Topology conversion of 1T MoS2 to S-doped 2H-MoTe2 nanosheets with Te vacancies for enhanced electrocatalytic hydrogen evolution

Abstract

Metastable 1T' MoTe 2 has attracted much attention as a cost-effective electrocatalyst for hydrogen evolution reaction (HER) in recent years. However, few studies were done over common stable 2H phase because it often exhibits inferior performance. Herein, stable 2H MoTe 2 with S-doped Te vacancies has been synthesized by one-step telluride conversion of 1T MoS 2 at 700°C under Ar/H 2 atmosphere. It is demonstrated that the synergistic effect of S-doping and Te vacancies changes the electronic structures of the catalyst. Density functional theory (DFT) studies show that plentiful electrons accumulate on the surface S atoms in S-doped Te vacancies of 2H MoTe 2 catalyst, which may be as active sites to promote HER. Moreover, the as-synthesized catalyst can be directly used as working electrode, and realizes current density of 100 mA cm −2 at overpotential of 217 mV with Tafel slope of 94 mV dec −1 . This work stimulates intensive studies on the activation of inert phase of other nanocatalysts towards various reactions.

Facile hydrothermal synthesis of layered 1T′ MoTe2 nanotubes as robust hydrogen evolution electrocatalysts

“…As for the Mo 3d ( Figure 4B ), the peaks at 227.8 and 231.1 eV should be ascribed to Mo 3d 5/2 and Mo 3d 3/2 , similarly two observed peaks at 232.5 eV and 235.6 eV related to Mo-O bonds due to dynamic surface states. These findings are consistent with those of previous studies ( Zazpe et al, 2021 ; Wang et al, 2021 ). Figure 4C shows the Raman spectrum of the as-synthesized MoTe 2 nanotubes under a 532 nm laser, where the peaks situated at 115 cm −1 , 135 cm −1 , and 158 cm −1 correspond to the A g modes.…”

“…As shown in Figure 2A, an individual nanotube manifested a distinct tubular structure with a diameter of 200 nm and length of approximately 2 μm, on which thin sheets were uniformly distributed. The clear lattice stripes with a spacing of 0.71 nm are assigned to the (0 0 2) plane of the monoclinic MoTe 2 crystal from the HRTEM image in Figure 2B, which is slightly larger than that of the standard MoTe 2 crystal; the curved lattice fringe represents the characteristics of the layered TMDs nanosheets obtained by the wet chemical method (Lei et al, 2018;Wang et al, 2021, Zazpe et al, 2021. STEM-EDX mapping performed on a selected individual MoTe 2 nanotube revealed a uniform and homogeneous elemental distribution of Te and Mo in the integrated MoTe 2 nanotube (Figure 2C).…”

In situ polymerization confinement synthesis of ultrasmall MoTe2 nanoparticles for the electrochemical detection of dopamine

“…The intensity ratios of the D band to the G band ( I D / I G ) of NC and MoTe 2 /NC were found to be 0.98 and 1.12, which proves the existence of disorder defects because the introduction of MoTe 2 reduces the crystallization degree of the NC structure. 42–44 Otherwise, the specific bands at ∼78.4 cm −1 , ∼162.0 cm −1 , and ∼258.5 cm −1 of MoTe 2 /NC are also consistent with the vibrational modes of out-of-plane A g for MoTe 2 , showing the successful synthesis of MoTe 2 . 38…”

“…S7, The intensity ratios of the D band to the G band (I D /I G ) of NC and MoTe 2 /NC were found to be 0.98 and 1.12, which proves the existence of disorder defects because the introduction of MoTe 2 reduces the crystallization degree of the NC structure. [42][43][44] Otherwise, the specific bands at ∼78.4 cm −1 , ∼162.0 cm −1 , and ∼258.5 cm −1 of MoTe 2 /NC are also consistent with the vibrational modes of out-of-plane A g for MoTe 2 , showing the successful synthesis of MoTe 2 . 38 In the synthesis process, the Mo atoms in the precursor are captured by N in the initial pyrrole polymerization, where Mo is in situ stabilized on the support through the Mo-N bond, which protects MoTe 2 from aggregation in the following telluride reaction.…”

Metallic 1T′-MoTe2 Nanoparticle-Incorporated Graphene for Enhanced High Current Hydrogen Evolution and Supercapacitor Performance

“…Due to their specific atomic arrangement and excellent physicochemical properties, transition metal dichalcogenides (TMDs) are a class of hot materials used in catalysis, photovoltaic batteries, and energy storage equipment . Among various TMDs, with the characteristics of thermodynamic stability, small band gap, and comparable conductivity, metallic 1T′-MoTe 2 has the capacity to be applied for energy conversion and storage. , It can be prepared by chemical vapor deposition, molecular beam epitaxy, and high-temperature colloidal chemistry . These methods usually resulted in the formation of MoTe 2 nanosheets because of its native layered feature.…”