Efficient Hydrogen Oxidation Catalyzed by Strain‐Engineered Nickel Nanoparticles

Abstract

The hydroxide‐exchange membrane fuel cell (HEMFC) is a promising energy conversion device. However, the development of HEMFC is hampered by the lack of platinum‐group‐metal‐free (PGM‐free) electrocatalysts for the hydrogen oxidation reaction (HOR). Now, a Ni catalyst is reported that exhibits the highest mass activity in HOR for a PGM‐free catalyst as well as excellent activity in the hydrogen evolution reaction (HER). This catalyst, Ni‐H2‐2 %, was optimized through pyrolysis of a Ni‐containing metal‐organic framework precursor under a mixed N2/H2 atmosphere, which yielded carbon‐supported Ni nanoparticles with different levels of strains. The Ni‐H2‐2 % catalyst has an optimal level of strain, which leads to an optimal hydrogen binding energy and a high number of active sites.

Inter-regulated d-band centers of the Ni3B/Ni heterostructure for boosting hydrogen electrooxidation in alkaline media

“…3d, Tables S2 and S3 †). [16][17][18][19][20]22,24,[38][39][40][41] The exchange current densities (j 0 ) on these Ni-based catalysts could be further extracted by tting the kinetic current densities according to the Butler-Volmer equation (Fig. 3c).…”

“…S11 †) ), respectively, and is even comparable to those of some Pd-based catalysts (Tables S2 and S3 †). 10,[16][17][18][19][20]24,[38][39][40][41][42][43] In order to avoid the contribution from non-faradaic current, a steady-state polarization curve was also obtained for comparison to separate the hydrogen electrocatalytic response as shown in Fig. S12.…”

Engineering the Near‐Surface of PtRu3 Nanoparticles to Improve Hydrogen Oxidation Activity in Alkaline Electrolyte

“…These small variations in the d‐spacing values nevertheless validate the presence of a lattice strain effect of these catalysts, which can affect the surface electronic properties of nanocatalysts. [ 23 ] Highly dispersive PtRu 3 /PC alloy nanocatalysts can provide a larger surface area and a higher atom utility, which is very important for electrocatalytic reactions.…”

“…As expected, the binding energy of the three alloys produces a positive shift relative to the Pt itself, which indicates the downward shift of the Pt d‐band center, and the decrease of an electron back‐donation from the Pt 5d orbital to the 2p* orbital of CO, thus weakening the CO‐Pt bonding and the adsorption of the H species. [ 23,29 ] Moreover, the near‐surface atomic distribution will have a great impact on electronic structure, and the magnitude of the electronic effect is Pt‐increased < PtRu 3 /PC‐300 < Ru‐increased. According to the measured relative peak areas, the percentage of near‐surface metallic Pt for PtRu 3 /PC‐300, Pt‐increased, and Ru‐increased samples is 64.7%, 66.8%, and 61.4%, respectively, in which metallic Pt is the most significant active site to the H‐H cleavage.…”

Design Strategies of Transition‐Metal Phosphate and Phosphonate Electrocatalysts for Energy‐Related Reactions

“…In this respect, electrochemical energy conversion and storage technologies have shown great potential for developing next‐generation advanced energy systems. For example, hydrogen oxygen fuel cells can directly convert chemical energy into electrical energy using hydrogen at anode for hydrogen oxidation reaction (HOR) and oxygen at cathode for the oxygen reduction reaction (ORR) [1] . Rechargeable metal‐air batteries can be driven by the oxygen evolution reaction (OER) and ORR [2] .…”