Robust Hydrophobic Materials by Surface Modification in Transition-Metal Diborides

Abstract

Exploring the hydrophobicity of robust conductors is significant for electronic devices to simultaneously be used in a wet environment and extreme conditions. However, a combination of conductivity, strong mechanical properties, and hydrophobicity in one material is hindered by the inherent features of the materials. A new kind of robust hydrophobic conductor is designed in transition-metal diborides (TMdBs: TiB 2 , ZrB 2 , and HfB 2 ) to break through this challenge. The results calculated by density functional theory indicate that high hardness comes from high shear and bulk modulus, which is consistent with experimental results (TiB 2 , 25.0 GPa; ZrB 2 , 17.5 GPa; HfB 2 , 21.5 GPa). The theoretical calculated results reveal that edge sides have a lower surface energy than basal plane (001) in TMdBs. Hence, the edge sides are exposed with a needle-like morphology in TMdBs. Moreover, needle-like surfaces exhibiting hydrophobicity have water contact angles of 132.0°(TiB 2 ), 116.8°(ZrB 2 ), and 114.0°(HfB 2 ). The hydrophobicity arises from a lower surface free energy of edge sides in TMdBs and a rough surface that reduces the contact area of water and a solid. This work develops a new kind of robust functional material in TMdBs.

Large-Scale Manual Grinding Preparation of Ultrathin Porous Sulfur (S8)-Anchored ScOOH Nanosheets for Photothermal Conversion and Dye Adsorption

“…This result shows that S 8 /ScOOH-NSs have a hydrophobic surface, which should be due to hydrophobic sulfur and carbon components distributed on the surface. , However, S 8 /ScOOH-NRs have a more hydrophobic surface than S 8 /ScOOH-NSs, which directly results from the combination of surface sulfur/carbon components and specific surface nanostructures with hierarchical roughness (Figure a) . Such a hydrophobic surface indicates that S 8 /ScOOH-NSs have potential performances in self-cleaning, oil/water separation, and anticorrosive because of the low surface energies and droplet–surface adhesion. , …”

“…38 Such a hydrophobic surface indicates that S 8 /ScOOH-NSs have potential performances in self-cleaning, oil/water separation, and anticorrosive because of the low surface energies and droplet−surface adhesion. 39,40 Meanwhile, S 8 /ScOOH-NSs show good photothermal conversion performance. Upon an 808 nm NIR laser radiation, an obvious temperature increase is recorded (Figure 4c).…”

Robust Sandwiched B/TM/B Structures by Metal Intercalating into Bilayer Borophene Leading to Excellent Hydrogen Evolution Reaction

“…Except for charge transferring from the metal substrate, regulation like metal doping and intercalation can be also pervaded ways to afford external charge required for the stability of borophene. Several freestanding metal-borophene networks including the second and third main group elements (Mg, [48] Ca, [48] Sr, [49] Al, [50][51][52][53] Ga, [54] In [54] ), as well as partial transition metal elements (Sc, [48,55] Ti, [48,[56][57][58] V, [56] Cr, [56] Mn, [56,59,60] Fe, [61,62] Y, [48] Zr, [57,58] Mo, [63] Hf, [57,58] W, [64] Ir [65] ), have been reported. Among the transition metal borides (TMB) coexist various attractive characteristics, especially, strong mechanical properties and stability.…”

“…Therefore, one might raise the question that are there other 2D metal-borophene networks except for those reported previously? [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] What is the most stable structure? Especially, the potential catalytic application of metal-borophene networks is an interesting issue, which may offer more opportunities to search for the next generation of catalytic platforms.…”

Mechanical properties and multifunctionality of AlB2-type transition metal diborides *

“…Because different TM layers can offer different content of electrons, which can generate excellent electron transfer along layer (conductor), electrical phonon coupling (superconductor), special electronic spin state (magnetism), and unique absorption ability (catalysts). Such as TMdBs usually possess good electrical properties with great low resistivity (in the order of 10 −7 or 10 −8 Ω m) [35,36,[38][39][40][41]; Qi et al reported that the superconductivity of TMdBs has a great deal to do with the flat boron layers [42,43]; Chen et al found for the first time that the catalytic activity of MoB 2 on hydrogen evolution reaction (HER) in acidic solution was significantly higher than that of Pt/C in the range of high current density [33]. This provides a new impetus to find low-cost materials with high catalytic activity.…”