RESUMEN
Three-dimensionally (3D) well-ordered and highly integrated graphene hybrid architectures are considered to be next-generation multifunctional graphene materials but still remain elusive. Here, we report the first realization of unprecedented 3D-patterned graphene nano-ensembles composed of a graphene monolayer, a tailor-made structured organophenyl layer, and three metal oxide films, providing the first example of such a hybrid nano-architecture. These spatially resolved and hierarchically structured quinary hybrids are generated via a two-dimensional (2D)-functionalization-mediated atomic layer deposition growth process, involving an initial lateral molecular programming of the graphene lattice via lithography-assisted 2D functionalization and a subsequent stepwise molecular assembly in these regions in the z-direction. Our breakthrough lays the foundation for the construction of emerging 3D-patterned graphene heterostructures.
RESUMEN
Photonic circuit systems based on optical waveguiding heteroarchitectures have attracted considerable interest owing to their potential to overcome the speed limitation in electronic circuits by modulating the optical signal at the micro- or nanoscale. However, controlling the parameters, including the wavelength and polarization of the light outcoupling, as well as the sequence among different building blocks, remains a key issue. Herein, supramolecular heteroarchitectures made by phosphorescent organometallic complexes of Pt, Pd, Cu, and Au are applied as photonic logic gates that show continuously variable emission colors from 475 to 810 nm, low waveguide losses down to 0.0077 dB µm-1 , and remarkable excitation-light polarization-dependent photoluminescence with anisotropy ratios up to 0.68. The sequences among Pt, Pd, Au, and Cu building blocks in the heteroarchitectures are controlled by living supramolecular polymerization or crystallization-driven self-assembly synthetic approaches. The results indicate the prospects for using organometallic complexes and supramolecular synthetic approaches to prepare photonic circuit systems with tunable emission color and controllable sequences among different blocks that achieve modulation of the optical signal in the visible-to-near-infrared spectral region.
RESUMEN
The development of highly efficient non-precious metal electrocatalysts for the oxygen evolution reaction (OER) in low-grade or saline water is currently of great importance for the large-scale production of hydrogen. In this study, by using an electrochemical activation pretreatment, metal oxy(hydroxide) nanosheet structures derived from self-supported nickel-iron phosphide and nitride nanoarrays grown on Ni foam are successfully fabricated for OER catalysis in saline water. It is demonstrated that the different NiOOH and NiOOH@FeOOH (NiOOH grown on FeOOH) structures are generated from nickel-iron nitride and phosphide, respectively, after electrochemical activation. In particular, the NiOOH@FeOOH heteroarchitecture shows outstanding electrocatalytic performance with an ultralow overpotential of 292 mV to drive the current density of 500 mA cm-2 . An unconventional dual-sites mechanism (UDSM) is proposed to address the OER process on NiOOH@FeOOH and show that the FeOOH underlayer plays a critical role regarding the enhanced OER activity of NiOOH. The new possible UDSM involving two reaction sites presents a different understanding of the OER process on multi-OH layer complexes, which is expected to guide the design of heteroarchitecture electrocatalysts.
RESUMEN
The sequential vertical polyfunctionalization of 2D addend-patterned graphene is still elusive. Here, we report a practical realization of this goal via a "molecular building blocks" approach, which is based on a combination of a lithography-assisted reductive functionalization approach and a post-functionalization step to sequentially and controllably link the molecular building blocks ethylpyridine, cis-dichlorobis(2,2'-bipyridyl)ruthenium, and triphenylphosphine (4-methylbenzenethiol, respectively) on selected lattice regions of a graphene matrix. The assembled 2D hetero-architectures are unambiguously characterized by various spectroscopic and microscopic measurements, revealing the stepwise stacking of the molecular building blocks on the graphene surface. Our method overcomes the current limitation of a one-layer-only binding to the graphene surface and opens the door for a vertical growth in the z-direction.
RESUMEN
Advanced two-dimensional nanosheets that promote the dynamic transportation and storage capacity of ions are significant for high-performance electrochemical capacitors (ECs). However, such materials often possess a low energy density. We have developed an ordered heteroarchitecture of molybdenum disulfide-carbon nanotubes (MoS2 -CNTs) in which CNTs are vertically grafted within a MoS2 framework by C-Mo covalent bonds. Benefiting from this inâ situ vertical bridge, high-speed interlaminar conductivity, unimpeded ion-diffusion channels and sufficient pseudocapacitive reactivity, the MoS2 -CNTs presents ultralarge capacitance (5485â F g-1 ) and good structural stability in potassium hydroxide electrolyte. Moreover, the all-unified solid-state flexible ECs obtained through direct-write printing construction deliver high energy density (226â mWh g-1 ), good capacitance (723â F g-1 ) and stable high/low-temperature operating ability, which can power a wearable health-monitoring device.
