Advanced Powder Materials最新文献

Nanozymes, a category of nanomaterials endowed with enzyme-mimicking capabilities, have exhibited considerable potential across diverse application domains. This comprehensive review delves into the intricacies of regulating nanozymes through N elements, elucidating the mechanisms governing N element control in the design and application of these nanomaterials. The initial sections introduce the foundational background and significance of nanozymes. Subsequent exploration delves into the detailed discussion of N element regulation mechanisms on nanozymes, encompassing N vacancies, N doping, N coordination, and nitride. These regulatory pathways play an instrumental role in fine-tuning the catalytic activity and specificity of nanozymes. The review further scrutinizes practical applications of N element regulation on nanozymes, spanning sensing detection, infection therapy, tumor therapy, and pollutant degradation. In conclusion, it succinctly summarizes the current research findings and proposes future directions for development. This thorough investigation into the regulation of nanozymes by N elements anticipates precise control over their performance, thereby advancing the extensive utilization of nanozymes in the realms of biomedical and environmental applications.

CO₂ reduction by CH₄ (CRM) to produce fuel is of great significance for solar energy storage and eliminating greenhouse gas. Herein, the catalyst of ultrafine Ni nanoparticles supported on CeZrNiO₂ solid solution (Ni@CZNO) was synthesized by the sol-gel method. High yield of H₂ and CO (58.0 and 69.8 ​mmol ​min⁻¹ ​g⁻¹) and excellent durability (50 ​h) were achieved by photothermal catalytic CRM merely under focused light irradiation. Structural characterization and DFT calculations reveal that CZNO has rich oxygen vacancies that can adsorb and activate CO₂ to produce reactive oxygen species. Oxygen species are transferred to ultrafine Ni nanoparticles through the rich Ni-CZNO interface to accelerate carbon oxidation, thereby maintaining the excellent catalytic stability of the catalyst. Moreover, the experimental results reveal that light irradiation can not only enhance the photothermal catalytic CRM activity through photothermal conversion and molecular activation, but also improve the stability by increasing the concentration of oxygen vacancies and inhibiting CO disproportionation.

Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic, while understanding the ablation mechanism is the foundation. Here, through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide, Nb-rich carbide, and Zr-rich silicide phases, we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation. It was found that this solid-state reaction occurred in the matrix/oxide scale interface region. In this process, metal cations are counter-diffused between the multicomponent phases, thereby resulting in their composition evolution, which allows the multicomponent phases to exist stably under a higher oxygen partial pressure, leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic. Additionally, this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.

Reversible protonic ceramic electrochemical cells (R-PCECs) demonstrate great feasibility for efficient energy storage and conversion. One critical challenge for the development of R-PCECs is the design of novel air electrodes with the characteristics of high catalytic activity and acceptable durability. Here, we report a donor doping of Hf into the B-site of a cobalt-based double perovskite with a nominal formula of PrBa_0.8Ca_0.2Co_1.9Hf_0.1O_5+δ (PBCCHf_0.1), which is naturally reconfigured to a double perovskite PrBa_0.8-xCa_0.2Co_1.9Hf_0.1-xO_5+δ (PBCCHf_0.1-x) backbone and nano-sized BaHfO₃ (BHO) on the surface of PBCCHf_0.1−x. The air electrode demonstrates enhanced catalytic activity and durability (a stable polarization resistance of 0.269 ​Ω ​cm² for ∼100 ​h at 600 ​°C), due likely to the fast surface exchange process and bulk diffusion process. When employed as an air electrode of R-PCECs, a cell with PBCCHf_0.1 air electrode demonstrates encouraging performances in modes of the fuel cell (FC) and electrolysis (EL) at 600 ​°C: a peak power density of 0.998 ​W ​cm⁻² and a current density of −1.613 ​A ​cm⁻² ​at 1.3 ​V (with acceptable Faradaic efficiencies). More importantly, the single-cell with PBCCHf_0.1 air electrode demonstrates good cycling stability, switching back and forth from FC mode to EL mode ±0.5 ​A ​cm⁻² for 200 ​h and 50 cycles.

