Resources Chemicals and Materials最新文献

Carbon dioxide (CO₂) is one of the main factors contributing to the greenhouse effect. The dependence on fossil fuels has led to increasing levels of carbon dioxide in the atmosphere every year. And it is far from enough to solve the climate problem by reducing the consumption of fossil fuels to cut down carbon dioxide emissions. In recent years, a series of researches on Carbon Capture, Utilization and Storage (CCUS) have been carried out in various countries around the world. CO₂ is a nontoxic, tasteless and stable gas at normal temperature. However, when it reaches supercritical state after rising temperature and pressure, it has the characteristics of low viscosity, high diffusivity and high density, and is widely used in green, pollution-free and efficient development technology. Because of these unique properties, supercritical carbon dioxide (sCO₂) has attracted more and more attention from researchers. sCO₂ has been widely used in many aspects by virtue of its high solubility and easy compression. Different from previous reviews which only introduced the application of sCO₂ property, this paper introduces the current research status of the application of the thermodynamic property of carbon dioxide in extraction, dyeing, pharmaceutical, power generation, heat transfer and exploitation of unconventional oil and gas, and mainly analyzes each application in detail from the aspects of working mechanism and improving working efficiency. Finally, the research direction and problems needed to be solved for the application of CO₂ thermal physics are proposed, which pave the way for other new applications.

Benzyl benzoate (BB), an important ester, still demands for green synthesis routes. In this work, by size regulation and proper functionalization of carbon nanotubes (CNTs) as the support of gold catalyst, this ester can be synthesized very efficiently directly from benzyl alcohol via oxidative coupling. More attractively, the reaction is performed using water as green solvent and molecular oxygen as green oxidant. Simultaneously, very high selectivity to BB can be obtained near full conversion within very short reaction time (just 0.5 h), while the low-value benzoic acid byproduct is negligible. This is very different from many reported gold catalysts that yield much benzoic acid and/or benzaldehyde in water. The results show that, besides the size of CNTs (length and diameter), the functionalization of CNTs is also critical for improving both conversion and the selectivity to BB. In addition, the reaction mechanism for forming BB ester is put forward as well.

Biomass valorization by photoreforming approach provides a promising and alternative strategy to generate value-added chemicals and fuels. In this work, we demonstrate the selective production of lactic acid from glucose photoreforming over pristine graphitic carbon nitride (g-C₃N₄) photocatalyst. Control experiments screen the best condition for the highest yield of lactic acid, including modulating pH, catalyst loading, and reaction time. 100% glucose conversion is achieved along with almost 100% lactic acid yield under the optimized condition. Density functional theory (DFT) calculations reveal that the rate-determining step (RDS) of the overall reaction on g-C₃N₄ is the conversion of pyruvaldehyde, where an electron transfer takes place. This present work provides experimental insights and theoretical understanding for selective lactic acid production from biomass photoreforming.

A novel poly(ether block amide) (PEBA) based solid-state polymer electrolyte (SPE) was prepared using a casting method, in which 20wt% lithium (Li) bis-(trifluoromethanesulfonyl)imide (LiTFSI) and aluminum oxide (Al₂O₃) nanoparticles were used as the Li salt and solid plasticizer, respectively. In the case of addition of 3wt% Al₂O₃ nanoparticles, ion conductivity of the obtained PEBA 2533–20wt% LiTFSI-3wt% Al₂O₃ SPE was 3.57 × 10⁻⁵ S cm⁻¹ at 25 °C. Furthermore, the Li symmetrical battery assembled with it showed excellent cycling stability (1000 h) at 0.1 mA cm⁻². While, the assembled all-solid-state Li/PEBA 2533–20% LiTFSI-3wt% Al₂O₃/LiFePO₄ (areal capacity: 0.15 mAh cm⁻²) battery maintained 94.9% of the maximal capacity (133.9 mAh g^{−[email protected]} mA cm⁻²) at 60 °C even after 650 cycles with a superior average coulombic efficiency (CE) of 99.84%. By using X-ray photoelectron spectroscope (XPS), self-aggregation layer (SAL) of polyamide 12 (PA12) of PEBA 2533 was discovered, which should contribute to promoting the robustness of lithium fluoride (LiF) enriched solid-electrolyte interphase (SEI) layer. In addition, it is considered that the state of interface between SPE and cathode should be the cause of voltage polarization of the full cell.

