二维氮化碳(C_xN_y)材料的结构、性质及应用研究进展

Two-dimensional carbon nitride (C_xN_y) materials have emerged as highly promising 2D low-dimensional materials due to their highly tunable atomic structure and exceptional physicochemical properties. With their diverse structural variants and rich nitrogen chemical characteristics, these materials offer a unique platform for exploring novel quantum phenomena, customizing band structures, and achieving multifunctional properties. This review presents an innovative and comprehensive “structure-performance-application” framework for nitrogen type correlation, systematically revealing the evolution of C_xN_y materials from atomic-scale structure to macroscopic properties, and closely linking theoretical and experimental research. It provides an in-depth discussion of the multifunctional properties of C_xN_y materials, including stability, tunable electronic band structure, electrochemical activity, spectral response, and catalytic performance. Based on structure-property relationships, the review analyzes their potential applications in energy storage and conversion (e.g., lithium-ion batteries, supercapacitors), environmental remediation (e.g., photocatalysis, CO₂ reduction), electronic devices, and sensing, while establishing quantitative predictive models for performance and structural parameters. Firstly, the review introduces the regulation mechanisms of various nitrogen types, such as pyridinic nitrogen, graphitic nitrogen, and pyrrolic nitrogen, on electronic structure and chemical bonding. Based on the differences in nitrogen atomic coordination environments, C_xN_y materials are briefly classified into four main categories: graphitic nitrogen type, pyridinic nitrogen type, coexistence of graphitic and pyridinic nitrogen types, and other nitrogen types. The structural forms composed of different coordination types for each of the four categories of C_xN_y materials are then discussed in detail. Next, a systematic summary of the various properties of two-dimensional C_xN_y materials is provided, along with an overview of their corresponding applications. In terms of stability, the theoretical foundation of the thermodynamic, kinetic, chemical, and mechanical stability of C_xN_y materials is explained through density functional theory calculations and experimental verification, highlighting the role of nitrogen types in regulating the stability of two-dimensional C_xN_y materials. Regarding electronic properties, a comprehensive analysis is presented on the band structure, band gap characteristics, electrical conductivity, carrier mobility, and charge distribution of two-dimensional C_xN_y materials. The structure-property relationships between the C/N ratio and the band gap, as well as between nitrogen types and the band gap, are summarized. In the domain of electrochemical properties, the review outlines the regulatory mechanisms of nitrogen type and nitrogen content on the ion diffusion kinetics, theoretical ion capacity, and ion battery voltage of two-dimensional C_xN_y materials. For optical properties, the dependence of light absorption and light response in the ultraviolet-visible-infrared spectral range on composition and structure is systematically discussed. The relationship between optical properties of two-dimensional C_xN_y materials and nitrogen atomic types is also summarized. Specifically, the type and ratio of nitrogen atoms directly determine the material’s band gap width and optical response range. As nitrogen content and coordination types vary, the band gap of the material can be adjusted from wide to narrow, and the light absorption range can extend from the ultraviolet to the visible region. In terms of catalytic properties, the review elaborates on how nitrogen types, coordination environments, and doping influence the catalytic performance of two-dimensional C_xN_y materials. Additionally, other properties and application scenarios of two-dimensional C_xN_y materials are introduced, including molecular adsorption and filtration, environmental monitoring and sensing, pollutant degradation, wearable devices, and biomedical applications. Finally, the challenges and future prospects for the development of two-dimensional C_xN_y materials are outlined. Future directions are proposed to address issues such as controllable synthesis, scalable production, defect regulation mechanisms, theory-experiment synergy, and multi-scale modeling: developing precise synthesis techniques, constructing multi-scale theoretical models, exploring multi-dimensional optimization strategies, and advancing engineering applications. Through systematic theoretical analysis and forward-looking perspectives, this review aims to provide comprehensive scientific guidance for the fundamental research and application development of C_xN_y materials, promoting the field’s advancement towards higher performance and industrialization.