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Open Access Research Article Issue
Self-assembled Ag4V2O7/Ag3VO4 Z-scheme heterojunction by pH adjustment with efficient photocatalytic performance
Journal of Advanced Ceramics 2022, 11 (11): 1789-1800
Published: 05 November 2022
Downloads:98

Semiconductor heterojunction plays a pivotal role in photocatalysis. However, the construction of a heterojunction with a fine microstructure usually requires complex synthetic procedures. Herein, a pH-adjusted one-step method was employed to controllably synthesize Ag4V2O7/Ag3VO4 heterojunction with a well-tuned 0D/1D hierarchical structure for the first time. It is noteworthy that the ordered stacking of vanadium oxide tetrahedron ( VO3) guided by the pH value wisely realizes the in-situ growth of Ag4V2O7 nanoparticles on the surface of Ag3VO4 nanorods. Furthermore, comprehensive characterization and calculation decipher the electronic structures of Ag4V2O7 and Ag3VO4 and the formation of Z-scheme heterojunction, benefiting the visible light harvesting and carrier utilization. Such a new Ag4V2O7/Ag3VO4 heterojunction exhibits remarkable photocatalytic activity and excellent stability. Complete degradation of Rhodamine B (RhB) can be achieved in 10 min by the Ag4V2O7/ Ag3VO4 heterojunction under visible light irradiation, demonstrating an outstanding reaction rate of 0.35 min−1 that is up to 84-fold higher than those of other silver vanadates. More importantly, this integration of synthesis technology and heterojunction design, based on the intrinsic crystal and electronic structures, could be inspiring for developing novel heterostructured materials with advanced performance.

Open Access Review Issue
Progress in ceramic materials and structure design toward advanced thermal barrier coatings
Journal of Advanced Ceramics 2022, 11 (7): 985-1068
Published: 02 July 2022
Downloads:578

Thermal barrier coatings (TBCs) can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat. However, the continuous pursuit of a higher operating temperature leads to degradation, delamination, and premature failure of the top coat. Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems. In this paper, the latest progress of some new ceramic materials is first reviewed. Then, a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth, ceramic sintering, erosion, and calcium-magnesium-aluminium-silicate (CMAS) molten salt corrosion. Finally, new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar, columnar, and nanostructure inclusions. The latest developments of ceramic top coat will be presented in terms of material selection, structural design, and failure mechanism, and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance, better thermal insulation, and longer lifetime.

Open Access Research Article Issue
High performance of La-doped Y2O3 transparent ceramics
Journal of Advanced Ceramics 2020, 9 (4): 493-502
Published: 18 June 2020
Downloads:46

As an optical material, Y2O3 transparent ceramics are desirable for application as laser host materials. However, it is difficult to sinter and dense of Y2O3 hinders the preparation of high-quality optical ceramics via traditional processes. In this work, we use La2O3 as a sintering aid for fabricating high-transparency Y2O3 ceramics using a vacuum sintering process. It is demonstrated that the in-line optical transmittance of 15.0 at% La-doped Y2O3 at a wavelength of 1100 nm achieves a transmittance of 81.2%. A sintering kinetics analysis reveals that a grain-boundary-diffusion-controlled mechanism dominates the faster densification at high La3+ concentrations. It is also shown that both the mechanical and thermal properties of Y2O3 transparent ceramics are significantly improved upon the increase of La2O3 sintering additives. The results indicate that a La-doped Y2O3 transparent ceramic is a promising candidate for a laser host material.

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