Hierarchically Ordinated Two-Dimensional MoS2 Nanosheets on Three-Dimensional Reduced Graphene Oxide Aerogels as Highly Active and Stable Catalysts for Hydrogen Evolution Reaction

Abstract

Hydrogen gas (H2) is being intensively proposed as a next-generation clean energy owing to the depletion of fossil fuels. Electrochemical water splitting is one of the most promising processes for hydrogen production. Furthermore, many efforts focusing on electrochemical water splitting have been made to develop low-cost, electrochemically active, and stable catalysts for efficient hydrogen production. MoS2 has emerged as an attractive material for developing catalysts for the hydrogen evolution reaction (HER). Hence, in this study, we design hierarchically ordinated two-dimensional (2D) MoS2 nanosheets on three-dimensional (3D) reduced graphene oxide (rGO) (H-2D/3D-MoS2-rGO) aerogel structures as a new class of electrocatalysts for the HER. We use the one-pot hydrothermal synthesis route for developing high-performance electroactive materials for the HER. The as-prepared H-2D/3D-MoS2-rGO contains a unique 3D hierarchical structure providing large surface areas owing to the 3D porous networks of rGO and more active sites owing to the many edge sites in the MoS2 nanosheets. In addition, the H-2D/3D-MoS2-rGO structure exhibits remarkable electrochemical properties during the HER. It shows a lower overpotential than pure MoS2 and excellent electrochemical stability owing to the large number of active sites (highly exposed edge sites) and high electrical conductivity from the rGO structure.

A GO/CoMo3S13 chalcogel heterostructure with rich catalytic Mo–S–Co bridge sites for the hydrogen evolution reaction

“…4 However, the quantitative XPS analysis of the Co 2p area ratio before and after the HER test of the 40% GO/CoMo 3 S 13 (1 : 1) chalcogel catalyst exhibits a decrease of Co to 77% of the initial composition (Table S4†), revealing a slight decay of catalytic performance of the 40% GO/CoMo 3 S 13 (1 : 1) chalcogel in acidic media after 2000 cycles. As shown in Table S6,† other catalytic systems such as transition metal dichalcogenides (TMDs):(2H, 1T) MoS 2 flakes, 44 (2H, 1T) WS 2 nanosheets, 45,46 and various molybdenum sulfide aerogel catalysts, such as 2D/3D-MoS 2 –rGO aerogel, 47 CNT aerogel/MoS x , 28 and CoMoS x /NF xerogels, 48,49 were chosen to evaluate the catalytic efficiency of the 40% GO/CoMo 3 S 13 (1 : 1) chalcogel and the CoMo 3 S 13 (1 : 1) on Ni foam (NF) xerogel for the HER. According to the references, the MoS 2 and WS 2 materials showed inferior HER catalytic performance in acidic media compared to the performance of the 40% GO/CoMo 3 S 13 (1 : 1) chalcogel (Table S5†).…”

Emerging transition metal and carbon nanomaterial hybrids as electrocatalysts for water splitting: a brief review

“…Some of transition metal based electrocatalysts, 73 including nickel based materials, 74–77 cobalt nitrides, phosphides and chalcogenides, 78–81 molybdenum sulfides, 49,82–84 molybdenum borides, 85–87 and transition metal alloy borides, supported on CNMs, 88 have shown activities comparable with state-of-the-art Pt-based materials for HER. Among them, nanocrystalline nickel has the lowest Gibbs free energy for hydrogen adsorption (Δ G H* ), and is considered the most promising transition metal for HER catalysis.…”

“…44–46 Similarly, graphene oxide (GO) 47 and reduced graphene oxide (rGO) render more active sites, where adsorption of intermediates takes place resulting in improved catalytic efficiency. 35,48–50 Moreover, CNMs doped with heteroatoms like nitrogen, 39,46,48,51 phosphorus, 52,53 sulfur, 53–55 and boron 29,56,57 could reduce catalyst corrosion.…”

“…In the current state of development, carbon nanomaterials supported transition metal based electrocatalysts for water splitting can be classified into hybrids of transition metal based materials with pure CNMs, N-doped, B-doped and dual N,B-doped CNMs as shown in Fig. 1 with the abbreviations of TM/CNMs, TM/N-CNMs, TM/B-CNMs and TM/N,B-CNMs, respectively, where some examples for HER (H-2D/3D-MoS 2 -rGO), 49 OER (boron doped graphene oxide encaged Ni 3 N nanoparticles, 64 and OWS (N,B : Mo 2 C@BCN 65 and CoFe@N-C 66 ) are also demonstrated. In this article, recent advances on these catalysts integrating transition metal-based materials with pure CNMs as well as heteroatom doped CNMs to attain enhanced efficiency and stability is reviewed, the effects of boron, nitrogen and dual-N,B doping on the structure of carbon nanomaterials and their performance towards HER and OER are emphatically discussed, and the present challenges and future research prospects are also proposed.…”

Recent Progress in Graphene-Based Electrocatalysts for Hydrogen Evolution Reaction

“…Hyeonggeun et al [ 110 ] hierarchically arranged 2D MoS 2 nanosheets on 3D rGO aerogels by one-pot hydrothermal synthesis, which exhibited better catalytic performance in the hydrolysis of HER due to the porous network and more active sites in 3D reduced graphene oxide aerogels. Similarly, Rajendra et al [ 111 ] also introduced CoS 2 in graphene aerogels by hydrothermal method to obtain a composite CoS 2 /graphene aerogel electrocatalyst with an overpotential as low as 160 mV at a current density of 10 mA·cm −2 .…”