Nano Energy
·
2017
·
IF 12.343
Yafei Cheng,Xing Fan,Fan Liao,Shunkai Lu,Youyong Li,Liangbin Liu,Yanqing Li,Haiping Lin,Mingwang Shao,Shuit-Tong Lee
The development of highly efficient electrocatalysts for hydrogen evolution reaction is a fundamental undertaking of the hydrogen economy . Herein, we investigated the electrocatalytic performance of M/Si (M = Os, Rh, Pt, Pd, Re, Ru, Au or Ag) nanocomposites for hydrogen evolution reaction. The results show that Os/Si nanocomposites exhibit the best catalytic efficiency with a negligible onset overpotential (−25 mV), a small Tafel slope of −24 mV dec −1 and remarkable long-term stability. Of most importance, at a current density of the typical industrial production (−1000 mA cm −2 ), the energy conversion efficiency of the Os/Si nanocomposite is 29.3% higher than that of the commercial 40 wt% Pt/C. The density functional calculations reveal that such outstanding catalytic activity of the Os/Si catalyst arises from the thermodynamically more favorable hydrogen adsorption free energy (Δ G H* = −0.03 eV) at the osmium/silicon interfaces than that on platinum (Δ G H* = −0.09 eV) or osmium (Δ G H* = −0.26 eV).
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Nanoscale
·
2017
·Vol. 9
·期 28
·10138-10144
·
IF 7.367
Binbin Jiang,Fan Liao,Yuyang Sun,Yafei Cheng,Mingwang Shao
Cost-effective catalysts for electrocatalytic water splitting play a key role in the renewable energy research. Although Pt has been regarded as the best catalyst, its wide applications have been impeded by its high cost and scarce natural abundance. Therefore, decreasing the Pt usage for electrocatalyst design is significant toward the hydrogen evolution reaction (HER). Herein, flower-like Pt nanocrystals were loaded on the surface of nitrogen-doped graphene using Si nanowires as the sacrificial template. The experimental results showed that the optimal Pt nanocrystals/N-doped graphene with superior HER activity and excellent stability only has a low Pt loading of 5.0 wt%. It is noted that the HER mass activity of the Pt nanocrystals/N-doped graphene is 5 fold higher than that of the 20.0 wt% Pt/C commercial catalyst. This optimal catalyst also achieved a low Tafel slope (28.0 mV dec−1), large apparent exchange current density (0.989 mA cm−2) and high turnover frequency (2.05 s−1). This work may provide an effective avenue for developing highly efficient electrochemical catalysts for the HER.
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CEMENT AND CONCRETE RESEARCH
·
2024
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IF 10.9
Binmeng Chen,Xu Fang,Yuyang Zhao,Zongjin Li
In recycling and reusing construction waste, carbonation of recycled concrete fine (RCF) has been successfully applied to produce value-added products, such as silica nanoparticles, via the breaking of calcium silicate hydrate (C-S-H) structure and condensation of silicate chains. However, the intricacies of carbonation of RCF with varying calcium to silicon (C/S) ratios and their implications on the size of generated silica nanoparticles remain unknown. In this work, we developed an optimized carbonation method at high water to solid ratio to fabricate silica nanoparticles from C-S-H with different C/S ratios. The particle size of silica nanoparticles was found to gradually decrease with the increased C/S ratio of C-S-H. Since as C/S ratio increased, silicate in Q 3 state shifted to Q 1 state and the silicate chain became shorter, shifting from long-range, disordered to short-range, ordered. As the disordered self-seeding growth of long silicate chains derived from C-S-H continued, the Si-O-Si network of silica nanoparticles became chaotic, leaving more unreacted Si-OH on its surface. On the contrary, the short silicate chains displayed higher possibility of condensation, making nanoparticles with a smaller diameter.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Jiang-Hao Lu,Ze Li,Di Zhang,Lu-Hang Song,Xiao-Yan Cai,Liang Mao,Zhi-Qiang Liu,Zhi-Jie Wang,Xiu-Quan Gu,Guo-Dong Yuan
The nano/microstructuring of silicon (Si) via chemical methods has garnered significant attention due to its excellent light-trapping capabilities across a wide spectral range. Current research has predominantly focused on the synthesis of pyramidal-shaped microtextures, which enable two reflections on the surface, while largely overlooking the superior light-trapping potential of inverted pyramid silicon (SiIP) microtextures, which theoretically allow for three reflections. Moreover, there has been limited investigation into the application of inverted pyramid black silicon for solar-driven hydrogen evolution. This study reports the synthesis of uniformly arranged inverted pyramid-textured black silicon using the copper-assisted chemical etching (Cu-ACE) method to enhance