Tungsten ditellurium (WTe) is one of most important layered transition metal dichalcogenides (TMDs) and exhibits various prominent physical properties. All the present methods for WTe preparation need strict conditions such as high temperature or cannot be applied in large scale, which limits its practical applications. In addition, most studies on WTe focus on its physical properties, whereas its electrochemical properties are still illusive with little investigation. Here, we develop a facile and scalable two-step method to synthesize high-quality WTe nanoribbon crystals with 1T' Weyl semimetal phase for the first time. Highly crystalline 1T'-WTe nanoribbons can be obtained on a large scale through this two-step method. In addition, the electrochemical tests show that WTe nanoribbons exhibit smaller overpotential and much better hydrogen evolution reaction catalytic performance than other tungsten-based sulfide and selenide (WS, WSe) nanoribbons of same morphology and under same preparation conditions. WTe nanoribbons show a Tafel slope of 57 mV/dec, which is one of best values for TMD catalysts and about 2 and 4 times smaller than that for 2H-WS nanoribbons (135 mV/dec) and 2H-WSe nanoribbons (213 mV/dec), respectively. 1T'-WTe nanoribbons also show ultrahigh stability in 5000 cycles and 20 h at 10 mA/cm. The better performance is attributed to high conductivity of semimetallic 1T'-phase-stable WTe nanoribbons with one or two order higher charge-transfer rate than normally semiconducting 2H-stable WS and WSe nanoribbons. These results open the door for electrochemical applications of Weyl semimetallic TMDs.
Molybdenum ditelluride (MoTe2), as a member of two dimentional transition metal dichalcogenides (2D TMDCs), has been drawing scientists’ attention due to its susceptible phase transition. Here, we studied the phase transition process of MoTe2 with tellurization reaction step by step. In the process of tellurization reaction, the 1T’ MoTe2 would firstly convert to an intermediate phase (1T’@ 2H MoTe2) and then slowly convert to 2H MoTe2 instead of forming a direct phase transition from 1T’ MoTe2 to 2H MoTe2. This result might inspire the phase engineering of other 2D TMDCs and the exploration of potential device design.
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