Dense Platinum/Nickel Oxide Heterointerfaces with Abundant Oxygen Vacancies Enable Ampere‐Level Current Density Ultrastable Hydrogen Evolution in Alkaline

Abstract

Platinum (Pt) remains the benchmark electrocatalyst for alkaline hydrogen evolution reaction (HER), but its industry-scale hydrogen production is severely hampered by the lack of well-designed durable Pt-based materials that can operate at ampere-level current densities. Herein, based on the original oxide layer and parallel convex structure on the surface of nickel foam (NF), a 3D quasi-parallel architecture consisting of dense Pt nanoparticles (NPs) immobilized oxygen vacancy-rich NiO x heterojunctions (Pt/NiO x -O V ) as an alkaline HER catalyst is developed. A combined experimental and theoretical studies manifest that anchoring Pt NPs on NiO x -O V leads to electronrich Pt species with altered density of states (DOS) distribution, which can efficiently optimize the d-band center and the adsorption of reaction intermediates as well as enhance the water dissociation ability. The as-prepared catalyst exhibits extraordinary HER performance with a low overpotential of 19.4 mV at 10 mA cm −2 , a mass activity 16.3-fold higher than that of 20% Pt/C, and a long durability of more than 100 h at 1000 mA cm −2 . Furthermore, the assembled alkaline electrolyzer combined with NiFe-layered double hydroxide requires extremely low voltage of 1.776 V to attain 1000 mA cm −2 , and can operate stably for more than 400 h, which is rarely achieved.

Strain‐Regulated Pt–NiO@Ni Sub‐Micron Particles Achieving Bifunctional Electrocatalysis for Zinc–Air Battery

“…Moreover, the DOS (Figure 3f) contribution of strain-regulated Ni in Pt@Ni(111) is improved around the Fermi level, revealing that the d orbital of Ni lose electrons, which is transferred to Pt for forming an empty orbital, further agreeing with the result of charge difference. [49] And, the d-band center of Pt induced by the strain-regulated Ni moves positively from −1.56 to −1.50 eV in Figure 3g, resulting in the shift of more antibonding orbitals to the Fermi level (Figure S13b, Supporting Information), leading to effectively optimize the adsorption intensity of the intermediate (OH*) and facilitate the desorption of H 2 O. [36] According to the above analysis, it could be inferred that strainregulated Pt-NiO@Ni SP possesses an excellent bifunctional performance for ORR and OER.…”

Tailoring supports for enhancing the electrocatalytic hydrogen evolution performance of platinum species: a review

“…However, the kinetics of these reactions can differ significantly, leading to different efficiencies and selectivities of electrocatalysts in neutral and alkaline media. 25 Particularly, H* is derived by splitting water in alkaline solution, which requires additional energy and results in a slower kinetic rate. For example, the reaction rate of Pt in alkaline media is significantly slower, often by two to three orders of magnitude, compared to that in acidic media.…”

Multisite synergistic-modulating elementary steps for efficient alkaline hydrogen evolution via NiCu/NiMoOx nanocomposites

“…How the OH ads and H ads adsorption energy affects the overall HER rate is inconclusive. 6,29,30 Whether or not there is an optimal water dissociation promoter is still unknown. 31,32 In the research described herein, we designed NiCu and amorphous phase NiMoO x heterostructure (NiCu/MoO x ) catalysts with tunable surface chemistry as a model to obtain insights into the aspects discussed previously.…”

“…How the OH ads and H ads adsorption energy affects the overall HER rate is inconclusive. 6,29,30 Whether or not there is an optimal water dissociation promoter is still unknown. 31,32…”