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[Display omitted] • Interfacial instability of a-C:H film with 40 at.%H was revealed when sliding above 373 K by a combination of nanoscale experiment and simulation. • Exfoliation of graphitic rings led to significant wear of the interfacial atoms for a-C:H film with 40 at.%H. • Fragmentation of carbon chains was triggered when the hydrogen content was reduced to 10 at.%H to achieve a low friction state. Tribochemical reactions can modify the surface structure and chemical properties of amorphous carbon films during sliding, thereby altering their tribological behavior. Understanding the effects of temperature on the reaction process is important for the widespread application of amorphous carbon films, particularly at elevated temperatures. Upon sliding at temperatures higher than 373 K, the a-C:H film with 40 at.% H demonstrated atomic interfacial instability, disrupting the interfacial ordered structures with increased friction and wear. Reactive molecular dynamics (MD) simulations further revealed that the interfacial material transfer of hydrocarbon clusters in the a-C:H film with 40 at.% H at elevated temperatures was triggered by mechanochemical exfoliation of graphitic rings, leading to significant wear of the interfacial structures. When the hydrogen content decreased to 10 at.% H, more carbon chains were mechanochemically fragmented between the sliding surfaces to trap the interfacial atoms, resulting in stabilized, ordered structures and a low friction state. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnS superhydrophobic coating was prepared on Zinc Substrate. • solvothermal method is environmentally friendly and controllable in appearance. • This coating exhibited excellent physical self-cleaning performance. • This coating displayed outstanding chemical self-cleaning performance. The superhydrophobic photocatalytic self-cleaning coating has both physical and chemical self-cleaning properties, which has attracted wide attention of researchers in recent years. In this paper, ZnS superhydrophobic coating was prepared on the surface of zinc substrate by economic and environmental friendly solvothermal method and chemical modification method. By means of EDS, X-ray diffraction and X-ray photoelectron spectroscopy (XPS), it was proved that ZnS superhydrophobic coating was successfully formed on the surface of zinc substrate after solvothermal reaction and chemical modification. Moreover, the morphology of the coating surface was observed to be nanobeam by scanning electron microscopy, and the Cassie contact state was formed when water droplets contacted with the superhydrophobic coating surface containing ZnS nanobeam. In addition, the physical and chemical self-cleaning properties of ZnS superhydrophobic coatings were tested and their principles were explored. The results show that the nanobundle ZnS superhydrophobic coating has excellent physical and chemical self-cleaning properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Passive film composition changes during long-term passivation of Ni-Cr-X alloys. • Cr enriches in film and Ni enriches at the metal/film interface with time. • Aliovalent Mo and W enrichment in passive films occurs during Cr(III) enrichment. • Corundum forms early, while spinel forms over time by phase transformation. • The applied passivation potential and time influence spinel protectiveness. The passivation of Ni-22Cr, Ni-22Cr-6Mo, and Ni-22Cr-6Mo-3W (wt%) was characterized from 100 s to 10 days in 0.1 M NaCl in pH 4 at various potentials in the passive range. The influence of aqueous solution exposure time in NaCl (exposure aging), passivation potential, as well as Ni-Cr-X alloy composition (Mo or W) on passive film growth, composition, oxidation state, molecular identity, and inner versus outer film layering were investigated. Initial passive film formation was dominated by Ni(II). Cr(III) oxides and hydroxides tended to enrich upon formation and exposure aging. Corundum and rock salt are speculated to undergo a solid-state phase transformation to form NiCr 2 O 4 at long times under certain conditions. The concept of the time-potential-transformation diagrams to describe the evolution of passive film phases and protectiveness is introduced. Factors limiting Cr(III) enrichment were discussed. Aliovalent Mo and W ions were detected in passive films, particularly after aging. The roles of Cr enrichment, Ni depletion, and Mo and/or W aliovalent cations after oxide aging towards protectiveness to passive and localized corrosion in chloride (Cl-) solutions were discussed. [ABSTRACT FROM AUTHOR]

