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• A photoelectrochemical electrode was fabricated based on a graphene honeycomb film. • A fluorescent probe (AFP-PFBT-GOD) was synthesized for the detection current promotion. • This photoelectrochemical biosensor can sensitively detect alpha-fetoprotein by competitive immunoassay. • The photoelectrochemical biosensor has high detection sensitivity and good reliability. • The detection limit of alpha-fetoprotein is lower than 0.05 ng/mL. Alpha-fetoprotein (AFP) in adult serum often appears in early liver cancer. Therefore, early detection of an abnormal elevation of AFP concentration is important for the early diagnosis and treatment of primary liver cancer. In this work, a photoelectrochemical (PEC) electrode was fabricated for AFP-sensitive detection based on a reduced graphene oxide (rGO) honeycomb structure. After layer-by-layer bioconjugation, the immunoassay graphene electrode was modified with anti-AFP antibodies (Ab). Meanwhile, polymer nanoparticles (PFBT dots) were prepared via a nanoprecipitation method. In addition, the AFP was modified by using the PFBT dots and glucose oxidase (GOD), which formed a fluorescent probe (AFP-PFBT-GOD). By the competitive linkage of AFP and AFP-PFBT-GOD onto the anti-AFP modified honeycomb structure electrode, an immunosensor for AFP detection was obtained. During the PEC test, the electrons produced by the catalytic reaction of glucose and GOD can scavenge the photogenerated holes on the PFBT dots, which can reduce the recombination of photogenerated holes and electrons on the PFBT dots. The PEC immunosensor based on a rGO honeycomb structure exhibited a linear detection range of 0.05–100 ng/mL with a detection limit of 0.05 ng/mL. The excellent detection performance of the graphene PEC biosensor provides an opportunity for the early diagnosis of primary liver cancer. [ABSTRACT FROM AUTHOR]

Abstract Photonic graphene, a photonic crystal with honeycomb structures, has been intensively studied in both theoretical and applied fields. Similar to graphene which admits Dirac Fermions and topological edge states, photonic graphene supports novel and subtle propagating modes (edge modes) of electromagnetic waves. These modes have wide applications in many optical systems. In this paper, we propose a novel gradient recovery method based on Bloch theory for the computation of topological edge modes in photonic graphene. Compared to standard finite element methods, this method provides higher order accuracy with the help of gradient recovery technique. This high order accuracy is desired for constructing the propagating electromagnetic modes in applications. We analyze the accuracy and prove the superconvergence of this method. Numerical examples are presented to show the efficiency by computing the edge mode for the P -symmetry and C -symmetry breaking cases in honeycomb structures. [ABSTRACT FROM AUTHOR]

A bio-inspired graphene/Au@ ZnO photoelectrode has been prepared via breath figure method, in which Au@ ZnO nanospheres were uniformly distributed in the whole honeycomb film. The size of the honeycomb holes effects the light using efficiency. The honeycomb film with smaller holes in more ordered array shows better antireflective property. All the formed graphene/Au@ ZnO honeycomb photoelectrodes show a fast, stable, and reversible response of photocurrent accompanied by each switch-on and switch-off event. Au@ ZnO-modified graphene honeycomb film can combine the advantages of increased light harvesting provided by honeycomb structure, efficient charge separation from Au nanoparticles ( NPs), and efficient electron transfer provided by graphene. Au@ ZnO- modified graphene honeycomb film shows a two-fold increase of photocurrent generation than ZnO-modified graphene honeycomb film and a three-fold increase of photocurrent generation than Au@ ZnO-modified graphene smooth film, respectively. The rational design and engineering of multi components with different functions in a hybrid bio-inspired structure hold great promise for further efficient solar energy conversion devices. [ABSTRACT FROM AUTHOR]

Honeycomb 3D graphene-like Co 9 S 8 nanocrystallines were successfully synthesized using cobalt and Na 2 S·9H 2 O as starting materials without a template via a simple hydrothermal route. The composition, structure, morphology, and catalytic activity of the as-prepared Co 9 S 8 were characterized by investigation of XRD, SEM, EDS, XPS, GC–MS and HPLC. It was found that an appropriate concentration of inexpensive NaHCO 3 play a critical role for the formation of honeycomb Co 9 S 8 nanocrystallines. On the other hand, Co 9 S 8 acted as a catalyst in the hydrothermal reaction, producing formic acid reduced from NaHCO 3 as high as 3680 mg/L. It indicates that the present study not only proposes a simple way of honeycomb Co 9 S 8 synthesis, but also provides a potential approach to CO 2 reduction. [ABSTRACT FROM AUTHOR]