Cr³⁺-activated near-infrared (NIR) phosphors are key for NIR phosphor-converted light emitting diodes (NIR pc-LED). While, the site occupancy of Cr³⁺ is one of the debates that have plagued researchers. Herein, Y₂Mg₂Al₂Si₂O₁₂ (YMAS) with multiple cationic sites is chosen as host of Cr³⁺ to synthesize YMAS: xCr³⁺ phosphors. In YMAS, Cr³⁺ ions occupy simultaneously Al/SiO₄ tetrahedral, Mg/AlO₆ octahedral, and Y/MgO₈ dodecahedral sites which form three luminescent centers named as Cr1, Cr2, and Cr3, respectively. Cr1 and Cr2 relate to an intermediate crystal field, with transitions of ²E→⁴A₂ and ⁴T₂→⁴A₂ occurring simultaneously. As Cr³⁺ concentration increases, the ⁴T₂→⁴A₂ transition becomes more pronounced in Cr1 and Cr2, resulting in a red-shift and broadband emission. Cr3 consistently behaves a weak crystal field and exhibits the broad and long-wavelength emission. Wide-range NIR emission centering at 745 ​nm is realized in YMAS: 0.03Cr³⁺ phosphor. This phosphor has high internal quantum efficiency (IQE ​= ​86%) and satisfying luminescence thermal stability (I_{423 K} ​= ​70.2%). Using this phosphor, NIR pc-LEDs with 56.6 ​mW@320 ​mA optical output power is packaged and applied. Present study not only demonstrates the Cr³⁺ multi-site occupancy in a certain oxide but also provides a reliable approach via choosing a host with diverse cationic sites and local environments for Cr³⁺ to achieve broadband NIR phosphors.

Microstructural design and processing science of ceramics from materials to devices are critical to the present and future applications in various fields. They have profound effects on the mechanical and functional properties, as well as the reliability and lifetime of ceramics. The stability issue has been attracting more and more attentions, as many devices are pushed towards extreme service conditions to gain additional benefits such as energy density and efficiency. In this pespective article, we shall discuss on four selected topics of energy ceramic design, including the oxygen evolution issue of oxide battery cathodes under extreme charge voltages, the synthesis conundrum of single-crystalline battery cathodes, the metal/ceramic interface contact problem in all-solid-state lithium-metal batteries, and the nature of hole polarons in oxygen ion and protonic ceramic electrolytes. Our understanding and solutions to these challenging problems shall be discussed. The new fundamental insights and rationally optimized processing practices presented here could help to develop advanced interdisciplinary ceramics further, enabling exciting applications in the coming decades.

All-solid-state sodium (Na)-metal batteries (ASSSMBs) are considered promising candidates for large-scale energy storage systems due to their abundant sodium resources, unparalleled safety performance, and impressive energy density. Na superionic conductors (NASICONs) are among the best enablers of ASSSMBs in view of their high ionic conductivity, ease of synthesis, and excellent thermal stability and good electrochemical/chemical compatibility with common electrodes. However, challenges surrounding the NASICON/electrode interface, such as high interfacial resistance and dendrite formation, have hindered the development of practical ASSSMBs based on NASICONs. This review starts with an explicit summary of the interface problems between the metallic Na anode and NASICON arising from mechanical, chemical, and electrochemical aspects (i.e., poor interface contact, insulating side-reaction products, and irregular dendrite growth). Subsequently, we systematically analyze and logically categorize modification strategies for addressing anode interface problems and provide a comprehensive discussion on the underlying enhancement mechanisms. As such, we identify underlying and universal interface enhancement mechanisms by comparatively studying various modification strategies. Furthermore, we briefly summarize the challenges in the cathode/electrolyte interface and early-stage research efforts in constructing stable cathode/electrolyte interface and fabricating high-performance composite cathodes. Finally, key suggestions and future prospectives for the advancement of NASICON-based ASSSMBs are outlined.

