A short review of nanographenes: structures, properties and applications

Potential sensing of toxic chemical warfare agents (CWAs) by twisted nanographenes: A first principle approach

The toxic chemical warfare agents (CWAs) are extremely harmful to the living organisms. Their efficient detection and removal in a limited time span are essential for the human health and environmental security. Twisted nanographenes have great applications in the fields of energy storage and optoelectronics, but their use as sensors is rarely described. Therefore, we have explored the sensitivity and selectivity of twisted nanographene analogues (C₃₂H₁₆, C₆₄H₃₂) towards selected toxic CWAs, including phosgene, thiophosgene and formaldehyde. The interaction between CWAs and twisted nanographenes is mainly interpreted by considering the optimized geometries, adsorption energies, natural bond orbital (NBO), frontier molecular orbital (FMO), non-covalent interaction (NCI) and quantum theory of atoms in molecules (QTAIM) analyses. The structural geometries show that the central octagon of twisted nanographenes is the most favorable site of interaction. The interaction energies reveal the physisorption of selected CWAs on tNGs surface. The average energy gap change (%E_H-L^a) and % sensitivity are quantitatively determined to evaluate the sensing capability of the twisted nanographenes. Among the selected CWAs molecules, the sensitivity of tNG analogues (C₃₂H₁₆ and C₆₄H₃₂) is superior towards thiophosgene (ThP), which is revealed by the high interaction energies of -8.19 and - 12.17 kcal/mol, respectively. This theoretical study will help experimentalists to devise novel sensors based on twisted nanographenes for the detection of toxic CWAs which may also work efficiently under the humid conditions.

Acenaphthenoannulation Induced by the Dual Lewis Acidity of Alumina

We have discovered a dual (i. e., soft and hard) Lewis acidity of alumina that enables rapid one‐pot π‐extension through the activation of terminal alkynes followed by C−F activation. The tandem reaction introduces an acenaphthene fragment – an essential moiety of geodesic polyarenes. This reaction provides quick access to elusive non‐alternant polyarenes such as π‐extended buckybowls and helicenes through three‐point annulation of the 1‐(2‐ethynyl‐6‐fluorophenyl)naphthalene moiety. The versatility of the developed method was demonstrated by the synthesis of unprecedented structural fragments of elusive geodesic graphene nanoribbons.

Photophysics of nanographenes: from polycyclic aromatic hydrocarbons to graphene nanoribbons

Graphene quantum dots (GQDs) and nanoribbons (GNRs) are classes of nanographene molecules that exhibit highly tunable photophysical properties. There have been great strides in recent years to advance our understanding of nanographene photophysics and develop their use in light-harvesting systems, such as artificial photosynthesis. Here, we review the latest studies of GQDs and GNRs which have shed new light onto their photophysical underpinnings through computational and advanced spectroscopic techniques. We discuss how the size, symmetry, and shape of nanographenes influence their molecular orbital structures and, consequentially, their spectroscopic signatures. The scope of this review is to comprehensively lay out the general photophysics of nanographenes starting with benzene and building up to larger polycyclic aromatic hydrocarbons, GQDs, and GNRs. We also explore a collection of publications from recent years that build upon the current understanding of nanographene photophysics and their potential application in light-driven processes from display, lasing, and sensing technology to photocatalytic water splitting.

Application of Graphene Hybrid Materials in Fault Characteristic Gas Detection of Oil-Immersed Equipment

Graphene and its hybrid materials, due to their unique structures and properties, have attracted enormous attention for both fundamental and applied research in the gas sensing field. This review highlights the recent advances in the application of graphene-based gas sensors in fault characteristic gas detection of oil-immersed equipment, which can effectively achieve condition monitoring of the oil-immersed power equipment. In this review, the synthetic methods of graphene hybrid materials with noble metals, metal oxides and their combination are presented. Then, the basic sensing mechanisms of graphene hybrid materials and gas sensing properties of graphene hybrid materials sensors to hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), acetylene (C2H2), ethylene (C2H4), and ethane (C2H6), which are the fault characteristic gas in oil-immersed power equipment, are summarized. Finally, the future challenges and prospects of graphene hybrid materials gas sensors in this field are discussed.