N-Doped Sandwich-Structured Mo₂C@C@Pt Interface with Ultralow Pt Loading for pH-Universal Hydrogen Evolution Reaction

Abstract

Designing a unique electrochemical interface to exhibit Pt-like activity and good stability is indispensable for the efficient hydrogen evolution reaction (HER). Herein, we synthesize well-defined Mo 2 C@NC@Pt nanospheres with a sandwich-structured interface through a facile organic− inorganic pyrolysis and following reduction process. The obtained Mo 2 C@NC@Pt heterostructures with ultralow Pt loading are composed of well-dispersed Mo 2 C nanoparticles (NPs) inner layer, N-doped carbon layer, and ultrafine Pt NPs outer layer. Electrochemical measurements demonstrate that Mo 2 C@NC@Pt heterostructures not only exhibit superior HER activities than commercial Pt/C with small overpotentials of only 27, 47, and 25 mV to achieve a current density of 10 mA cm −2 in acidic, alkaline, and neutral media, respectively, but also possess favorable long-term stability in pH-universal solution. The improved reaction kinetics of Mo 2 C@NC@Pt heterostructures are mainly attributed to the unique sandwich-structured interface with well-defined Mo 2 C NPs encapsulated by carbon layers and Pt NPs well-dispersed on the carbon support, synergistic effects among Mo 2 C NPs, NC, and Pt NPs, high specific surface area, and N-doping into the catalysts. This facile approach not only provides a new pathway for preparing well-defined carbides but also gives insight into the development of low-Pt catalysts for the efficient HER.

Facile and Large‐Scale Fabrication of Sub‐3 nm PtNi Nanoparticles Supported on Porous Carbon Sheet: A Bifunctional Material for the Hydrogen Evolution Reaction and Hydrogenation

“…The comparison with other representative Pt‐based HER electrocatalysts reported recently (Table S1 in the Supporting Information), suggests that the the PtNi 2 @CNS‐600 electrocatalyst with lowest Pt content (0.074 wt %) has lower overpotential and Tafel slope. The exceedingly small Tafel slope of PtNi 2 @CNS‐600 shows that HER is possibly controlled by a Volmer–Tafel mechanism, in which recombination of absorbed H is the rate‐limiting step, which implies more favorable kinetics and faster reaction rate, consistent with the above results and confirmed by the Nyquist plot. The Nyquist plots of samples with iR correction were recorded at 0.238 V versus RHE (Figure S1 in the Supporting Information).…”

Surface and Interface Engineering: Molybdenum Carbide–Based Nanomaterials for Electrochemical Energy Conversion

“…Such unique architecture and high conductivity of Mo 2 C-based catalyst are responsible for the outstanding catalytic activity toward HER. Similar enhanced performances have also been investigated by the preparation of CNT/Mo x C, [131] the Mo x C/3D carbon foam, [132] the Mo x C/graphene, [133] and the Mo x C@N-carbon nanofibers structure. [128] Metal nanoparticles, such as Co, Ni, and Pt, [134][135][136] have been widely introduced to improve the electrochemical activity of catalysts for energy conversion.…”

“…Such unique architecture and high conductivity of Mo 2 C‐based catalyst are responsible for the outstanding catalytic activity toward HER. Similar enhanced performances have also been investigated by the preparation of CNT/Mo x C, [ 131 ] the Mo x C/3D carbon foam, [ 132 ] the Mo x C/graphene, [ 133 ] and the Mo x C@N‐carbon nanofibers structure. [ 128 ]…”

Synergistic effect of metallic nickel and cobalt oxides with nitrogen-doped carbon nanospheres for highly efficient oxygen evolution

“…The well-dispersed polymer nanospheres were synthesized via the polymerization of aniline and pyrrole using Triton X-100 as a surfactant, according to the procedure employed in our previous study [33]. To synthesize Ni 2+ ,Co 2+ @polymer nanospheres, the polymer nanospheres were dispersed in 20 mL of a solution containing the same amount of Ni(NO3)2 6H2O and Co(NO3)2•6H2O (nNi:nCo = 1:1) with strong ultrasonication to form homogeneous ink.…”