MoS2-CoS2 heteronanosheet arrays coated on porous carbon microtube textile for overall water splitting

Designing low-cost but efficient non-noble-metal bifunctional electrocatalysts is necessary for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in the process of water splitting. Herein, we report a self-standing bifunctional electrode by coating MoS2-CoS2 heteronanosheet arrays on porous carbon microtube textile (MoS2-CoS2@PCMT) for alkaline overall water splitting. The abundant MoS2-CoS2 heterogeneous interfaces with electronic interaction (confirmed by X-ray photoelectron spectroscopy) can optimize the adsorption free energies for HER and OER intermediates (supported by the theoretical calculation), making MoS2-CoS2@PCMT achieve lower overpotentials for HER and OER than Pt/C@PCMT and RuO2@PCMT at higher current density. In addition, the freestanding structure of PCMT and the tight adhesion with MoS2-CoS2 heteronanosheets facilitate MoS2-CoS2@PCMT a long-term durability. As a result, the MoS2-CoS2@PCMT parallel to MoS2-CoS2@PCMT couple show a relatively low water-splitting voltage of 1.59 V at 10 mA cm(-2), and demonstrate lower cell voltage than the benchmark Pt/C@PCMT parallel to RuO2@PCMT couple at higher current density. This work gives prominence to the design of self-standing electrode structure and coupling of transition metal dichalcogenides to improve the performance of electrocatalysts for water splitting.

Automated summary

Designing low-cost and efficient non-noble-metal bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for water splitting. In this study, a self-standing bifunctional electrode with MoS2-CoS2 heteronanosheet arrays on porous carbon microtube textile (MoS2-CoS2@PCMT) was developed for alkaline overall water splitting, showing lower overpotentials for HER and OER compared to Pt/C@PCMT and RuO2@PCMT at higher current density. The results highlight the importance of self-standing electrode structure and coupling of transition metal dichalcogenides for improving electrocatalyst performance in water splitting.