Amine modification is an effective strategy to improve the H₂S removal performance of Cu-BTC. In order to avoid the problem of pore blockage after amine modification in post synthesis impregnation, herein a series of Cu-BTC modified with organic amine adsorbents were prepared via an in-situ one-pot method and the H₂S removal performance under ambient conditions was tested. It is found that the introduced organic amines, depending on the types of amine selected, have a significant influence on the growth of Cu-BTC and its textural properties. The H₂S removal performance on the as-prepared materials suggested that the amine modified samples remarkably improved the H₂S removal capacities with an order of BA-Cu-BTC > TEA-Cu-BTC > TEOA-Cu-BTC > Cu-BTC. Besides the enlarged surface area and the increased mesopores volumes, BA has the advantages of smaller steric hindrance and –NH₂ groups, among which the former increased the accessibility of Cu active sites while the latter acted as additional active sites for H₂S capturing, thus affording BA-Cu-BTC highest breakthrough capacity of 77.3 mg S/g. Overall, this study elaborates the effect of organic amines in-situ modification on the Cu-BTC structure and desulfurization.

As advanced functional materials, piezoelectric ceramics are widely used in various fields, including the medical, aviation, and military industries. With the advancement of science and technology, the piezoelectric ceramics needed in special fields have become more intelligent, diverse and lightweight. The shapes and structures of piezoelectric ceramics are becoming more complex. Traditional piezoelectric ceramic preparation technology has been unable to meet the high-speed and complex production demands of various industries. Considering this situation, 3D printing technology has attracted much attention in the field of piezoelectric ceramics. In this paper, the applications of several main 3D printing techniques in the field of piezoelectric ceramics are mainly introduced, and their development statuses, process characteristics and achievements are summarized. The advantages and disadvantages of each printing technique are summarized and compared. The challenges and possible future trends of 3D printing when manufacturing piezoelectric ceramics are summarized and proposed.

Wrought magnesium alloys with high-strength and high-ductility property have been attracting more and more interest in automotive and aerospace industries, and the conventional Mg-Zn based alloys are widely accepted as the representative one. Development of Mg-Zn based alloys with rare earth (RE) element additions and with modified preparation processes domains the evolution of their potential structural applications. Nonetheless, their highest tensile yield strength (TYS) is still in the order of 400 MPa, clearly lower than that of the Mg-RE based alloys, in the order of 500 MPa, much less compared with the high-strength aluminum alloys and titanium alloys. According to many previous investigations, two relatively efficient methods to improve mechanical properties of ZK based alloys were revealed as: alloying by RE and optimizing wrought processes. However, comprehensive combinative investigation was hitherto not conducted to date. Thus, it is imperative in the next work to further improve the yield strength to the order of 500 MPa or much higher, and simultaneously modify the tension-compression strength asymmetry of the ZK series alloys. Maybe, developing novel wrought processes for ZK60 (+ RE) alloys or exploring appropriate pre-dealing treatments before or after the wrought processes might be an important approach to accomplish a much higher level of balance of high-strength and high-ductility.

In order to resolve the global crisis of fossil energy shortage and climate warming, the development of efficient energy storage devices is a significant topic at present. Supercapacitors as the novel type of energy storage devices have the unique advantages, including the fast charging/discharging behaviors, high-energy/power density, and stable cycling performance. Compared with traditional supercapacitors, flexible supercapacitors are environmentally friendly, light weight, small size and high safety. Therefore, flexible supercapacitors have a wide application prospect in emerging electronic devices. Due to its flexibility, biocompatibility, and structure designability, cellulose and its gel materials are gradually used as electrodes, separators and electrolytes in flexible supercapacitors. Several construction processes at molecular scale for high-performance cellulose gels are summarized. Meanwhile, this review covers the recent progress of developing the flexible supercapacitors and all-in-one supercapacitors based on cellulose functional gels. We finally discussed the potential challenges and opportunities for cellulose and its derived materials in new-style flexible supercapacitors and other electronic devices.

Graphene films (GFs) featured with exceptional electrical property and macroscopic ultrathin two-dimensional structure demonstrate infinite potentials for electromagnetic interference shielding applications. By retrospecting the advanced achievements of GF-type shielding materials over the past decades, this review aims to provide a roadmap driven by the great progress and inspire future disruptive innovations. The fabrication methods of GFs are systematically discussed, with a particular emphasis on creative approaches. Strategies to optimize the shielding performance are elaborated in terms of manufacturing methods, shielding efficiency and properties, corresponding mechanisms, challenges and perspectives. Likewise, advancements of multifunctional GFs simultaneously satisfying electromagnetic shielding with thermal dissipation or transparent requirements are outlined. Using history as a mirror, a clear insight into this rapidly growing field is given, and corresponding current challenges and future opportunities in the fabrication and application of GF-family shielding materials are highlighted and envisioned. We hope this review can encourage further innovations in this exciting branch of research and inspire scientists from both academia and industry to promote revolutionary breakthroughs in GF-shields for next-generation shielding applications.