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

Abstract

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 (WS 2 ) shows an insufficient HER performance and is still needed to be further improved. Herein, we report the synthesis of CeO 2 -modified WS 2 nanosheets with abundant heterostructures on carbon cloth (CeO 2 /WS 2 /CC) as an efficient self-supported integral electrode for HER. Experimental results and theoretical calculations imply that the intimate electronic interaction between CeO 2 and WS 2 promotes the production of more oxygen vacancies in CeO 2 to regulate the electronic structure of WS 2 , 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 (ΔG H* ) and thus boosts HER. The optimized CeO 2 /WS 2 /CC electrode displays an improved HER performance with an overpotential of 128 mV at 10 mA cm −2 in 0.5 M H 2 SO 4 aqueous solution, 87 mV smaller than that of the WS 2 /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. • A monolithic CeO 2 /WS 2 /CC electrode with heterostructure of CeO 2 /WS 2 is fabricated. • The hybrid CeO 2 /WS 2 nanosheets structure is beneficial to exposing more active sites. • The electronic interaction between WS 2 and CeO 2 results in a superior HER activity. • The mechanism of HER over CeO 2 /WS 2 /CC electrode is clarified by DFT calculations.