Graphdiyne (GDY) is a novel carbon allotrope that has attracted significant attention owing to its unique structural and electronic properties. Comprising sp²- and sp-hybridized carbon atoms, GDY forms a two-dimensional structure via conjugated −C≡C−C≡C− linkages. These linkages result in a highly π-conjugated system with a natural bandgap that distinguishes GDY from other carbon materials such as graphene. This review systematically provides an overview of GDY, with a focus on its intrinsic properties and synthesis strategies, techniques to characterize its structure, and recent advanced applications. First, we summarize several GDY synthesis strategies, providing a detailed discussion of the advantages and disadvantages associated with each approach. Subsequently, several practical and precise techniques, including solid nuclear magnetic resonance, Raman, Fourier-transform infrared, and X-ray photoelectron spectroscopies, transmission electron microscopy, and selected area electron diffraction, to characterize the GDY structure are discussed. Next, we elucidate the unique structural and electronic properties of GDY using both theoretical frameworks and experimental methodologies. Finally, we comprehensively discuss the recent applications of GDY in various fields, including biomedicine, electronics, optoelectronics, energy storage, and catalysis.

Nanomaterials have emerged as an active area of research. This is because of their broad spectrum of applications such as sensors, white light emitting diodes (LEDs), electronic displays, and other optoelectronic devices in the optics and electronic industries owing to their size- and shape-dependent properties. The synthesis technique plays a crucial role in tuning the size and shape of the materials. Herein, we briefly describe these nanomaterials' fundamental aspects, properties, and applications. Various nanomaterial synthesis methods are discussed. Their advantages and disadvantages are highlighted in conjunction with the criteria for selecting a synthesis method. The principle underlying the sonochemical method and its applicability in synthesizing diverse sub-15 nm size nanoparticles (NPs) are presented. The main objective of this article is to review recent studies on lanthanide-doped nanophosphors and the various parameters that play key roles in achieving optimum luminescence emission. Both down-conversion and up-conversion mechanisms are discussed. The importance of the combinations and concentrations of the synthesizer/activator, color tuning, and host material are emphasized.

Electrocatalytic water splitting is a green and sustainable solution for hydrogen production, but its overall performance is still limited by the sluggish and inefficient oxygen evolution reaction (OER). Here, we report the controlled growth of vanadium-iridium oxides (VIrO_x) on the surface of graphdiyne (GDY) to generate well-defined interfaces between GDY and VIrO_x. The scanning electron microscopy and high-resolution transmission electron microscopy images showed the successful growth and uniform distribution of VIrO_x quantum dots on the surface of the GDY nanosheets. The X-ray photoelectron spectra revealed that efficient charge transfer occurred at the interfaces between GDY and VIrO_x quantum dots and led to the formation of mixed-valence metal species. These catalyst advantages notably increased the number of active sites and improved the overall intrinsic activity of the system, resulting in excellent electrocatalytic OER performance with a low overpotential of 121 mV at 10 mA cm⁻², high turnover frequency of 0.914 s⁻¹ at 300 mV, and long-term stability (100 h at 100 mA cm^-2) in alkaline electrolytes.

Electrocatalytic reduction of nitrates plays a crucial role in ammonia (NH₃) production. In this study, a novel cuprous oxide/graphdiyne (Cu₂O/GDY) electrocatalyst was synthesized by growing Cu₂O/GDY on a Cu substrate with a porous architecture capable of increasing the number of active sites and enhancing mass transfer ability. The sp-C-Cu bonds between Cu₂O and GDY facilitate rapid charge transfer and promote direct electron transport from active sites to reaction intermediates. Consequently, the electrocatalyst exhibits high NH₃ production performance with a yield rate (Y_NH3) of 652.82 µmol h⁻¹ cm⁻² and Faradaic efficiency of 82.98% at −1.8 V (vs. SCE) under ambient conditions in an aqueous solution. This work introduces a novel and efficient approach for the in situ fabrication of self-supported heterostructures, thereby enabling high-performance ammonia production under ambient conditions.

The enhancement of the photocatalytic activity of graphitic carbon nitride (g-C₃N₄) depends on the rational design of its visible-light harvesting and charge separation/migration properties. Herein, an oxygen doping-induced intramolecular electron acceptor system enabling n→π* electronic transitions in red g-C₃N₄ nanosheets (E_g ∼ 1.89 eV) was prepared via copolymerization with nitrilotriacetic acid (NTA) and urea. The n→π* electronic transition can be controllably tuned, thus broadening the absorption spectrum of the system to ∼750 nm. Simultaneously, doping with oxygen which acts as an electron acceptor, accelerates in-plane charge separation and migration. Moreover, this strategy was confirmed experimentally to be scalable for industrial mass production. Experiments and theoretical calculations demonstrated that the oxygen doping could continuously modulate the band gap (from ∼2.65 to ∼1.32 eV), resulting in the formation of an intramolecular electron acceptor system which enhances charge separation/migration kinetics. The optimized sample exhibited remarkable photocatalytic H₂ and H₂O₂ production rates of ∼144.8 µmol/h and ∼539.76 µM/h, respectively, which are higher than those for currently available g-C₃N₄-based photocatalysts. Significantly, the sample exhibited H₂ and H₂O₂ photocatalytic yields ∼37.3 and ∼30.1 times those of pristine g-C₃N₄ under long-wavelength excitation (λ = 520 nm). This study developed an effective and scalable strategy for the design and synthesis of full-spectrum photocatalysts for a broad range of applications.

