Carbonitride MXenes,such as Ti_(3)CNT_(x),Ti_(2)C_(0.5)N_(0.5)T_(x),and Ti_(4)(C_(0.2)N_(0.8))_(3)T_(x),have attracted much interest in the large family of two-dimensional(2D)nanomaterials.Like their carbide MXene cou...Carbonitride MXenes,such as Ti_(3)CNT_(x),Ti_(2)C_(0.5)N_(0.5)T_(x),and Ti_(4)(C_(0.2)N_(0.8))_(3)T_(x),have attracted much interest in the large family of two-dimensional(2D)nanomaterials.Like their carbide MXene counterparts,the nanolayered structure and functional groups endow carbonitride MXenes with an attractive combination of physical and chemical properties.More interestingly,the replacement of C by N changes the lattice parameters and electron distribution of carbonitride MXenes due to the greater electronegativity of N as compared to C,thus resulting in significantly enhanced functional properties.This paper reviews the development of carbonitride MXenes,the preparation of 2D carbonitride MXenes,and the current understanding of the microstructure,electronic structure,and functional properties of carbonitride MXenes.In addition,applications,especially in energy storage,sensors,catalysts,electromagnetic wave shielding and absorption,fillers,and environmental and biomedical fields,are summarized.Finally,their current limitations and future opportunities are presented.展开更多
Changing the N content in the Ti_(3)AlC_(2−y)N_(y) MAX phase solid solutions allows for the fine-tuning of their properties.However,systematic studies on the synthesis and properties of Ti_(3)AlC_(2−y)N_(y) solid solu...Changing the N content in the Ti_(3)AlC_(2−y)N_(y) MAX phase solid solutions allows for the fine-tuning of their properties.However,systematic studies on the synthesis and properties of Ti_(3)AlC_(2−y)N_(y) solid solution bulks have not been reported thus far.Here,previously reported Ti_(3)AlC_(2−y)N_(y) solid solution bulks(y=0.3,0.5,0.8,and 1.0)were synthesized via hot pressing of their powder counterparts under optimized conditions.The prepared Ti_(3)AlC_(2−y)N_(y) bulks are dense and have a fine microstructure with grain sizes of 6–8μm.The influence of the N content on the mechanical properties,electrical conductivities,and coefficients of thermal expansion(CTEs)of the prepared Ti_(3)AlC_(2−y)N_(y) bulk materials was clarified.The flexural strength and Vickers hardness values increased with increasing N content,suggesting that solid solution strengthening effectively improved the mechanical properties of Ti_(3)AlC_(2−y)N_(y).Ti_(3)AlCN(y=1)had the highest Vickers hardness and flexural strength among the studied samples,reaching 5.54 GPa and 550 MPa,respectively.However,the electrical conductivity and CTEs of the Ti_(3)AlC_(2−y)N_(y) solid solutions decreased with increasing N content,from 8.93×10^(−6) to 7.69×10^(−6) K^(−1) and from 1.33×10^(6) to 0.95×10^(6) S/m,respectively.This work demonstrated the tunable properties of Ti_(3)AlC_(2−y)N_(y) solid solutions with varying N contents and widened the MAX phase family for fundamental studies and applications.展开更多
基金Fundamental Research Funds for the Central Universities,Grant/Award Numbers:2023YJS061,2023JBZY019。
文摘Carbonitride MXenes,such as Ti_(3)CNT_(x),Ti_(2)C_(0.5)N_(0.5)T_(x),and Ti_(4)(C_(0.2)N_(0.8))_(3)T_(x),have attracted much interest in the large family of two-dimensional(2D)nanomaterials.Like their carbide MXene counterparts,the nanolayered structure and functional groups endow carbonitride MXenes with an attractive combination of physical and chemical properties.More interestingly,the replacement of C by N changes the lattice parameters and electron distribution of carbonitride MXenes due to the greater electronegativity of N as compared to C,thus resulting in significantly enhanced functional properties.This paper reviews the development of carbonitride MXenes,the preparation of 2D carbonitride MXenes,and the current understanding of the microstructure,electronic structure,and functional properties of carbonitride MXenes.In addition,applications,especially in energy storage,sensors,catalysts,electromagnetic wave shielding and absorption,fillers,and environmental and biomedical fields,are summarized.Finally,their current limitations and future opportunities are presented.
基金supported by the Fundamental Research Funds for the Central Universities(Nos.2023YJS061 and 2023JBZY019).
文摘Changing the N content in the Ti_(3)AlC_(2−y)N_(y) MAX phase solid solutions allows for the fine-tuning of their properties.However,systematic studies on the synthesis and properties of Ti_(3)AlC_(2−y)N_(y) solid solution bulks have not been reported thus far.Here,previously reported Ti_(3)AlC_(2−y)N_(y) solid solution bulks(y=0.3,0.5,0.8,and 1.0)were synthesized via hot pressing of their powder counterparts under optimized conditions.The prepared Ti_(3)AlC_(2−y)N_(y) bulks are dense and have a fine microstructure with grain sizes of 6–8μm.The influence of the N content on the mechanical properties,electrical conductivities,and coefficients of thermal expansion(CTEs)of the prepared Ti_(3)AlC_(2−y)N_(y) bulk materials was clarified.The flexural strength and Vickers hardness values increased with increasing N content,suggesting that solid solution strengthening effectively improved the mechanical properties of Ti_(3)AlC_(2−y)N_(y).Ti_(3)AlCN(y=1)had the highest Vickers hardness and flexural strength among the studied samples,reaching 5.54 GPa and 550 MPa,respectively.However,the electrical conductivity and CTEs of the Ti_(3)AlC_(2−y)N_(y) solid solutions decreased with increasing N content,from 8.93×10^(−6) to 7.69×10^(−6) K^(−1) and from 1.33×10^(6) to 0.95×10^(6) S/m,respectively.This work demonstrated the tunable properties of Ti_(3)AlC_(2−y)N_(y) solid solutions with varying N contents and widened the MAX phase family for fundamental studies and applications.
