Graphene materials considered to be promising candidates for next-generation lubricants has been explored and summarized extensively, owing to their atomic-level lamellar structure and extremely low interlayer shear van der Waals barrier. However, the lubrication properties of graphene under harsh working conditions, including elevated temperature, heavy load, high vacuum, special atmosphere environment and electric or magnetic field environment, have not been systematically summarized and thoroughly analyzed. Meanwhile, the effect of graphene on the behavior of boundary tribofilm have not been systematically reviewed. This review focuses on the application of graphene family materials in harsh working conditions. Firstly, an overview of the graphene categories is presented, and then the application of graphene in harsh working conditions is summarized. Besides, the effect of graphene family materials on the behavior of boundary tribofilm is examined. Accordingly, the lubrication mechanisms of graphene are summarized, which mainly include adsorption protection of boundary tribofilm, graphene microstructural transformation, graphene internal slippage, and micro bearing rolling-sliding effect. Finally, the critical challenges and future prospects for the application of graphene as next generation lubrication materials are discussed. This article aims to boost further development of graphene as a candidate to solve the lubrication bottleneck of equipment in harsh working conditions such as space, deep sea, deep earth, nuclear energy and MEMS.

This study introduces a novel method for mica exfoliation using biaxial straining principles through H2 and N2 intercalation. Our two-stage approach combines microwave irradiation with biaxial straining triggered by H2 and N2. Our first principles simulations showed that N2 leads to a larger drop in bulk modulus per tensile strain than H2, resulting in decreased mica strain entropy (or less disordering) and ineffective exfoliation due to the resulting positive (H2) and negative (N2) Poisson ratio. Therefore, we applied H2 and performed SEM, FT-IR, and XRD analyses. The results indicate that our pre-treatment methods did not alter the mica's crystalline structure, and our two-step treatment method increased the interlayer distances of bulk mica particles. TEM analysis revealed the presence of mica nanosheets in single layers. This study represents a significant breakthrough in 2D exfoliation research not only for mica but also for non-van der Waals bonded crystals. By utilizing innovative biaxial straining principles through H2 and N2 interclation, our approach offers a promising avenue for achieving enhanced layer separation in layered materials.

Structural absorption is reported to be responsible for the deep black appearance of numerous living organisms, including butterflies, birds, and spiders. Here, we report the presence of structural absorption in the beetle Euprotaetia inexpectata, which has reflectivity values as low as 0.1% and absorptivity values as large as 99.5%. By combining ultrastructural studies and full-wave optical simulations, we show that the black appearance of this beetle is generated by arrays of anisotropic micropillars, which enhance absorptivity through a combination of optical focusing and Mie scattering. These results highlight the independent evolution of black surfaces in nature and provide interesting templates for bio-inspired applications.

Bioadhesives comprising of catechol crosslinkers have displayed broad utility against both soft and hard substrates. However, catechol's two-part adhesion chemistry requires oxidative chemicals that are detrimental to organic substrates. Herein, a water-activated adhesive with inherent antibacterial properties is prepared by grafting catechol groups onto branched polyethylenimine (PEI-DBA20). The resultant PEI-DBA20 is stable in organic solvents but undergoes curing in the presence of water. The in-built oxidation method relies on the close proximity of catechol/Schiff base functional groups that form tautomers in the presence of aqueous solvents. The curing mechanism is demonstrated by dip coating hydrated substrates, where the grafted dendrimers subsequently crosslink and form thin films. Coated PET films and polyester textiles exhibit an antimicrobial surface with 4–6 log reduction against model Gram-negative bacteria.

Photodetection of organic-inorganic hybrid heterostructures from visible to invisible ultraviolet and infrared rays is revisited with respect to their material properties aspect, device structure, and emerging applications. The approach of organic-inorganic hybrid heterostructures using two or more varied materials has been extensively attempted as the emergence of broadband photodetection covering multi-colors as well as ultraviolet to infrared rays has ignited considerable interest in new applications. This review provides a timely overview of the scientific relationship between materials engineering and incident light properties, a systematic classification of representative material combinations, and a particular focus on each principle's insights. We also summarize recently-presented applications in organic-inorganic hybrid heterostructure-based photodetectors according to the target light wavelength.

