Enhanced Thermal Conductivity of 5A Molecular Sieve with BNs Segregated Structures

Abstract

5A molecular sieves have been widely used as adsorbents in cryogenic distillation for hydrogen isotope separation in fusion reactor engineering, but its low thermal conductivity is detrimental to the process stability. Improving the thermal conductivity of 5A molecular sieves is one of the most important goals for high-performance devices. Here, firm segregated structures with boron nitride sheets (BNs) are constructed around 5A molecular sieve particles. SEM results show 30 mm BNs tend to form the better networks in comparison with that of 0.12 mm BNs at 40 wt% loadings. It is further verified that BNs with the larger size promote the thermal conductivity. Meanwhile, the thermal conductivity increases with the increasing amounts of BNs. XRD and specific surface area results indicate that the sintering and the addition of BNs exert negligible effects on the structure of 5A molecular sieve. These results indirectly show 5A molecular sieve with BNs segregated structures is very likely to be used for the application of hydrogen isotopic separation. Besides, this work provides new insight into the construction of segregated structure in inorganic porous materials.

Ion-imprinted modified molecular sieves show the efficient selective adsorption of chromium(vi) from aqueous solutions

“…The characteristic peaks of ZMS-5A are in good agreement with the reported data. 35,36 The modication by APTES did not change the crystal structure of ZMS-5A. However, most of the sharp characteristic diffraction peaks of IIZMS-APTES disappeared.…”

Kinetic studies on acidic wet chemical etching of silicon in binary and ternary mixtures of HF, HNO3 and H2SiF6

“…Even for the ternary etching mixtures of HF, HNO 3 and H 2 SiF 6 used in the PV industry for acid texturing, there is no sufficient systematic background in the literature data to be able to provide any reliable conclusions about kinetic models. Rather, numerous literature references [20][21][22][23][26][27][28][29][30][31][32][33][34]36,41 can be summarised as an empirical search for the optimum etching bath composition and the optimum reaction conditions to generate specific surface morphologies, without paying particular attention to the etching mechanism.…”

“…24,25 Accordingly, the literature is predominantly focused on the generation of defined surface morphologies (e.g., polish or texture etching) using empirically selected compositions of etching mixtures. [20][21][22][23][26][27][28][29][30][31][32][33][34]36,41 A decisive parameter is the mass transport through a stagnant liquid film (diffusion boundary layer), 5,24 represented on the one hand by the mass transfer of the reactants from the solution to the silicon surface, followed by the effective chemical reactions at the Si surface, and on the other hand by the transport of the products from the silicon surface into the solution. Depending on which step offers the higher resistance, the overall reaction is reaction or mass transfer controlled.…”

A Grain Orientation‐Independent Single‐Step Saw Damage Gettering/Wet texturing Process for Efficient Silicon Solar Cells

“…[ 8 ] These techniques are relatively expensive and introduce lattice damages in the region close to the etched surfaces, thus requiring an additional damage removal‐etches process. [ 9 ] Wet texturing methods include additive‐based texturing, [ 10,11 ] such as metal‐catalyzed chemical etching (MCCE) [ 12 ] and metal‐assisted catalyzed etching (MACE). [ 13 ] These methods cause environmental pollution and metal ion contamination on the wafer surface, and are more expensive than conventional process that uses hydrofluoric and nitric acid (HF‐HNO 3 ).…”