Development of Multilayer MoS₂ for photocatalytic applications

Molybdenum disulfide (MoS₂) has been regarded as a promising material for solving the current fossil fuel shortage and environmental problems due to its remarkable semiconducting and photocatalytic properties. However, monolayer MoS₂ has attracted most of the scientific interest, leaving its multilayer counterpart neglected. Multilayer or bulk MoS₂ has its own advantages, e.g., low cost and restricted recombination of photoexcited electrons and holes due to its indirect band. The major barrier for its application is the large proportions of inert basal planes. Given this, activating the inert sites of multilayer MoS₂ would develop a practical candidate for the photocatalyst family. Efforts have been devoted to introducing S vacancies through various sophisticated techniques; however, most of these are not applicable in real-life applications.

In our recent work, we proposed a nanofabrication strategy to join transition metal nanoparticles to MoS₂ via silver buffer layers [1,2]. Typically, nickel nanoparticles up to 200 nm could be chemically attached to both the edges and basal planes of multilayer MoS₂ through this method, leading to activated MoS₂ with greatly enhanced photocatalytic hydrogen evolution efficiency. Further investigation has also revealed its feasibility for photodegradation of organic pollutants in natural water. Therefore, hydrogen production and water purification could be achieved simultaneously. Based on high-resolution XPS analysis, we believe that the successful nickel doping and high photocatalytic performance can be attributed to the effective bonding between Ni and MoS₂, which serves as an expressway for electrons crossing between the semiconducting side and the active metallic sites.

[1] X. Shi, M. Zhang, X. Wang, et al. Nickel nanoparticle-activated MoS₂ for efficient visible light photocatalytic hydrogen evolution. Nanoscale, 2022, 14, 8601−8610.

[2] X. Shi, S. Posysaev, M. Huttula, et al. Metallic contact between MoS₂ and Ni via Au nanoglue. Small, 2018, 14, 1704526.