High Activity Hydrogen Evolution Catalysis by Uniquely Designed Amorphous/Metal Interface of Core–shell Phosphosulfide/N‐Doped CNTs

Abstract

nonprecious catalysts toward the hydrogen evolution reaction (HER) for a widespread of sustainable energy storage and conversion. [6] To date, a variety of nonprecious-metalbased catalysts, especially, the family of earth-abundant transition metal compounds of nitrides, [7,8] carbides, [9,10] chalcogenides, [11][12][13][14] and phosphides, [15][16][17][18][19] have been explored for HER catalysts. It has been reported that novel material designs relying on chemical synthesis or crystalline engineering (facets, polymorph, interface, defect, doping, surface modification) can enhance HER activity. Nonetheless, in order to avoid the undesired charge transfer loss and gas bubble trap, a welldesigned, atomically and electronically coupled interface between fully tailored catalyst morphology and high surface area of conductive support turned out to be essential. [20] In this regard, unlike widely used oxygen functionalized carbon supports with severely damaged electrical properties, electron-rich N-doped carbon nanotubes (CNTs) and graphene not only provide additional electrons to graphitic carbons to maintain high electroconductivity but also afford novel synthesis platform for the synergistic hybrid structures of ultimate practical utilization. [12] We present a unique nanostructured core-shell hybrid catalysts composed of transition metal phosphosulfide (CoP@PS, MoP@PS, CoMoP@PS) decorated at N-doped carbon nanotubes (NCNTs). Nanoscale thick amorphous MS x (M = Co, Mo, CoMo) layers were directly deposited on the large area NCNT surfaces by low-temperature wet chemical process and subsequent phosphidation. Quasi-amorphous phosphosulfide (PS) nanoshells are formed around the crystalline core particles, whose S-doping effect greatly enhances the HER activity of nanoparticles to attain the noticeable HER activity of ≈ −80 mV @ −10 mA cm −2 with excellent durability. It is noteworthy that this is the first report for core-shell transition metal phosphosulfide nanostructure formation with a clear evolution of amorphous PS surface. The underlying catalytic mechanisms were investigated by density functional theory (DFT), which revealed the principal role of hybrid interfaces for the catalytic activity. Taken together, this hybrid offers one of the highest active nonnoble metal electrocatalysts ever reported thus far.A cost effective hydrogen evolution reaction (HER) catalyst that does not use precious metallic elements is a crucial demand for environment-benign energy production. The family of earth-abundant transition metal compounds of nitrides, carbides, chalcogenides, and phosphides is one of the promising candidates for such a purpose, particularly in acidic conditions. However, its catalytic performance is still needed to be enhanced through novel material designs and crystalline engineering. Herein, a chemically and electronically coupled transition metal phosphosulfide/N-doped carbon nanotubes (NCNT) hybrid electrocatalyst is fabricated via a two-step synthesis. The uniquely designed synthesis leads to the materia...

Atomically Dispersed Mo Sites Anchored on Multichannel Carbon Nanofibers toward Superior Electrocatalytic Hydrogen Evolution

“…Various adsorption sites have been tested, including the Mo site and C/N sites on the graphene layer, in which the Mo site is energetically favorable. As suggested by Nørskov et al, the Gibbs free energy of H adsorption (Δ G H* ) close to 0, namely, the small |Δ G H* |, is related to high performance in the HER. – From Figure b, one can see that all of the theoretical Δ G H* values are positive, indicating the relatively weak adsorption strength of hydrogen on the Mo atom. With the increase in bonded carbon atoms, the hydrogen adsorption is enhanced.…”

Microstructural Engineering of Heterogeneous P−S−Co Interface for Oxygen and Hydrogen Evolution

“…For the P 2p core level spectra (Figure c), the BE of P 2p 3/2 and P 2p 1/2 peaks assigned to P−Co for IN‐PSNCs‐3 is positively shifted from those for IN‐PSNCs‐2 and IN‐PSNCs‐5, further confirming abundant Co−P−S species form in disordered regions . In addition, the proportion of P−Co increases with S content, suggesting that S can inhibit the oxidation process of P . According to the above analysis, the atomic compositions and bonds in the disordered region at the grain boundaries in IN‐PSNCs‐3 is conjectured and shown in Figure d.…”

Dealloying Induced Manipulative Disruption of Ni2P–SnP Heterostructure Enabling Enhanced Hydrogen Evolution Reaction

“…The distinct core−shell structure facilitates in preventing the metal active sites from disintegration and enhances the interfacial area. 22,23 Doping/substitution in heteroatom as seen in previous works is known to further increase the performance by modulation of the electronic structure. NiCoP, 24,25 WMoP, 26 and NiMoP 27 significantly improved the electrocatalytic performance because of the synergy between different metal elements, which facilitates in exposing more active sites due to change in surface morphology or modulates the intrinsic electronic properties of the hybrids.…”