Constructing heterostructure of CeO2/WS2 to enhance catalytic activity and stability toward hydrogen generation

Transition metal disulfides (TMD) are considered as promising catalysts for hydrogen evolution reaction (HER) due to their unique structural and electronic properties. However, as a representative, the tungsten disulfide (WS2) shows an insufficient HER performance and is still needed to be further improved. Herein, we report the synthesis of CeO2-modified WS2 nanosheets with abundant heterostructures on carbon cloth (CeO2/WS2/CC) as an efficient self-supported integral electrode for HER. Experimental results and theoretical calculations imply that the intimate electronic interaction between CeO2 and WS2 promotes the production of more oxygen vacancies in CeO2 to regulate the electronic structure of WS2, endowing extra active sites, high electron transfer efficiency, and downshifted d-band center of W, which can lead to thermoneutral hydrogen adsorption Gibbs free energies (Delta G(H*)) and thus boosts HER. The optimized CeO2/WS2/CC electrode displays an improved HER performance with an overpotential of 128 mV at 10 mA cm(-2) in 0.5 M H2SO4 aqueous solution, 87 mV smaller than that of the WS2/CC electrode. Meanwhile, it also could maintain a 20 h of stable HER activity. Our work provides an effective approach to achieve various hybrid catalysts of rare earth compounds-transition metal compounds with highly active sites for superior electrocatalysis.

Automated summary

In this study, CeO2-modified WS2 nanosheets were synthesized for HER. The results showed that CeO2 promoted the formation of more active sites on WS2, improving the electron transfer efficiency and boosting the HER reaction. The optimized CeO2/WS2 electrode exhibited a better HER performance with a lower overpotential compared to the WS2 electrode, and maintained stable HER activity for 20 hours.