High pressure technology has been utilized as an important means to regulate phase structure and improve the properties/performance of alloys. The CALPHAD approach based on accurate databases has great advantages in efficient alloy design. However, the application of CALPHAD in high pressure field is hindered by the lack of reliable thermodynamic model/database for multicomponent alloys under pressure. In this paper, a phenomenologically thermodynamic model for multicomponent alloys under pressure is first developed by separating the contribution into two parts, one is at atmosphere pressure and the other is caused by an increase in pressure, and then successfully applied to establish the pressure-dependent thermodynamic database of ternary Al–Si–Mg system. The calculated phase equilibria/thermodynamic properties of pressure dependence in related alloys are in good agreement with the limited experimental data in the literature, validating the reliability of the obtained thermodynamic database. After that, a CALPHAD design framework for pressurized solidified alloys is proposed by integrating the present pressure-dependent thermodynamic model/database, CALPHAD-type calculations/simulations, and previously developed high-throughput calculation platform Malac-Distmas. Such a framework is finally applied to predict the pressurized solidification and high pressure heat treatment behaviors in different Al–Si–Mg alloys. The predicted microstructure, phase transitions and phase equilibria after pressurized solidification and high pressure heat treatment are consistent with the experimental data. Furthermore, the insights into effect of pressure on the thermodynamic essence of alloys are gained, which may definitely facilitate the advancement of alloy design under high pressure technology.

Understanding the evolution of the solid electrolyte-electrode interface is currently one of the most challenging obstacles in the development of solid-state batteries (SSBs). Here, we develop an X-ray Photoelectron Spectroscopy (XPS) that allows for operando measurement during cycling. Based on theoretical analysis and the modulated electrode and detector co-grounding mode, the displacement of binding energy can be correlated with the surface electrostatic potential of the material, revealing the charge distribution and composition evolution of the space charge layer between the cathode and the electrolyte. In the investigation of typical LiCoO₂ (LCO)/Li₆PS₅Cl (LPSC)/Li–In batteries, we observed the static potential difference and oxidative decomposition between LPSC and LCO, and the effectiveness of the LiNbO₃ coating in reducing potential difference and inhibiting the diffusion of Co and oxidation of S species. Furthermore, our study also revealed that the potential drop between LiNi_0·8Co_0·1Mn_0·1O₂ and LPSC is smaller than that of LCO, whilst that between Li₃InCl₆ and LCO remains near zero. The proposed operando XPS method offers a novel approach for real-time monitoring of interface potential and species formation, providing rational guidance for the interface engineering in SSBs.

Devising exceptional S-scheme heterojunction photocatalysts utilized in annihilating pharmaceuticals and chromium contamination is significant for addressing the problem of global water pollution. In this work, a chemically bonded Mn_0.5Cd_0.5S/BiOBr S-scheme heterostructure with oxygen vacancies is ingeniously developed through a facile in-situ solvothermal synthesis. The designed Mn_0.5Cd_0.5S/BiOBr heterojunction exhibits eminently reinforced photo-activity for destruction of tetracycline hydrochloride and Cr(VI) as compared with its individual components. This substantial photo-redox performance amelioration is benefitted from the creation of an intense internal electric field (IEF) via supplying powerful driving force and migration highway by interfacial chemical bond to foster the S-scheme electron/hole disintegration. More intriguingly, the IEF at the hetero-interface drives the fast consumption of the photo-induced holes in Mn_0.5Cd_0.5S by the photoelectrons from BiOBr, profoundly boosting the enrichment of active photo-carriers and sparing the photo-corrosion of Mn_0.5Cd_0.5S. Furthermore, Mn_0.5Cd_0.5S/BiOBr with exceptional anti-interference property can work efficiently in real water matrices. Multiple uses of the recycled Mn_0·5Cd_0·5S/BiOBr evidence its prominent robustness and stability. This achievement indicates the vast potential of chemically bonded S-scheme photosystems with structural defects in the design of photo-responsive materials for effective wastewater treatment.