the efficiency of solar-driven water splitting for hydrogen production. The formation mechanism and the influence of copper-localized surface plasmon resonance (Cu-LSPR) from Cu nanoparticle (NP) byproducts on photoelectrochemical (PEC) activity were systematically analyzed. To reduce sidewall defects and minimize photogenerated carrier recombination, the surface of the SiIP was treated with tetramethylammonium hydroxide (TMAH). A vertical PN junction was developed through ion implantation to reduce the external bias of the SiIP. Additionally, a uniform TiO₂ antireflective layer was deposited via atomic layer deposition (ALD), reducing the average reflectance of the SiIP-T 4 to 5.78 % over the 300–1100 nm wavelength range. MoSₓ and Pt NPs were electrodeposited to improve the fill factor and enhance HER kinetics. With optimized catalyst loading, the n + p-SiIP-T 4 /TiO₂/Pt 80 mC electrode achieved a photocurrent density of 8.0 mA cm −2 at 0 V vs. RHE, an applied bias photon-to-current efficiency (ABPE) of 0.93 % at 0.24 V vs. RHE, and a double-layer capacitance (Cdl) of 91 μF cm −2 . The onset potential (Von) was positively shifted by ∼1.13 V to 0.49 V vs. RHE compared to a SiIP photocathode, and the photocathode operated continuously at 0 V vs. RHE for 27 h in an acidic electrolyte. These results demonstrate that SiIP has significant potential for PEC hydrogen evolution, with further performance optimization achievable through structural and surface engineering.
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Small
·
2024
·Vol. 20
·期 37
·2401345
·
IF 13
Zhuoying Wu,Yongqun Ma,Siying Li,Liming Que,Hongbo Chen,Fei Hao,Xiaole Tao,Hao Xing,Jialin Ye,Dan Qian,Min Ling,Weiwei Zhu,Chengdu Liang
Novel binder designs are shown to be fruitful in improving the electrochemical performance of silicon (Si)-based anodes. However, issues with mechanical damage from dramatic volume change and poor lithium-ion (Li + ) diffusion kinetics in Si-based materials still need to be addressed. Herein, an aqueous self-repairing borate-type binder (SBG) with a web-like architecture and high ionic conductivity is designed for Si and SiO electrodes. The 3D web-like architecture of the SBG binder enables uniform stress distribution, while its self-repairing ability promotes effective stress dissipation and mechanical damage repair, thereby enhancing the damage tolerance of the electrode. The tetracoordinate boron ions ( − BO 4 − $ - {\mathrm{BO}}_4^ - $ ) in the SBG binder boosts the Li transportation kinetics of Si-based electrodes. Based on dynamic covalent and ionic conductive boronic ester bonds, the diverse requirements of the binder, including uniform stress distribution, self-repairing ability, and high ionic conductivity, can be met by simple components. Consequently, the proposed straightforward multifunction design strategy for binders based on dynamic boron chemistry provides valuable insights into fabricating high-performance Si-based anodes.
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Materials Today Chemistry
·
2025
·
IF 6.7
Kai Zhang,Wenying Zhou,Na Lin,Chenyu Li,Jinming Fan,Jiahuan Zhao,Yuan Jia,Mengxue Yuan
With the wide applications of polymer dielectrics in electronic devices and power supply systems, it is of great importance to explore polymeric composites with simultaneously high dielectric permittivity ( ε ) along with low loss ( tan δ ), and large breakdown strength ( E b ). To concurrently achieve these superior qualities in silicon (Si)/poly(vinylidene fluoride) (PVDF), in this study, a sol-gel method was used to decorate raw Si with a layer of titanium oxide (TiO 2 ), which was then incorporated into PVDF to produce a series of Si@TiO 2 /PVDF composites with diverse TiO 2 shell thicknesses. The findings demonstrate that compared with pristine Si/PVDF both loss and leakage conductivity of Si@TiO 2 /PVDF are markedly decreased by the TiO 2 shell, which enhances the interfacial compatibility between Si and PVDF, and blocks the creation of conductive network from virgin Si particles, inhibiting the long-range migration of carriers. Furthermore, the TiO 2 interlayer not only induces traps and increases the energy barrier height for trapped charges to de-trap, but also mitigates the intense interfacial dielectric mismatch subsequently lifting the E b . The theoretic fitting results via Havriliak-Negami equation demonstrate the TiO 2 shell’ suppression on charge migration and reveal the underlying polarization mechanism. Fine assembly of TiO 2 with desirable thickness onto Si realizes effective regulation of over dielectric parameters of the composites. The developed Si@TiO 2 /PVDF present concurrently high ε , E b but low loss characteristics, indicating promising potential applications in advanced electronic devices and power systems.