Hematite as a catalyst for photoelectrochemical water splitting offers huge potential, due to its high chemical stability, great abundance, and low cost. However, the low water oxidation kinetics and poor charge transportation have hindered progress towards the manufacture of practical water splitting devices. To tackle these problems, a visible light responsive metal-organic framework (MOF) polyhedral zeolitic imidazolate (ZIF-67), and optimised plasmonic Ag nanorods were incorporated into hematite nanostructures to form a three-component heterojunction photoelectrode. The designed photoanode showed dramatically improved light harvesting in the visible range and enhanced charge transport. A mechanistic investigation allowed the deconvolution of the enhanced performance pathways. First, the Hematite@ZIF-67 core-shell p-n junction enables facile charge carrier transfer between ZIF-67 and hematite. In addition, ZIF-67 also provides active sites for water oxidation and boosts surface oxygen evolution reaction (OER) kinetics. Guided by finite-difference time-domain (FDTD) modelling, Ag nanorods with optimised aspect ratio were incorporated between ZIF-67 and hematite. The Ag nanorods facilitate broadband light absorption and surface charge injection, induced by near-field excitation enhancement and plasmonic resonance energy transfer (PRET) pathways. The design and addition of ZIF-67 and Ag nanorods result in superior performance for a hematite-based photoanode for photoelectrochemical (PEC) water oxidation.

This work prepared porous carbon with excellent electrochemical performance using hydrothermal and carbonization methods. Specifically, caragana was used as carbon precursor, hydrazine hydrate as nitrogen source, and nickel acetate as nickel source during this preparation process. The results showed that porous carbon carbonized at 700 °C has excellent surface area (1779 m2 g−1), moderate oxygen content (7.88 at%), and nitrogen content (1.64 at%), which are conducive to improving pseudocapacitance. The N4NiPC180-3 has specific capacitance of 427 F g−1 at 0.5 A g−1, and high capacitance retention of 74.3% even at 20 A g−1. The retention rate after 10,000 cycles is 97.4%, verifying its excellent cycling stability. In addition, the N4NiPC180-3 in the two-electrode system test can achieve an energy density of 35.8 W h kg−1 at a power density of 500.1 W kg−1. This work extends high value-added utilization of biomass derivatives in energy storage applications.

We introduce four new biocompatible toxic element-free Ti-based metallic glass (MG) compositions with constant metalloid (Si10B5) and varying precious metal (PM) contents for simultaneous improvement in glass-forming ability (GFA) and corrosion properties. Being completely free from cytotoxic elements like Cu, Ni, or Be, which are indispensable for Ti-based bulk metallic glass production, limits the GFA of the studied alloys significantly. However, avoiding these elements also realizes an unprecedented corrosion resistance in simulated body fluids, which supports the potential utilization of the alloys as long-lasting dental implant material. The novel Ti60Zr15Si10B5Pd10, Ti60Zr15Si10B5Pt10, Ti60Zr15Si10B5Pd5Pt5, Ti60Zr15Si10B5Pd5Au5 alloys are obtained in ribbon form using conventional single-roller melt spinning. The effect of the PM additions on the GFA and corrosion resistance of the alloys is investigated comparatively with each other by synchrotron X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and cyclic polarization tests. Further, their Vickers hardness values are deduced using an ultra-sensitive micro indentation method, and the findings are discussed based on the composition dependence. It was found that the Ti60Zr15Si10B5Pd5Pt5 alloy presents a promising GFA while showing outstanding corrosion resistance in a simulated body fluid at 310 K.

