Two-dimensional layered MoS2: rational design, properties and electrochemical applications

The layered molybdenum chalcogenide MoS2 has attracted wide attention due to its potential electrochemical applications. Based on its unique physical and chemical properties, numerous advances have shown that nanostructured MoS2, with the advantages of low cost and outstanding properties, is a promising candidate for environmentally benign energy conversion and storage (ECS) devices. Nowadays, in order to lessen the reliance on fossil fuels, the production of hydrogen from water splitting has become an important issue. Hence, developing catalysts composed of earth-abundant elements that possess activities comparable to those of noble metals is of great urgency. According to DFT calculations in terms of HER free-energy diagrams, MoS2 could be used as an effective substitute for noble metals. Meanwhile, MoS2 with various structures has also been applied in the field of energy storage, including batteries and supercapacitors. Additionally, due to their layer-dependent electrical properties, MoS2-based electrochemical devices have been applied as sensors for a variety of chemicals. In this review, we summarize recent advances in the development of MoS2 with high-performance in various electrochemical domains, and recent progress in discovering the mechanisms underlying the enhanced activity. Moreover, we summarize the critical obstacles facing MoS2, and discuss strategies for further improving its activity. Lastly, we offer some suggestions on the pathways toward achieving high performance competitive with noble metal counterparts, and perspectives on practical applications of MoS2 in the future.