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

Abstract

Ni3B/Ni heterostructures with optimized hydrogen/hydroxyl binding energies have been constructed for effective alkaline hydrogen oxidation electrocatalysis.

Modification of the Intermediate Binding Energies on Ni/Ni3N Heterostructure for Enhanced Alkaline Hydrogen Oxidation Reaction

“…[36] For comparison, as shown in Figure S4, Supporting Information, the binding energy (BE) of metallic Ni in Ni 3 NC (853.3 eV) is higher than that in NiC (852.4 eV), which is possibly due to electron transfer from Ni to N in Ni 3 NC, induced by their different electronegativities. In particular, the BE of Ni species in Ni/Ni 3 NC is higher than that in NiC, but lower than that [35] Meanwhile, as shown in the high-resolution N 1s XPS spectrum of Ni/Ni 3 NC, the peak located at ≈398.1 eV can be ascribed to the NiN bond (Figure S4c, Supporting Information). [28,37] Furthermore, the BE of N species in Ni 3 NC displays a negative shift in contrast to that in Ni/Ni 3 NC (Figure 2c), further suggesting the charge transfer between the Ni/Ni 3 N interface.…”

“…The high-resolution TEM (HRTEM) image shown in Figure 1d indicates the existence of two-phase interface in Ni/Ni 3 NC. [34,35] The interfacial lattice fringes with interplanar spacings of 0.177 and 0.213 nm can be assigned to the (200) plane of fcc Ni and (002) plane of hcp Ni 3 N (Figure 1e,f), respectively. [20,21] Moreover, high-angle annular dark-field scanning TEM (HAADF-STEM)-energy dispersive X-ray mapping further confirm the existence of Ni and N elements in Ni/Ni 3 N heterostructure catalyst (Figure 1g).…”

“…Their anodic CV curves in Figure S5, Supporting Information, show that the peak of Ni/Ni 3 NC is negatively shifted and positively shifted compared to that of NiC and Ni 3 NC, respectively, indicating electron rearrangement in the heterostructure electrocatalyst, in consistent with XPS result (Figure 2b). [18,35] The HOR polarization curves in Figure 3a, measured in H 2 -saturated solution with a rotation rate of 2500 revolutions per minute (rpm) at a scan rate of 5 mV s −1 , indicate Ni/Ni 3 NC possesses the highest apparent HOR activity among these catalysts. Specifically, HOR polarization curves of NiC, Ni/Ni 3 NC, and Ni 3 NC at various rotating rates from 2500 to 400 rpm were recorded in Figure S6a,c,e, respectively, Supporting Information.…”

“…Their Koutecky-Levich plots (Figure S6b,d,f, Supporting Information) with a slope (1/Bc 0 ) of 14.93, 14.44, and 13.67 cm 2 mA −1 rpm 1/2 (close to the theoretical value) could be constructed at the overpotential of 50 mV, respectively. [14,35] Correspondingly, the kinetic current densities (j k ) without interference of mass transfer of H 2 can be obtained according to the Koutecky-Levich equation. [14] Additionally, the metal loadings of these electrocatalysts can be obtained by the inductively coupled plasma atomic emission spectroscopy results (Table S1, Supporting Information).…”

High-Performance Ru 2 P Anodic Catalyst for Alkaline Polymer Electrolyte Fuel Cells

“…Proton-exchange membrane fuel cells (PEMFCs) are regarded as the most significant renewable energy conversion technology for efficiently accomplishing transformation from hydrogen to electrical energy, which involves anodic the hydrogen oxidation reaction (HOR), as well as the cathodic oxygen reduction reactions (ORRs). [1][2][3] Currently, Pt remains the most advanced ORR electrocatalyst for PEMFCs, but its use is limited by its high cost and scarcity. 4,5 Due to their harsh acidic environment, most nonnoble metals and their alloys are labile and hence lead to low durability in PEMFCs.…”