We obtained three types of particles with different surface characteristics, including solid silica with smooth surface and no surface group (SiO 2), mesoporous silica with rough surface and no surface group (M−SiO 2) and mesoporous silica with rough surface and surface silicon hydroxyl groups (M−SiO 2 (–OH)). Compared with SiO 2 , M−SiO 2 and M−SiO 2 (–OH) have higher friction between particles due to rough surfaces, and there is adhesion force between M−SiO 2 (–OH) particles due to the presence of hydroxyl groups on the surface. The schematic phase diagram of the ϕ - γ ̇ for three types of particles shows the difference of rheological property. [Display omitted] • The influence of surface characteristics on the suspensions was explored. • The roles of friction and adhesion forces on the suspensions were evaluated. • The ϕ - γ ̇ phase diagram was present to demonstrate the rheological difference. The surface characteristic of suspended nanoparticle is an extremely important property for the non-Newtonian behavior of shear thickening suspensions. Easy access to distinct surface characteristics and a deep understanding of the role of friction and adhesion forces remains challenging yet critical to study the suspension performance. In this work, by synthesizing mesoporous silica with different surface roughness and groups, the influence of surface characteristics on the non-Newtonian behavior of suspension is comprehensively explored. The results show that the suspensions containing particles with rough surface and hydroxyl groups on the surface have higher shear thickening power, lower critical shear rate, lower discontinuous shear thickening transition fraction and lower jamming fraction. Furthermore, the test of the first normal stress difference N 1 shows that the interparticle friction and adhesion both reduce the critical volume fraction of the transition from fluid lubrication dominance to frictional contact dominance in the suspension. This finding deepens the understanding of phase transformation mechanism, and open an approach to accelerate the advanced shear thickening suspensions design for next-generation intelligent materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu-HEO heterostructures were constructed by using Cu-containing HEO precursors. • Effects of Cu adding methods on Cu NPs size and activity of Cu-HEO were investigated. • The diffusion hysteresis effect of HEO was favor for the formation smaller Cu NPs. • Cu 0.5 -HEO shows superb photocatalytic activity and CH 4 selectivity for CO 2 reduction. The construction of metal–semiconductor heterojunction has been proven to be an effective way to improve the separation efficiency of photogenerated electrons and holes, thus enhancing photocatalytic activity of semiconductor with narrow band gap. Here, we construct a Cu-(Ga 0.2 Cr 0.2 Mn 0.2 Ni 0.2 Zn 0.2) 3 O 4 high entropy oxide (HEO) heterojunction by using Cu-containing HEO precursor, and the effect of Cu addition method on the photocatalytic performance was investigated. The results show that the addition method of Cu has a great influence on the size of Cu nanoparticles (NPs), heterojunction amount and photocatalytic activity of Cu-HEO catalysts. Cu-HEO samples prepared by direct introduction method possess much smaller Cu particles due to the uniform distribution and stronger diffusion hysteresis effect of Cu in HEO, and exhibit superior photocatalytic activity and CH 4 selectivity for CO 2 reduction. With the increase of Cu loading, the photocatalytic activity of Cu-HEO samples firstly increases and then decreases. Among these photocatalysts, Cu 0.5 -HEO obtained by the direct introduction method displays the highest CO 2 reduction activity, and the yields of CO and CH 4 reach to 5.66 and 33.84 µmol/h/g cat , respectively. This work innovatively uses HEO precursors with unique properties to construct metal-HEO heterojunctions with smaller metal particles and more active sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hierarchical heterostructure is fabricated by incorporating the TiO 2 or SiO 2 into the Fe 3 O 4 micro-flower framework. • Adjusting the content of TiO 2 and SiO 2 can effectively regulate the impedance matching. • An extremely broad