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Sustainable Materials and Technologies
·
2024
·
IF 8.6
Siyue Fu,Jianhua Zhou,Guojing Wu,Wenping Liu,Haiqing Qin,Chenyan Liu,Tomohiro Sato,Ying Peng,Lei Miao
The conceptual design of yolk-shell structured Si/C composite materials is considered an effective approach to enhancing the structural stability of silicon-based anode materials over long cycles. Here, for the first time, zinc oxide is used as both the internal sacrificial layer and the external coating layer reactant, allowing it to be transformed into voids and the carbon layer precursor during subsequent operations. These internal voids can buffer the volume expansion of silicon, ensuring the electrode's integrity during cycling. The ZIF layer formed through in-situ solvothermal reactions can effectively reduce the occurrence of isolated ZIF in the solvent, resulting in better coating of the nano‑silicon particles. Compared to traditional processes for preparing yolk-shell structures, this gentle synthesis strategy avoids the use of HF, offering a new direction for large-scale production. This optimized yolk-shell Si/C-0.70 M electrode exhibits excellent rate performance (specific capacity of 988 mA h g −1 at a high current density of 2 A g −1 ) and long-term cycling stability (specific capacity of 722 mA h g −1 after 300 cycles at a current density of 0.5 A g −1 ; reversible specific capacity of 557 mA h g −1 after 500 cycles). Therefore, this scalable study offers a new approach for safely producing yolk-shell anode materials with high cycle stability on a large scale.
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PROGRESS IN ORGANIC COATINGS
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2024
·
IF 6.5
Quan Yuan,Liwei Yan,Jinfeng Tian,Yang Chen,Huawei Zou
With the development of the new generation space vehicles, traditional phenolic resin (PR)-based coatings are no longer able to meet the increasingly harsh thermal environment. There is an urgent need to develop higher performance PR to ensure the flight safety of aircraft. Therefore, in this work, a novel hyperbranched polysiloxane containing Si-O-Zr bond was synthesized and then introduced into PR to develop homogeneous silicone/phenolic hybrid resin coatings. The TG results indicate that the introduction of Si-O-Zr bonds significantly improves the heat resistance of silicone. During ablation, the hyperbranched polysiloxane will undergo a ceramization to produce SiO 2 and ZrO 2 particles, both of which will subsequently generate a highly viscous Zr-Si-O glassy phase as anti-ablation layer. With the fluidity and self-healing properties, it can fill the gaps of the carbon layer and cover the surface of the carbon layer, giving the hybrid resin excellent ablative resistance. The linear ablation rate of the hybrid resin can be as low as 0.003 mm/s, which is an 80 % decrease compared to pure PR. The synthesized hybrid resin is expected to act as superior thermal protection coatings for the next generation of spaceflight.
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SENSORS AND ACTUATORS B-CHEMICAL
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2024
·
IF 8
Ying Li,Kang Liu,Xin Li,Xuan Jin,Jinze Lyu,Yuebing Xu,Haiyan Zhu,Gang Shi
It is difficult for metal-modified semiconductor nanotubes to obtain surface-enhanced Raman scattering (SERS) substrates through long-range ordered 3D assembly, which adversely affects both Raman signal enhancement and Raman signal uniformity. Here, ZnFe 2 O 4 nanotubes with Ag nanoparticles modified on the inner and outer walls are induced to grow on the surface of the ordered Si pyramid by ZnO nanonedles as sacrificial templates. In this way, the composite nanotubes (Ag/ZnFe 2 O 4 ) are assembled into dandelion flower-like 3D aggregates with a periodic arrangement of hexagonal close packing. This 3D ordered SERS substrate based on Ag/ZnFe 2 O 4 nanotubes has excellent anti-reflective performance and carrier separation ability, which is conducive to the enhancement of Raman signal. When the SERS substrate is used as a sensor, it can achieve the single molecule (10 −13 M) detection level of Rhodamine 6 G, the enhancement factor (EF) is 3.14 × 10 9 , and the linear fit (R 2 ) of quantitative analysis is as high as 0.998 from 10 −13 to 10 −4 M. Meanwhile, the long-range ordered arrays on the SERS substrate can ensure the signal uniformity of sensor, which relative standard deviation (RSD) is as low as 3.37 %. In addition, the photocatalytic self-cleaning capability of SERS substrate ensures that the sensor can be reused. Finally, the mechanism of the photogenerated carrier migration of Ag/ZnFe 2 O 4 and its contribution to Raman signal enhancement were analyzed.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yanming Wang,Ruijie Guo,Jie Zhang,Huifang Wang,Baolong Niu,Hong Yan
