High phase purity of stable 1T-phase Co-doped WS2 for full pH hydrogen evolution reaction in water and seawater

Metallic 1T phase transition metal dichloride (TMDs) shows excellent catalytic activity for the hydrogen evo-lution reaction (HER), but stabilization of 1T phase TMDs is still challenging. Herein, the Finke-type POMs K-10[Co-4(H2O)(2)(PW9O34)(2)] [Co-4(PW9)(2)] was used for the first time as a precursor to obtaining size similar to 4 nm, highly dispersed 1T-WS2 in the hollow mesoporous carbon sphere (HMCS) by the effect of confinement, named 1T-CoWS/HMCS. 1T-WS2 was obtained based on the natural Co-W atomic interface of POMs and further enhanced dispersion at the molecular and nano scales. 1T-CoWS/HMCS only requires ultralow overpotential with high electrocatalytic surface area and robust stability in water and seawater. According to DFT calculations, the Co-S-edge site of 1T-CoWS significantly reduced the rate-limiting step of HER as the predominant active site. This work provides a worthy reference for the synthesis of high-quality metastable TMDs.