Hydrogen Stabilized RhPdH 2D Bimetallene Nanosheets for Efficient Alkaline Hydrogen Evolution

Abstract

The design of catalysts with high activity and robust stability for alkaline hydrogen evolution reaction (HER) remains a great challenge. Here, we report an efficient catalyst of two-dimensional bimetallene hydrides, in which H atoms stabilize the rhodium palladium bimetallene. The system exists because of the introduction of H that is in situ chemically released from the formaldehyde solution during the synthesis. This provides a highly stable catalyst based on an unstable combination of metal elements. Density functional theory calculations show the H is confined by electronic interactions and the Miedema rule of reverse stability of the RhPd alloy. The obtained catalyst exhibits outstanding alkaline HER catalytic performance with a low overpotential of 40 mV at 10 mA cm −2 and remarkable stability for over 10 h at 100 mA cm −2 . The experimental results show that the confined H improve the activity, while the ultrathin sheet-like morphology yields stability. Our work provides guidance for synthesizing high-activity catalysts by confining heteroatoms into the crystal lattice of bimetallene and also a very novel mechanism for the growth of bimetallene made of highly immiscible components.

Atomic Thickness Catalysts: Synthesis and Applications

“…A single-layer of Rh NSs was prepared by this way in the benzyl alcohol solvent including Rh(acac) 3 , PVP at 180 °C for 8 h. [46] More recently, Fan et al has successfully synthesized H-atom confined stable RhPd-H bimetallene in the formaldehyde solution, including Pd(acac) 2 , Rh(acac) 3 , and PVP. [3] Although the phase diagram of Rh−Pd exhibited a miscibility gap beyond 1100 K ( Figure 4A), RhPd-H bimetallene showed outstanding durability. The ultrahigh stability was owing to the H incorporation in spite of no stable hydride for Rh and week H bonding for Pd ( Figure 4B,C).…”

“…[7,[17][18][19] The ATCs including metals (alloys), LDHs, TMDs, TMOs, carbon based materials, are endowed with higher specific surface and density of unsaturated atoms, providing ideal properties with low-cost, highstability and excellent performance for the energy conversion applications. [3,11,18,[20][21][22][23][24] Exciting breakthroughs of various kinds of ATCs with a controllable morphology, domain size, structure, and composition have been made. [18,25] For instance, Guo's group successfully prepared a free-standing PdMo bimetallene with a thickness of 4-atom, giving a significantly higher atomic utilization >0.5 and a much larger mass activity of oxygen reduction reaction compared with commercial Pt/C and Pd/C, respectively.…”

“…The vertical growth on the salt surface is mainly restrained by precursor depletion, giving rise to the synthesis Reproduced with permission. [3] Copyright 2020, American Chemical Society. G,H) Low-magnification TEM image and HRTEM image of Co-Bi 3 O 4 Br, respectively.…”

“…Apart from the non-noble metal electrocatalysts, noble metal based ATCs have also developed via constructing alloying nanostructures (PtNi, [41,123] RuCo [23,33] ) through introducing metal-oxygen bonds as water dissociation sites [124] and incorporating H atoms. [3] Fan et al designed a metal alloy hydride of RhPd-H bimetallene NSs and it achieved highly effective performance for HER in alkaline solution. [3] The H confinement was in situ formed via the formaldehyde dissociation during the synthesis to further stabilize the RhPd alloy according to the DFT results.…”

“…However, clean H 2 and liquid fuels (formic acid, methanol, ethanol, and so on) are demanded in large-scale. [1] Clean H 2 fuels obtained by water splitting is admitted as an efficient way to fulfill the future H 2 / air fuel cell, [2][3][4][5] while carbon dioxide reduction is a renewable way to obtain liquid fuels such as formic acid, methanol. [6,7] Among them, the most critical thing is to develop the high efficiency, remarkable active and stable catalysts for energy conversion related reactions.…”