeration of graphene. The percolation threshold of the PVA/RGO@AC composites is as low as 0.17 wt % for RGO@AC, and, in particular, only 0.017 wt % RGO is needed. A high conductivity of 10.90 S/m and an impressive electromagnetic interference shielding effectiveness (EMI SE) of 25.6 dB with an absorption-dominated mechanism are achieved for PVA/RGO@AC composites with a low RGO loading of 1.0 wt %. The specific EMI SE of the composite reaches 17.5 dB/mm, outperforming most of the reported pioneering graphene-based polymer composites with such a low RGO amount. The excellent electrical property and outstanding EMI shielding performance are attributed to the internal well-constructed three-dimensional RGO–AC–RGO interconnected conductive network. Intriguingly, the fabricated composites exhibit a stable EMI SE even after 1000 bend–release cycles. These results demonstrate that our approach is a novel and promising method for producing highly conductive, high shielding performance, and cost-effective materials with very low graphene loading.