Herein, we describe for the first time the synthesis of the highly porous Hf-tetracarboxylate porphyrin-based metal-organic framework (MOF) (Hf)PCN-224(M) (M = H2, Co2+). (Hf)PCN-224(H2) was easily and efficiently prepared following a simple microwave-assisted procedure with good yields (56–67%; space-time yields: 1100–1270 kg m−3·day−1), high crystallinity and phase purity by using trifluoromethanesulfonic acid and benzoic acid as modulators in less than 30 min. By simply introducing a preliminary step (10 min), 5,10,15,20-(tetra-4-carboxyphenyl)porphyrin linker (TCPP) was quantitatively metalated with Co2+ without additional purification and/or time consuming protection/deprotection steps to further obtain (Hf)PCN-224(Co). (Hf)PCN-224(Co) was then tested as catalyst in CO2 cycloaddition reaction with different epoxides to yield cyclic carbonates, showing the best catalytic performance described to date compared to other PCNs, under mild conditions (1 bar CO2, room temperature, 18–24 h). Twelve epoxides were tested, obtaining from moderate to excellent conversions (35–96%). Moreover, this reaction was gram scaled-up (x50) without significant loss of yield to cyclic carbonates. (Hf)PCN-224(Co) maintained its integrity and crystallinity even after 8 consecutive runs, and poisoning was efficiently reverted by a simple thermal treatment (175 °C, 6 h), fully recovering the initial catalytic activity.

The native amorphous silicon oxide (SiO2) layer formed on the Si substrate leads to the (100) preferred orientation for β-phase gallium oxide (β-Ga2O3), which encounters various defects in β-Ga2O3, such as twin boundaries and stacking faults etc. The (111) preferred orientation of titanium nitride (TiN) hetero-buffer layer can be used in the interface between β-Ga2O3 and Si substrates to reduce the lattice mismatch between them and increase the (˗201) preferred orientation for β-Ga2O3. The lattice mismatch between TiN (111) and β-Ga2O3 (˗201) is 0.76%, which is less than the β-Ga2O3 (˗201)/Si (111) about ˗6.3%. The β-Ga2O3 and TiN films were grown using radio-frequency magnetron sputtering on Si substrates, which possess polycrystalline nature as revealed using X-ray diffraction patterns and high-resolution transmission electron micrographs. The optimal parameters are found as, process atmosphere: Ar = 10 sccm, RTA: 800 °C for β-Ga2O3/TiN (300 nm)/Si. This work highlights the effect of the TiN hetero-buffer layer, the process atmosphere, and annealing temperatures on the microstructural and surface morphology of β-Ga2O3 films. The lateral Schottky barrier diode (SBD) were fabricated using the optimized β-Ga2O3/TiN (300 nm)/Si film. The Baliga's Figure of Merit (BFOM) of the lateral SBD is 7.60 × 10−2 kW/cm2, which exhibits 4 order of BFOM higher than that of β-Ga2O3/Si SBD due to interface engineering. The β-Ga2O3/TiN (300 nm)/Si hetero-structure demonstrates a promising material to be employed in the next generation β-Ga2O3 based power devices.

The size range of an atom is approximately 3–5 Å (10−10 m), while a nanometer is 10−9 m. Thus, nanomaterials are used as multipliers that can be used to attach several single atoms to the surface. It is similar to an exquisitely-arranged production line, with every single atom acting as an operator, working on each catalytic reaction. As applied to biological applications, these catalytic targets become proteins in vivo, and the transformation of nanomaterials into single-atom catalytic enzymes illustrates the potential of the new single-atom nanozyme (SAN) nanotechnology for biological applications. As SAN materials on the order of 1 nm–100 nm are selected as carriers, such as carbon quantum dots and metal-organic frameworks, they can load single atoms and make their reaction efficiency much higher than that of regular enzymes. Moreover, the support materials have the optical property of absorbing the radiation that allows the nanocomposite to influence the behavior of the chemical reactions. In this review, we present novel SANs that can both increase the catalytic rate and produce diagnostic and therapeutic effects.