effective absorption of 7.3 GHz can be achieved at a single thickness of only 2.0 mm for Fe 3 O 4 /TiO 2. Rational design of hierarchical heterogeneous structured Fe 3 O 4 toward boosted electromagnetic wave absorption (EMA) is extremely imperative and needs further exploration. In this study, we use two types of dielectric components, including TiO 2 and SiO 2 particles, as intercalations anchor in Fe 3 O 4 micro-flower framework through a sol–gel process to construct hierarchical hetero-structures. The tunable contents of anchoring particles allow the composites to retain their micro-flower structure and enable a reinforced polarization loss as well as enhanced impedance matching. As a result, both Fe 3 O 4 /TiO 2 and Fe 3 O 4 /SiO 2 exhibit excellent EMA performance. In detail, the Ti-2 possesses an effective absorption bandwidth (EAB) of 7.3 GHz (9.3–16.6 GHz) at 2.0 mm and a reflection loss (RL) of −67.1 dB at 3.78 mm. Si-2 exhibits a strong absorption with RL of −59.1 dB at 2.35 mm and an EAB of 4.8 GHz (8.3–13.1 GHz) at 2.0 mm. More importantly, an in-depth analysis confirms that the EMA of Ti-2 is superior to the previously reported results in terms of EAB, matching thickness, and absorption intensity. Therefore, this work provides a novel pathway to fabricate high-performance EMA absorbers via rational design of hierarchical hetero-structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calcination temperature has significant influence on the formation of HEO. • The increase of calcination temperature can promote element dispersion in HEO. • HEO exhibits much higher photocatalytic activity for photocatalytic CO2 reduction. High-entropy oxides (HEOs) have become very promising materials due to their excellent properties. In this work, inspired by the abundant surface defects and narrow band gaps of high-entropy oxides, a high-entropy oxide (Ga 0.2 Cr 0.2 Mn 0.2 Ni 0.2 Zn 0.2) 3 O 4 with the Fd -3m spinel structure was designed and synthesized by sol–gel method for photocatalytic CO 2 conversion. The results showed that the calcination temperature had a very important effects on the formation of high-entropy oxide, structural defects and the element dispersion. Meanwhile, (Ga 0.2 Cr 0.2 Mn 0.2 Ni 0.2 Zn 0.2) 3 O 4 HEO with appropriate calcination temperature exhibited excellent photocatalytic activity and stability for CO 2 reduction with water vapor without any co-catalyst under visible light due to its ultra-narrow bandgap (1.6 eV), abundant structural defects, uniform dispersion of metal elements and suitable band structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • A high-performance FeNi 3 and FeNi 3 @C with tunable carbon thickness were successfully synthesized. • The core–shell feature endows FeNi 3 @C with synergistic magnetic-dielectric attenuation mechanism and better impedance matching. • An extremely broad effective absorption band of 10.3 GHz occurs at a single thickness of only 2.0 mm for FeNi 3. • FeNi 3 @C obtains outstanding EMA from C to Ku band with thin thickness of 1.5–2.5 mm. The rational design of electromagnetic wave absorption (EMA) materials featured with broadband and high-efficiency in gigahertz (GHz) is still a great challenge. In this study, we prove fabricating FeNi 3 and FeNi 3 @C core–shell microspheres to solve the challenge. The as-prepared FeNi 3 microspheres exhibits extremely broad effective absorption bandwidth (EAB, RL ≥ 10 dB, > 90 % absorbing) of 10.3 GHz (7.7–18.0 GHz) at only 2.0 mm, occupying 64.4 % of the investigated frequency range with a single matching thickness. Such an outstanding EMA performances is credited to strong dielectric loss and magnetic loss. Compared with pristine FeNi 3 , the delicate design of core–shell structure and tailored synergistic effect of FeNi 3 and carbon produce positive reinforcement both in magnetic loss and dielectric loss, endowing FeNi 3 @C samples with optimized impedance matching and appropriate attenuation ability. As a result, FeNi 3 @C samples present impressive EMA performances from C to Ku band, especially for FeNi 3 @C-3, demonstrating its potential of effectively dissipates electromagnetic wave in 6.1–18.0 GHz (RL ≥ 20 dB, > 99 % absorbing) by simply regulating a thickness of 1.5–2.5 mm. FeNi 3 and FeNi 3 @C feature with optional broad bandwidth (completely covering C, X and Ku band), strong absorption, and thin thickness ensure them a superior EMA material. [ABSTRACT FROM AUTHOR]