We demonstrated a facile approach for synthesizing three-dimensional (3D), honeycomb-structured graphene scaffold in the solid flame of a (0.5+ k ) Zn+ k CuO+(CH 2 -CHCl)n reaction system. FESEM-based analyses of the acid purified porous graphene samples revealed that the synthesized graphene had a 3D, honeycomb-like structure with cell sizes of 20–100 nm and wall thicknesses of 1–3 nm. The specific surface area of the graphene sample prepared in the solid flame was about ~1043 m 2 /g). [ABSTRACT FROM AUTHOR]

Simple monatomic amorphous 2D models with Honeycomb structure are obtained from 2D simple monatomic liquids with Honeycomb interaction potential (Rechtsman et al., Phys. Rev. Lett. 95, 228301 (2005)) via molecular dynamics (MD) simulations. Models are observed by cooling from the melt at various cooling rates. Temperature dependence of thermodynamic and structural properties including total energy, mean ring size, mean coordination number is studied in order to show evolution of structure and thermodynamics upon cooling from the melt. Structural properties of the amorphous Honeycomb structures are studied via radial distribution function (RDF), coordination number and ring distributions together with 2D visualization of the atomic configurations. Amorphous Honeycomb structures contain a large amount of structural defects including new ones which have not been previously reported yet. Cooling rate dependence of structural properties of the obtained amorphous Honeycomb structures is analyzed. Although amorphous graphene has been proposed theoretically and/or recently obtained by the experiments, our understanding of structural properties of the system is still poor. Therefore, our simulations highlight the situation and give deeper understanding of structure and thermodynamics of the glassy state of this novel 2D material. [ABSTRACT FROM AUTHOR]

[Display omitted] • The synthesis of Ni-Co LDH/G composite was largely optimized by microwave method. • Honeycomb structure guarantee its excellent electrochemical property. • Orbitals hybridization effect of composite contribute to the enhanced rate property. Nickel cobalt layered double hydroxide (Ni-Co LDH) is an exciting new electrode material because of its high theoretical capacity and redox activity. However, the complicated synthesis process and the intrinsically low conductivity impede its large-scale commercial application. Hence, a high-efficiency microwave liquid synthesis method was employed to rapidly prepare honeycomb-structured Ni-Co LDH nanosheets on graphene (Ni-Co LDH/G) composite, within minutes range of synthesis time. By introducing graphene, the poor intrinsic conductivity of the Ni-Co LDH could be ameliorated by hybridization effect, as reveled by density functional theory calculations, thus enhancing the rate capability greatly: Ni-Co LDH/G composite retained 87.1% of capacity at high rate, whereas only 50.5% was retained for Ni-Co LDH. In addition, the hybrid supercapacitor with Ni-Co LDH/G//activated carbon could deliver a high energy density of 40.6 Wh kg−1 at 400 W kg−1, along with a stable cycling lifespan with 83.2% of capacity retention after 10,200 cycles. These encouraging findings highlight that microwave synthesis could be an efficient route to engineer coordinating Ni-Co LDH/G composite for advanced electrode materials in supercapacitors. [ABSTRACT FROM AUTHOR]

A useful Li: A simple reaction between Li2O and CO, gives a new type of three‐dimensional graphene sheets—honeycomb‐structured graphene. A dye‐sensitized solar cell (DSSC) with the new graphene counter electrode has an energy conversion efficiency as high as 7.8 %, which is comparable to that of DSSCs with an expensive Pt counter electrode. [ABSTRACT FROM AUTHOR]

Porous graphene‐based composites offer immense potential for microwave absorption because of their light weight and high performance. In this work, a honeycomb structure filled with porous graphene is demonstrated with excellent radar‐absorbing properties. This graphene‐based composite reaches the maximum reflection loss (RL) of −15 dB at 8.8 GHz with only a thickness of 4.0 mm and an areal density of 0.26 kg m−2. Raman spectroscopy confirms the existence of graphene and scanning electron microscopy images reveal how these large graphene flakes are arranged to a three‐dimensional porous structure. In addition, a monolithic porous graphene aerogel, without the honeycomb core, and a RL simulation of it are also investigated for comparison, which reveals antipodal properties. This work shows that the insulated honeycomb structure increases the surface characteristic impedance of the whole composite material, which mainly contributes to the reduction of total reflection from the interface. Various structural influence factors have been analyzed, the results provide a new idea for exploring high‐performance microwave absorbers of graphene‐based materials. [ABSTRACT FROM AUTHOR]