Recently, laser powder bed fusion of nitinol alloys (LPBF-NiTi) has attracted much attention due to its ability to precisely form complex parts. However, the wear and corrosion resistance is crucial for practical applications of LPBF-NiTi alloys. Rare earth oxides are common additives used to improve the surface properties of alloys. In this work, nano-sized cerium oxide (CeO2) is selected as the additive, and the influence rule and mechanism of different addition amounts of CeO2 on the surface properties of LPBF-NiTi alloy are deeply studied. The results showed that the addition of an appropriate amount of CeO2 (0.03 wt% CeO2 addition) could effectively refine the grains and improve the grain order, which achieved the improvement of the mechanical properties (tensile strength and toughness) of the LPBF-NiTi alloy. Furthermore, the reduction in friction coefficient and wear scar depth/width proved that the addition of CeO2 effectively improves the wear resistance of LPBF-NiTi alloys, which were mainly attributed to the synergistic action of the precipitation of the secondary hard phase (NiCe), the grain refinement strengthening, and stable phase transformation brought about by high latent heat of transformation. In addition, the improvement of anti-corrosion was reflected in the reduction of corrosion current density Icorr and pitting pits, mainly due to the formation of NiCe precipitates and grain refinement, which effectively hindered the propagation and extension of pitting corrosion. Most significantly, the 0.03% CeO2 sample achieved the simultaneous improvement of mechanical properties and surfaced functional properties, which greatly expanded the application prospects of NiTi–CeO2 alloys.

In this work, we have fabricated a highly sensitive direct irradiating X-ray photodetector (DXPD) based on Zinc Gallium Oxide (ZnGa2O4) epilayers with a metal-semiconductor-metal structure. The ZnGa2O4 epilayers were grown on a c-plane sapphire substrate by metalorganic chemical vapor deposition (MOCVD). To test the DXPD's capabilities, we subjected it to a synchrotron hard X-ray source with an energy of 10 keV, and measured incident radiation flux ranging from 5.7✕107 to 4.6 ✕1011 counts/sec. The effect of changing the applied bias voltage on the time response of the DXPD was investigated. The sensitivity of hard XPDs was compared using gallium oxide (β-Ga2O3) epilayer grown by MOCVD. The results showed that ZnGa2O4 DXPD had approximately 104 times greater sensitivity than the β-Ga2O3 based XPD. ZnGa2O4 based detectors also exhibited remarkable sensitivity of 2.87 × 109 μC Gyair−1cm−2 for the incident flux of 5.7✕107 counts/sec at 15 V. Additionally, the sensitivity was examined in terms of applied bias and dose rate. Based on these observations, it can be concluded that ZnGa2O4 epilayers grown by MOCVD hold immense potential for use in high-performance hard XPDs.

GaGeTe is a layered topological semimetal that has been recently found to exist in at least two different polytypes, α-GaGeTe (R3¯m) and β-GaGeTe (P63mc). Here we report a joint experimental and theoretical study of the structural, vibrational, and electronic properties of these two polytypes in high-pressure conditions. Both polytypes show anisotropic compressibility and two phase transitions, above 7 and 15 GPa, respectively, as confirmed by XRD and Raman spectroscopy measurements. Although the nature of the high-pressure phases could not be confirmed, comparison with other chalcogenides and total-energy calculations allow us to propose possible high-pressure phases for both polytypes with an increase in coordination for Ga and Ge atoms from 4 to 6. In particular, the simplification of the X-ray pattern for both polytypes above 15 GPa suggests a transition to a structure of relatively higher symmetry than the original one. This result is consistent with the rocksalt-like high-pressure phases observed in parent III-VI semiconductors, such as GaTe, GaSe, and InSe. Pressure-induced amorphization is observed upon pressure release. The electronic band structures of α-GaGeTe and β-GaGeTe and their pressure dependence also show similarities to III-VI semiconductors, thus suggesting that the germanene-like sublayer induces a semimetallic character in both GaGeTe polytypes. Above 3 GPa, both polytypes lose their topological features, due to the opening of the direct band gap, while the reduction of the interlayer space increases the thermal conductivity at high pressure.