Recently, the synthesis of new gas-sensitive materials for use in resistive humidity sensors has attracted considerable interest. In the study, copper-containing metal-polymer nanocomposites were obtained by thermolysis of copper fumarate (I) and its complexes with 2,2′-dipyridyl (II) and 1,10-phenanthroline (III). The nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy, elemental analysis, energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The most common particle sizes of the thermolysis products of compounds I, II, and III were 18.7, 8.3, and 20.7 nm, respectively. The manufactured sensor samples exhibited good sensitivity to the relative humidity (RH) of air: 2.48%/%RH, 3.77%/%RH, and 3.11%/%RH for the thermolysis products of compounds I, II, and III, respectively. Because of the high porosity and moisture absorption of the film, the maximum sensitivity was approximately 0.005 MΩ/%RH, which indicates fairly effective behavior of the film with respect to humidity. The response and recovery times were 23.7, and 37.3 s; 24.7, and 35.8 s; 32.4, and 58.4 s, respectively. The experiment had 88%-97% reproducibility. The fabricated sensors have great potential as humidity-sensing elements for humidity monitoring.

Herein N₂O decomposition over LaMO₃ (M: Fe, Co, Ni) mixed oxides with perovskite structures has been optimized. The influence of the organic additive and the additive to (La³⁺ + Co²⁺) molar ratio on phase composition, particle aggregate size, textural properties, and catalytic activity of LaCoO₃ has been determined for the first time. Glycine improved the phase purity of LaCoO₃, enhanced the specific surface area and pore volume, and shifted the pore size distribution to the wider mesopore and macropore regions. LaCoO₃ showed better activity than LaFeO₃ and LaNiO₃ owing to the greater reducibility of Co³⁺ and its large specific surface area, and correlations between the La³⁺:Co²⁺ molar ratio, particle aggregate size, pore volume for pores larger than 25 nm, and N₂O decomposition activity for LaCoO₃ have been determined. Changes in the LaCoO₃ textural properties following catalytic experiments with 10% water vapor added to the feed have also been analyzed here-in.

Humidity sensors are widely used in various fields of research. However, continuous power supplementation remains a significant challenge for further development. Harvesting energy directly from the ubiquitous atmospheric moisture to provide a sustainable water source is a promising strategy for developing self-powered systems. In this study, we developed a self-powered humidity sensor based on a flexible fabric substrate modified with graphdiyne oxide with a significant oxidation gradient. The device produces a high voltage of approximately 0.55 V with a 7.0 µA current through spontaneous adsorption of water molecules from the ambient atmosphere. At 100% relative humidity, the device exhibited long-term and cyclic output stabilities. Compared to other carbon materials, the low conductivity of graphdiyne enables an extremely high gradient of oxidation through moisture-electric field annealing polarization. Additionally, the large water uptake of graphdiyne oxide enhanced the sensing performance of the self-powered humidity sensor. This study demonstrates the significant potential of graphdiyne oxide in self-powered sensing applications.

β-amyloid (Aβ) deposits are the leading cause of Alzheimer's disease. Many studies have confirmed that transthyretin (TTR) inhibits the cytotoxicity of Aβ oligomers (AβOs) with various species (oligomers and protofibrils, but not monomers) through their interactions. Here, we investigated the mechanisms of interactions between the TTR tetramer and various Aβ species, including two monomers with different morphologies and four oligomers with different molecular weights, by employing molecular dynamics simulations. From these results, we propose a clear interaction scenario: upon AβO binding, the dimer−dimer distance of TTR increases and the binding energy decreases, indicating an unfavorable effect on the TTR stability. Moreover, the larger the molecular weight (MW) of AβO, the greater the effect of interaction between the TTR tetramer and Aβ oligomer, and consequently the worse the TTR stability. In turn, Aβ-Aβ intermolecular distances in AβO grow and the hydrophobic solvent-accessible surface area (SASA) increases, whereas the number of intermolecular hydrogen bonds decreases, indicating AβO disaggregation induced by the TTR binding. Moreover, a trend is observed for the disaggregation to increase as the MW of the AβO species increases. Finally, we reveal that conformations rich in helical sections rather than the semi-extended conformation are favored upon binding with TTR. Overall, this study provides a comprehensive molecular-level insight to better understand the mechanism and principles of interaction between the TTR tetramer and AβOs.

The substitution of precious metals, such as ruthenium and iridium, to boost the performance of the electrocatalytic water oxidation reaction (OER) is of paramount importance in energy science and technology. However, despite recent advances, the development of nonprecious metals for the OER is still hindered by their high overpotentials, sluggish kinetics, and inadequate stability. Optimization of the electronic structure of non-precious transition metal nanomaterials plays a crucial role in enhancing their performance in the electrocatalytic OER. In this study, we employed a facile reduction method for the in situ loading of nickel nanoparticles onto graphdiyne (GDY) and obtained the Ni NPs/GDY catalyst. Due to the distinctive chemical and physical properties of GDY, its combination with nickel nanoparticles results in strong electronic interactions, effectively modulating the electronic and geometric structures of the Ni NPs/GDY catalyst and significantly improving its electrocatalytic performance in the OER. The Ni NPs/GDY catalyst exhibited a low overpotential of 294 mV at a current density of 10 mA cm⁻² and a small Tafel slope of 56.8 mV dec⁻¹ in 1 M KOH, along with excellent electrocatalytic kinetic properties and an ultra-long electrocatalytic stability of approximately 90 h. Compared to the reference catalysts Ni NPs and GDY, the Ni NPs/GDY catalyst demonstrated superior performance, which is primarily attributed to the electronic interactions generated upon the loading of nickel nanoparticles to GDY, which can expose more catalytic sites, facilitate charge transfer, and simultaneously prevent catalyst aggregation during the catalytic process. The findings of this work can provide new insights for exploring more efficient electrocatalysts for the OER.