Morphology-controlled Tantalum Diselenide Structures as Self-optimizing Hydrogen Evolution Catalysts

Metallic layered transition metal dichalcogenides(TMDs)nanomaterials based on Group 5 transition metals are attracting substantial interests as alternative catalysts for hydrogen evolution reaction(HER).However,controllable preparation of tantalum diselenide(TaSe2)remains challenging,which has hindered the exploration on its application in HER.Herein,we develop a facile method named surface-assisted chemical vapor transport(SACVT)for controllable synthesis of TaSe2 plates and nanobelts,by regulating the molar ratio of selenium to tantalum and reaction temperature.Unique quasi-arrays and self-supported structure help TaSe2 nanobelt own more active sites and higher ability of charge transfer,so it is superior to TaSe2 plate in electrocatalytic HER.Interestingly,they both exhibit the ability to optimize their morphologies upon cycling for dramatically improved and robust electrocatalytic performance.The selfoptimized structures can increase the effective active surface by exposing more active sites on the basal-planes and edges,shorten the interlayer electron-transfer pathways at a thinned domain,and accelerate the charge transfer,which mainly derive from high basal-plane activity and weak interaction between layers of metallic TaSe2.This work provides a reliable way for controllable synthesis of different TaSe2 structures,motivating further efforts to explore new high-efficiency catalysts in the large family of metallic TMDs for electrochemical energy conversion.