by molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 ), boron nitride (BN), and part of alloy nanosheets are two-element 2D materials; and transition metal carbide and nitride (MXene) are multielement 2D materials. [6][7][8][9] Graphene is widely used in catalysis due to its unique electronic structure. Its main applications include electrocatalysis, [10,11] photocatalysis, [12] and thermocatalysis. [13] Due to the lack of sufficient energy gap in natural graphene, the electron transfer efficiency is very low. [14] There are many ways to improve the catalytic performance of graphene, such as dislocations, vacancies, edges, impurities, and functional groups that interfere with the graphene structure. [6,15] Due to its unique physicochemical properties and broad application prospects, 2D element metal nanosheets (such as Ru, Bi, Rh, Pd, and Cu) have gradually attracted the attention of researchers. [16][17][18][19][20] The thickness of a single metal atom or several metal atoms makes them have ultrahigh specific surface area and relatively high surface energy, and the abundant surface metal active sites make them have a wide range of applications in the field of catalysis. For example, Ru NSs and their derived Ru oxides exhibit excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities, respectively. [16] Bi (001) porous nanosheets exhibit excellent electrochemical performance in the reduction of CO 2 to formate. [17] Single-crystal Rh nanosheets exhibit extremely high catalytic activity in hydrogenation reactions. [18] On this basis, 2D alloy nanosheets (such as PdAg, PdAu, AuAg, PtCu, etc.) have made substantial progress in the field of catalysis in recent years. [18] Compared with 2D element metal nanosheets, 2D alloy nanosheets not only inherit the advantages of ultrahigh specific surface area and inherent properties of 2D metals, but also the synergistic effect between different elements also promotes some catalytic reactions to a certain extent. TMDCs are widely used in heterogeneous catalysis due to their unique mechanical structure and electronic properties. The layered structure of TMDCs gives them highly anisotropic properties, extremely high specific surface area, the possibility of intercalating different species between the layers, and stability as ultrathin as thin as three atomic layers thick. [21] Structural cutting, defect engineering, chemical modification, and combination with other layered materials with complementary functions can effectively improve the catalytic activity of TMDCs. [22] For example, electrochemical tests on MoS 2 triangular clustersThe unique structure and properties of graphene make it have excellent performance in the field of catalysis. It can be modified in various ways to improve its catalytic ability. Notably, other 2D materials with similar properties to graphene (black phosphorus (BP), 2D transition metal dichalcogenides represented by molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 ), boron nitride (BN), and transiti...