# Two-Dimensional Metal-Organic Frameworks and Their Derivative Electrocatalysts for Water Splitting
## 4 Summary and Outlook  
In conclusion, this study provides a comprehensive review of various synthesis methods employed in the preparation of 2D MOFs and their derivatives, with a specific focus on their applications in electrocatalytic hydrolysis. Despite significant advancements made in recent years, 2D MOFs and their derivatives in electrocatalysis continue to be an intriguing research area that is anticipated to attract increased attention. On the whole, 2D MOFs and their derivatives are emerging as particularly promising electrocatalysts due to several distinguishing properties. Primarily, the unique structure of 2D MOFs affords them efficient ion transport and electron transfer capabilities. In addition, 2D MOFs possess a vast active surface area and myriad active sites, facilitating the absorption of hydrogen ions. Furthermore, the selectable nature of metal ions and ligands presents a plethora of potential structural combinations, allowing for the design and synthesis of 2D MOFs with controllable morphology. The introduction of varied functional groups via different ligands can also enhance catalytic performance in diverse ways, thereby adding another layer of versatility to these advanced materials. This review highlights several opportunities and challenges associated with MOFs and their derivatives in electrocatalysis and provides outlook and perspectives for future research:  
(1) Both top-down and bottom-up synthesis methods come with their inherent drawbacks. While the top-down approach offers simplicity, it is often marred by inconsistent results and a low yield. Conversely, the bottom-up synthesis method may be influenced by solvents and other added materials during the synthesis process. Identifying and overcoming these limitations, as well as finding ways to mitigate adverse effects on 2D MOF materials, will play a pivotal role in enhancing their performance. (2) 2D MOFs, with their rich porosity, tunable structures, and high specific surface areas, hold promise in enhancing catalytic performance. However, their low conductivity and stability need to be addressed. Therefore, there is a need to develop more stable and conductive 2D MOF materials. Exploring the change in electronic configuration between the ligand and the central atom in 2D MOFs can provide insights for designing structures with higher electron transfer rates and improved stability. (3) The substantial cost of certain organic ligands used in the synthesis of 2D MOFs presents a significant obstacle to their broad application. The development of cost-effective ligands is of utmost importance for the design of efficient 2D MOF catalysts that are suitable for practical usage. (4) Despite the superior benefits that 2D MOF derivatives bring compared to 2D MOFs, complications such as the collapse of porous structures and agglomeration of metal particles during the carbonization process can notably compromise their performance. Therefore, a heightened focus on the detailed changes that occur during the carbonization process and the development of more efficient synthesis methods to maintain the desirable attributes is imperative. (5) Organic ligands encompass a wide variety of functional groups, each with different electron-donating abilities and potential contributions to the catalytic performance and stability of 2D MOFs after coordination. Furthermore, some organic ligands featuring specific functional groups have the capability to bind with hydrogen ions. This characteristic facilitates their absorption of hydrogen ions from aqueous solutions, making it easier for the ions to transfer to metal ions at active sites. This process inherently enhances the performance of the catalysts. However, there is limited research in this area. Exploring 2D MOFs and their composites with different functional groups holds considerable potential for tailoring their properties and enhancing their catalytic performance and stability.