Phase engineering of a multiphasic 1T/2H MoS₂ catalyst for highly efficient hydrogen evolution

Abstract

A multiphasic 1T/2H MoS2 electrocatalyst for hydrogen evolution, which exhibits excellent performances with a small Tafel slope of 46 mV dec−1, is developed by phase engineering via a simple hydrothermal route.

Synergistic Interlayer and Defect Engineering in VS2 Nanosheets toward Efficient Electrocatalytic Hydrogen Evolution Reaction

“…The DSC curve of the freshly prepared VS 2 in Figure S3b (Supporting Information) shows several obvious endothermic peaks at 70, 94, 203, and 266 °C, respectively, corresponding to the mass losses. The low‐temperature peaks are ascribed to the adsorbed water and inserted NH 3 molecules, and the other two high‐temperature peaks can be attributed to the inserted NH 4 + ions and octylamine molecules, respectively . In addition, the elemental analysis from EDX and XPS results for the freshly prepared solvothermal VS 2 nanosheets shows that the molar ration of V:S is 1:1.9, which is close to 1:2.…”

Defect Engineering of MoS2 and Its Impacts on Electrocatalytic and Photocatalytic Behavior in Hydrogen Evolution Reactions

“…Figure (a) shows the DTA/TG profile of the as‐prepared 1T/2H‐MoS 2 . An exothermic peak observed in the range of 160–250 °C is ascribed to the transition from 1T phase to 2H phase, which is much higher than the transition temperature of the monolayer 1T phase (95 °C), indicating that a higher stability of the 1T phase inserted in 2H phase than pure 1T‐MoS 2 . The exothermic peak in the range of 325–375 °C is ascribed to the release of inserted NH 4 + , which was introduced by molybdate hexahydrate and ammonia bicarbonate used as the precursors.…”

“…It is still a great challenge to synthesize 1T‐MoS 2 under mild synthetic conditions. Insertion of 1T‐MoS 2 into 2H‐MoS 2 as a phase defect is expected to be a potential method to enhance conductivity and to increase active sites for MoS 2 under relatively mild synthetic condition . Besides phase change, another strategy to promote catalytically performance of MoS 2 is the introduction of S‐vacancies into MoS 2 crystal structure .…”

Interlayer Nanoarchitectonics of Two‐Dimensional Transition‐Metal Dichalcogenides Nanosheets for Energy Storage and Conversion Applications

“…Improvement of electrical conductivity by intercalation of conductive NH 4 + ions into MoS 2 interlayers is considered to be responsible for the excellent HER performance. [141] Other examples of HER applications of interlayer-expanded MX 2 include 3D radially oriented MoS 2 nanospheres with an interlayer spacing of 0.707 nm, [98] vertically aligned Li-intercalated MoS 2 nanofilm with an interlayer spacing of 0.721 nm, [51] hollow structured MoS 2 micro/ nanospheres with an interlayer spacing of 0.78 nm, [142] MoS 2 nanoflowers assembled by amorphous nanosheets with an interlayer spacing of 0.80 nm, [143] multiphasic 1T/2H MoS 2 with an interlayer spacing of 0.93 nm, [93] oxygen-incorporated MoS 2 ultrathin nanosheets with an interlayer spacing of 0.95 nm, [77] MoS 2 /N-doped rGO nanocomposite with an interlayer spacing of 0.95 nm, [43] MoS 2x Se 2(1−x) nanotubes with an interlayer spacing of 0.98 nm, [144] MoS 2 nanosheets with an interlayer spacing of 1.01 nm, [145] 1T-MoSe 2 nanosheets with an interlayer spacing of 1.17 nm [82] and 1T-MoS 2 nanosheets with an interlayer spacing of 1.18 nm. [128] Poor intrinsic conductivity of semiconducting MX 2 suppresses the overall HER performance.…”

“…[90] Post annealing treatment can evaporate volatile species intercalated in the hydrothermal/ solvothermal MX 2 nanosheets and decrease the expanded interlayer spacing by restacking. [82,84,85,[91][92][93] …”