Emerging trends in metal-organic framework (MOFs) photocatalysts for hydrogen energy using water splitting: A state-of-the-art review

Various photocatalysts have been developed for photocatalytic water splitting-one of the most important processes that produces dihydrogen as clean energy for fuel cells. The successful achievements for this application are based mainly on transition metal oxides and some metal sulfides/nitrides. Recently, metal-organic frameworks (MOFs), a class of hybrid functional materials comprising organic backbone tethered infinitively in limitless way by metal-oxide clusters, both of which can be customized accurately at the molecular level for targeted applications, have been able to photocatalytically degrade water. Apart from representing an array of intrinsic structural and physicochemical characteristics, MOFs are well susceptible for various post-synthetic modifications to address specific challenges. Despite years of research in this field and a good number of seminal studies, further efforts should be geared toward the improvement of light absorption and stability of MOFs, which are the principal challenges that should be overcome. This review includes the most recent research that has been committed to MOFs materials for photocatalytic water-splitting applications. It also encompasses a variety of synthetic techniques and post-modifications that have been employed to increase the performance of MOFs. In addition, a brief discussion of the techno-feasibility analysis of water splitting has been offered, extending the conversation to include current challenges and future direction recommendations. The recent advancements of using MOF photocatalysts for water splitting are further described in a way that benchmark achievements and limitations are considered so that the readers can imagine the big picture in this field and pay considerable attention to future solutions.