Growing three-dimensional (3D) materials on two-dimensional (2D) van der Waals surface has shown its effectiveness in overcoming materials incompatibility for stacking transferrable membranes toward advanced device manufacturing. Herein, we demonstrate that the nucleation of hexagonal germanium (Ge) grains within a continuous crystalline film, which has been unfeasible through traditional epitaxy techniques, is realized by chemical vapor deposition on top of n-type monolayer molybdenum disulfide (MoS2) substrates. Suggested by quantum molecular dynamics calculation, the hexagonal Ge nucleation is thermodynamically preferable to cubic Ge when growing on monolayer MoS2 with sulfur vacancies. The strained hexagonal Ge grains have been confirmed by transmission electron microscopy analyses from both real space and reciprocal space. Scanning probe microscopy shows that the hexagonal Ge film possesses higher reflectivity in infrared spectral range, implying a higher carrier concentration resulted from the narrower band gap, as compared to cubic Ge.

We developed a carbon dioxide (CO2)-responsive supramolecular drug carrier system through a combination of hydrophobic CO2-sensitive imidazole-containing rhodamine 6G (I–R6G) as an efficient anticancer agent and hydrophilic ureido-cytosine (UrCy) end-capped polyethylene glycol (UrCy-PEG) as a self-assembled nanocarrier that could potentially enhance the safety and efficiency of cancer treatment. Owing to the self-complementary quadruple hydrogen bonding interactions between the UrCy moieties at the polymer chain ends, UrCy-PEG can spontaneously self-assemble into spherical-like nanoobjects in water that can effectively encapsulate hydrophobic I–R6G and form co-assembled nanoparticles with tunable sizes (depending on the I–R6G loading content). These nanoparticles display several notable physical features, including high structural stability in normal physiological aqueous media or red blood cell-containing media, unique CO2-responsiveness, and controlled CO2-sensitive I–R6G release. In vitro cytotoxicity assays clearly indicated I–R6G-loaded nanoparticles exerted selective cytotoxicity towards cancer cells, but had no adverse effects on normal cells. I–R6G-loaded nanoparticles exerted significantly higher levels of cytotoxicity at lower doses in CO2-treated cell culture media compared to I–R6G-loaded nanoparticles in pristine media. More importantly, cellular assays demonstrated that—in comparison to I–R6G-loaded nanoparticles in pristine media—CO2-treated culture media accelerated macropinocytic internalization of I–R6G-loaded nanoparticles into cancer cells, and subsequently led to more rapid induction of apoptosis in cancer cells and massive programmed cell death. Thus, this newly created system may act as a potential route to manipulate the drug delivery and release performance of self-assembled nanobjects for efficient cancer therapy.

Upconversion nanoparticle (UCNP)-driven polymerization attracts great attention due to the ability of near-infrared light to penetrate deeper into biological media and synthetic materials than ultraviolet or visible light. Despite significant progress, the limitation of near-infrared light-triggered polymerization is associated with a key element of the photocurable composition, a UCNP/photoinitiator complex or a nanoinitiator. To determine the impact of resonance energy transfer from UCNPs to photoinitiator (PI) and its effect on polymerization, we developed two different photocurable compositions consisting of the polyethylene glycol diacrylate (PEG-DA), ultraviolet- and blue-emitting NaYF4: Yb3+, Tm3+ UCNPs with hydrophobic surface combined with water-soluble or insoluble PI. We found that transfer energy in these nanoinitiators proceeds differently: in UCNP/water-soluble PI (lithium phenyl-2,4,6-trimethylbenzoylphosphinate or LAP), it occurs through the photon-mediated transfer while in UCNP/water-insoluble PI (2-benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone or Irgacure 369), it takes place via the non-radiative resonant energy transfer. The impact of these processes in homolytic decomposition of initiator is extremely important in terms of the precisely controlled fabrication of polymer structures. PEG-DA facilitates the affinity between hydrophilic and hydrophobic components of the photocurable composition, which provides UCNP-driven cross-linking of biopolymers such as methacrylated hyaluronic acid and gelatin. 3D structures were prototyped to demonstrate the one-step rapid procedure of nanoinitiator preparation and emphasize the control of the energy transfer in UCNP/PI complexes for further development of UCNP-driven polymerization.