In general, the addition of flame retardants may lead to the degradation of the mechanical properties of polymers, despite enhancing their flame retardancy. However, flame-retardant coatings have the potential to provide good flame resistance to polymers without compromising their inherent mechanical properties. In this study, we applied highly adhesive and flexible polysiloxane flame-retardant coatings (196 μm) to polypropylene , resulting in reductions of 74.9 %, 58.0 %, 80.0 %, and 56.4 % in peak heat release rate , peak smoke production rate, fire growth rate, and mass loss, respectively. By incorporating the lab-synthesized DOPO-modified polysiloxane (APID), the flame-retardant efficiency of ammonium polyphosphate (APP) was greatly enhanced. The primary film-forming agent, (3-aminopropyl) triethoxysilane (APTES), played a key role in maintaining the compatibility of APP and APID with the coating, as well as facilitating the formation of a robust Si O Si crosslinked network structure that strengthened the resulting char layer. The interactivity between the various components, including hydrogen bonds and crosslinked network structures, contributed to improved uniformity, thermal stability, and adhesion of the coatings. Moreover, the coatings exhibited resistance to ultraviolet radiation and water. Our findings suggest that highly flexible and adhesive flame-retardant coatings hold significant potential for applications in polymer protection. These promising results provide a viable pathway for improving the fire protection of polymers through the use of high-adhesive intumescent flame-retardant coatings.
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International Journal of Applied Ceramic Technology
·
2018
·Vol. 15
·期 5
·1146-1156
·
IF 1.165
Qingliang Shan,Jianbao Hu,Yanmei Kan,Dewei Ni,Le Gao,Xiaowu Chen,Shaoming Dong
Si-B-C ceramics were prepared through reaction sintering, and the influence of Al 2 O 3 addition on the high-temperature (1100-1300°C) oxidation behavior of the material under air atmosphere was studied. The erosion behavior and mechanism are determined from the measurement of weigh changes, microstructure observations, and characterization of the generated oxides on postexposure specimens. Results show that Al 2 O 3 is enriched in the oxidized layer, inhibiting the volatilization of B 2 O 3 and impeding the crystallization ability of oxide (cristobalite). Narrower erosion layer and less weigh change are observed with Al 2 O 3 . Low-frequency Raman results reveals that with the increase in Al 2 O 3 , the bending vibrations of the BO 4 units and B-O-B stretching of the metaborate ring relative intensity are enhanced. Furthermore, high-frequency Raman results shows that the relative proportion of high-dimensional vibration modes Q 3 and Q 4 which result in a higher viscosity of melt and a greater resistance of oxygen diffusion are positively correlated with Al 2 O 3 .
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 35
·期 21
·1-13
·
IF 2.8
Su Congxue,Tao Wenlong,Chen Lianchun,Che Haiyan,Wang Ruijuan,Fan Jun,Qin Xingliu,Chen Zhilin,Fang Liang
Orthorhombic olivine-structured LiTmRO 4 (R = Si, Ge) ceramics were synthesized using a solid-state reaction. Promising microwave dielectric properties of ε r = 8.18, τ f = 13.7 ppm/°C and a high-quality factor ( Q × f ) of 24,274 GHz for LiTmSiO 4 were obtained at 1130 °C, and ε r = 8.67, τ f = − 24.4 ppm/°C and Q × f = 19,231 GHz for LiTmGeO 4 were achieved at 1090 °C. According to the bond valence results, Tm 3+ and Ge 4+ presented a compressed state, but Li + exhibited a strong rattling state in LiTmGeO 4 , which led to a higher ε r than ε theo . The integrated effect of the rattling cations (Li + and Si 4+ ) and a compressed cation (Tm 3+ ) in LiTmSiO 4 resulted in a smaller positive deviation ∆ ε r . The larger packing fraction of LiTmSiO 4 contributed to a higher Q × f than that of LiTmGeO 4 . The R–O bond in both ceramics played a leading role in influencing Q × f according to the Phillips–Van Vechten–Levine chemical bond theory.
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危险品化学品经营许可证（带存储）