Metal-organic frameworks and their derivatives-modified photoelectrodes for photoelectrochemical applications

Artificial photosynthesis based on photoelectrochemical (PEC) strategy is another solar-to-chemical energy conversion method besides photocatalysis. Owing to the diversity of structure and the adjustability of synthesis, the metal-organic frameworks (MOFs) can enrich this important research field in the form of constructing a photoelectrode. In addition to solving the problems of difficult recovery for powder and the easy recombination for carriers in photocatalysis, MOFs and their derivatives-modified photoelectrodes can reasonably adjust the PEC activity at the molecular level and increase the contact area between the electrolyte and electrode, thereby facilitating the diffusion of electrolyte and reaction substrate in the electrode. In this review, we comprehensively reviewed representative studies in this area. Firstly, functions of MOFs in photoelectrodes are outlined, and the various synthesis strategies of MOFs-modified photoelectrodes are elaborated. Subsequently, special attention has been paid to the application and mechanism of MOFs-modified photoelectrodes (MIL, ZIF, UiO and PCN) in photo-electrochemistry. And we discuss the stability, reproducibility and reusability of MOFs-modified photoelectrodes. Finally, the challenges and improvements of MOFs-modified photoelectrodes in promoting practical application are proposed. Overall, MOFs and their derivatives-modified photoelectrodes achieved the integration of adsorption, photocatalysis and electrocatalysis. Notably, the research in this field is in infancy, many improvements are required before practical applications.