Activation of Electrocatalytic CO ₂ Methanation on Defective 1T′ Phase TMDCs

The electrochemical reduction of carbon dioxide (CO2RR) using two-dimensional transition metal dichalcogenides (TMDCs) has emerged as a promising technique for reducing atmospheric carbon dioxide (CO2). However, most recent studies have primarily focused on semiconducting 2H phase TMDCs, leaving semimetallic 1T′ phase TMDCs, such as molybdenum ditelluride (MoTe2) and tungsten ditelluride (WTe2), which are stable in ambient conditions, largely unexplored. Our findings reveal that Te vacancies on WTe2 can activate the inert basal plane of WTe2 for CH4 production without suffering from the competing hydrogen evolution reaction. The key to CH4 production is to mitigate *OH poisoning on the active sites. According to our structural and statistical analysis, this can be achieved through the modulation of the metal–oxygen bond length and substrate deformation, both of which can be controlled through defect engineering. Our findings demonstrate that defect engineering holds great potential to activate the basal plane of 1T′ TMDCs for the CO2RR and encourage further research on phase engineering for electrocatalysis.