Bone tissue repair is influenced by the synergistic interaction between acute immune microenvironment and osteogenesis. In this study will be independently by film dispersion method and static loading shell polymers and resveratrol liposome preparation CS - Res @ Lipo (CRL) and microfluidic technology preparation of HAMA@HepMA hydrogel microspheres (MS) by condensation reaction of chemical grafting, and then the non-covalent binding site of the MS microsphere was used to skillfully bind BMP-2, construct procedural release of hydrogel microspheres (CRL @ BMP - 2 @ MS). CRL@BMP-2@MS inhibit the acute immune peak by rapidly releasing Res, in addition, the sustained liberation of BMP-2 synchronizes osteoimmunity and osteogenesis, thereby accelerating bone repair. The results showed that Res was released with an increased cumulative rate of 72.4 ± 3.6% in the first 24 h, TNF-α and IL-1β levels were significantly decreased by 4.27 times and 3.65 times as compared to the control group, respectively. Furthermore, continuous release of approximately 40.26 ± 6.8% of BMP-2 occurred within the first 72 h, CRL@BMP-2@MS microspheres significantly increased osteogenic activity compared with the control group by 2.98 and 2.82 times, respectively. In conclusion, the programmed CRL@BMP-2@MS constructed in this study can realize the programmed synergistic linkage of immunity and osteogenesis, dynamically regulate bone repair, and the treatment of clinical bone repair will be based on a new strategy for diagnosis and treatment.

The quantum effects confined in the ultimate two-dimensional limit are able to address the challenges and provide advances in high-performance spintronic devices. In the paper we show a successful strategy to enrich the electronic properties of thallene, a new honeycomb analogue of graphene, through the interface engineering, which opens a great potential of thallene as an advanced spintronics material. While the thallene has been experimentally realized recently on NiSi2/Si(111) substrate, there remains a lack of attractive electronic properties due to the strong thallene-substrate coupling. This challenge is addressed here through the decoration of thallene/NiSi2 interface by Sn interlayer, which allows to eliminate the thallene-substrate coupling and produce a high-quality large-scale thallene monolayer with exotic electron bands demonstrating colossal spin-polarization just above the Fermi level. It is demonstrated that appropriate electron doping or external electric field are enable the spin-transport regime. The discovered band structure regulation boosts the functionality of the 2D-Tl Xene and makes it a highly attractive material for spintronics applications.

Clinical radiotherapy (RT) is severely limited by hypoxic tumor microenvironment and a lack of targeting precision. Therefore, it is crucial to develop highly efficient radiosensitizers to enhance RT efficacy. Herein, a novel kind of epidermal growth factor receptor (EGFR)-antagonistic affibody-functionalized Pt-based nanozyme for RT sensitization to EGFR-positive tumors was developed. In this study, porous platinum nanoparticles (pPt NPs) featuring catalase (CAT)-like activity and strong radiation energy absorption ability were first synthesized. Then, a thin biomimetic polydopamine (PDA) layer was coated on pPt NPs to optimize its biocompatibility as well as provide a reactive surface. Finally, a dimeric EGFR-antagonistic affibody called ZEGFR expressed by the Escherichia coli (E. coli), was conjugated to pPt@PDA NPs (termed pPt@PDA-ZEGFR NPs) to precisely recognize EGFR-positive A431 tumors. Under the navigation of ZEGFR, superior tumor homing was achieved with these Pt-based nanozymes, which was ascribed to EGFR receptor-mediated endocytosis. As high-Z metal NPs exhibit an inherently strong ability to absorb radiation energy and catalyze endogenous H2O2 in tumors, the pPt@PDA-ZEGFR NPs demonstrated superb therapeutic efficacy; specifically, the NPs significantly inhibited HIF-1α expression and increased RT-induced DNA damage. Furthermore, the biosafety of these Pt-based nanozymes was good during short-term treatment. In summary, EGFR-antagonistic affibody-functionalized Pt-based nanozymes are promising radiosensitizers for the precise therapy of EGFR-positive tumors.