On the hydrogen evolution reaction activity of graphene–hBN van der Waals heterostructures

Abstract

Although graphene technology has reached technology readiness level 9 and hydrogen fuel has been identified as a viable futuristic energy resource, pristine atomic layers such as graphene are found to be inactive towards the hydrogen evolution reaction (HER). Enhancing the intrinsic catalytic activity of a material and increasing its number of active sites by nanostructuring are two strategies in novel catalyst development. Here, electrocatalytically inert graphene (G) and hexagonal boron nitride (hBN) are made active for the HER by forming van der Waals (vdW) heterostructures via vertical stacking. The HER studies are conducted using defect free shear exfoliated graphite and hBN modified glassy carbon electrodes via layer by layer sequential stacking. The G/hBN stacking pattern (AA, AB, and AB') and stacking sequence (G/hBN or hBN/G) have been found to play important roles in the HER activity. Enhancement in the intrinsic activity of graphene by the formation of G/hBN vdW stacks has been further confirmed with thermally reduced graphene oxide and hBN based structures. Tunability in the HER performance of the G/hBN vdW stack is also confirmed via a three-dimensional rGO/hBN electrode. HER active sites in the G/hBN vdW structures are then mapped using density functional theory calculations, and an atomistic interpretation has been identified.

Two‐Dimensional Amorphous Cr2O3 Modified Metallic Electrodes for Hydrogen Evolution Reaction

“…HER is highly dependent on the pH of the electrolyte and it is facile at low pH (in acidic medium) due to the availability of proton for electro‐reduction. It is now clear that water electrolysis follows different mechanisms in acidic and alkaline media …”

“…The proton or hydronium ions adsorption ( H abs ) on the active site is the first step in HER, and M−H (M stands for metal or other active sites) adsorption energy decides the activity of an electrocatalyst . For an ideal electrocatalyst, it has to be in thermoneutral, that is, Δ G H ∼0 eV – meaning adsorption and desorption (of H 2 ) energy should be optimum .…”

“…The proton or hydronium ions adsorption ( H abs ) on the active site is the first step in HER, and M−H (M stands for metal or other active sites) adsorption energy decides the activity of an electrocatalyst . For an ideal electrocatalyst, it has to be in thermoneutral, that is, Δ G H ∼0 eV – meaning adsorption and desorption (of H 2 ) energy should be optimum . The reported theoretical frameworks for 2D materials modified metals mostly hold in an acidic medium where either adsorption/desorption energy optimization or Fermi level modification are proposed as the basic mechanism aiding for higher activities .…”

Molybdenum disulfide–graphene van der Waals heterostructures as stable and sensitive electrochemical sensing platforms

“…Hence, such interfacing is found to be resulting in new solids of interesting electronic, optical, and electrochemical properties [30][31][32]. It is shown that even pristine graphene surfaces become electrochemically active while forming vdWs structures with MoS 2 and hBN [33,34]. Furthermore, vdWs structures of graphene with MoS 2 monolayers (MS) were found to provide enhanced hydrogen evolution catalytic activity compared with bare MS along with the enhanced stability even in harsh acid conditions and the interfacial charge transfer from graphene to MS was also established [35].…”

Theoretical Study of Two‐Dimensional ZrO2/g‐C3N4 Sandwich Structure Loaded Noble‐Metal Rh Single‐Atom Catalysts

“…Hakim Faraji's team designed CuS‐ZrO 2 vdWs heterostructure material and found that it has a high absorption intensity in the uv range and has a promising future in the field of photocatalysis [13] . Based of g‐C 3 N 4 semiconductor heterostructure (the second type of heterojunction) photocatalyst has an appropriate band gap and a low degree of recombination of carriers and holes, which is very favorable for photocatalysis [14,15] . g‐C 3 N 4 has a relatively suitable E g ≈2.77 eV and CBM about −1 V, and its spectral absorption covers both ultraviolet and visible regions, and its electron reduction ability can meet the requirements of H 2 reduction [16] .…”