Synthesis of 1T-MoSe₂ ultrathin nanosheets with an expanded interlayer spacing of 1.17 nm for efficient hydrogen evolution reaction

Abstract

1T-MoSe2 nanosheets featuring expanded (002) interlayer spacings as large as 1.17 nm are prepared and demonstrated as an efficient electrocatalyst for the hydrogen evolution reaction.

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] …”

“…[43] [77] Copyright 2013, American Chemical Society, B) 1T-MoSe 2 , reproduced with permission. [82] Copyright 2016, The Royal Society of Chemistry, C) NH 3 -intercalated VS 2 , reproduced with permission. [83] Copyright 2011, American Chemical Society, D) NH 4 + -intercalated 1T-WS 2 , reproduced with permission.…”

“…When used as HER catalyst, the 1T-MoSe 2 nanosheets exhibit significantly improved activity with a small Tafel slope of 78 mV dec −1 and a low onset potential of 60 mV, which are better than those of the annealed 2H-MoSe 2 sample ( Figure 12E,F). [82] Composition modification is another route for tuning the electronic structure and conductivity of MX 2 . MoSe 2 monolayer has a much smaller direct bandgap (1.557 eV) than that (1.856 eV) of MoS 2 monolayer, hinting its higher conductivity.…”

“…For instance, our group recently reported flower-like assemblies of 1T-MoSe 2 nanosheets with an expanded interlayer spacing as large as 1.17 nm (81% expansion) by reacting MoCl 5 with SeO 2 in octylamine solvent at 180 °C ( Figure 5B). [82] VS 2 intercalated with NH 3 molecules (VS 2 ·NH 3 ) showing an expanded interlayer spacing of 0.92 nm was prepared through a hydrothermal route by reacting Na 3 VO 4 ·12H 2 O with thioacetamide (TAA) at 160 °C for 24 h ( Figure 5C). [83] Song and co-workers reported hydrothermal synthesis of nanoribbons of stable metallic 1T-WS 2 with an interlayer spacing of 0.95 nm by ammonia ions intercalation ( Figure 5D).…”