Thickness-modulated and interface-engineered MoS2/TiO2 heterostructures as a highly active and inexpensive cathode for reverse electrodialysis

Molybdenum disulfide (MoS2) is considered to be promising two-dimensional material in potential applications because of its superior properties. Herein, our work suggests another important application as an inexpensive and highly active cathode material in reverse electrodialysis (RED). The MoS2 (8, 36, 76, 100 nm)/rutile-phase TiO2/Ti (MoS2/rpTiO2/Ti) heterostructures were successfully prepared with the randomly layered and oblique 1T/2H-MoS2 by one-step chemical vapor deposition of starting precursors in a closed reactor. The MoS2/rpTiO2/Ti reveals a thickness-dependent RED performance. Moreover, the MoS2 synthesis after sulfur modification of Ti surface (MoS2/smrpTiO2/Ti) increases the gross power density and reduces internal resistance of RED stack, indicating that the interfacial engineering between MoS2 and rpTiO2 improves both the catalytic activity and charge transfer efficiency. As a result, the highest gross power density of approximately 270 W/m2electrode was achieved using a RED stack mounted with 50-cell-pair of ion exchange membranes, which is comparable to that of platinum. Our work not only suggests that the MoS2/smrpTiO2/Ti heterostructure shows grate potential in RED stack, but also provides the importance of interface engineering between MoS2 and TiO2 through sulfate-bridge and sulfur-doping in MoS2-based electrocatalytic devices.