Crystallographic facet selective HER catalysis: exemplified in FeP and NiP₂ single crystals

Abstract

The effect of the crystal structure of ordered transition-metal phosphide catalysts on the hydrogen-evolution reaction is investigated using single crystals of iron-phosphide (FeP) and monoclinic nickel-diphosphide (m-NiP2).

New Opportunity for Carbon‐Supported Ni‐based Electrocatalysts: Gas‐Phase CO2 Methanation

“…The lower energy component (852.7 eV) is assigned to Ni 0 in metallic Ni species, while the components at 853.9±0.2 eV and 855.8±0.2 eV are consistent with Ni 2+ in nickel oxide phase, and the ones at 861.1±0.3 eV and 863.6±0.4 eV are satellite peaks from Ni 2+ [30] . The presence of multiple components in the 851–858 eV BE range is typical for nanoscale oxidation layers on Ni and Ni compounds [9,30,31] with the combination of three main components at ca. 852.7, 853.9, and 855.8 eV in Figure 3a–c, being most consistent with a thin, predominantly Ni 2+ , nickel oxide layer on metallic Ni.…”

Phase‐Junction Electrocatalysts towards Enhanced Hydrogen Evolution Reaction in Alkaline Media

“…853.4 eV), respectively (Figure 2 g). [29] The peak at about 857.1 eV in Ni 2p 3/2 spectra belonged to NiO, [30] and the NiO peaks were also observed in O 1s spectra (Supporting Information, Figure S6), which originated from the partial surface oxidation in atmosphere [20b] . For P 2p spectra (Figure 2 h), the P 2p 1/2 and P 2p 3/2 peaks for c ‐NiP 2 were located at 129.08 eV and 129.98 eV, respectively, while for m ‐NiP 2 , they positively shifted to about 129.8 eV and about 130.6 eV (Figure 2 h), respectively, which might be cause by the transfer of electrons from P atom to Ni atom [20a] .…”

“…[19] By contrast, monoclinic NiP 2 has layers of tilted vertex-shared Ni@P 4 squares (m-NiP 2 ;S upporting Information, Figure S1b) with semiconductor characteristic and higher electrical resistivity. [20] Compared with c-NiP 2 , m-NiP 2 has fewer NiÀPb onds, resulting in relatively lower catalytic activity. [21] Owing to the different band structures,the energy-level alignment at the c-NiP 2 /m-NiP 2 interface may effectively promote electron transfer from m-NiP 2 to c-NiP 2 .…”

New Noncentrosymmetric Tetrel Pnictides Composed of Square‐Planar Gold(I) with Peculiar Bonding

“…[14] In AuSiP,S ia nd Pf orm puckered ordered hexagonal layers,c onnected by linearly coordinatedA u atoms( Figure 1). Ad ifferent centrosymmetric structure, NiP 2 type, [15][16][17] was proposed for AuGeAs based on thin-film studies. [18] Such structurald etermination is challengingb ecause of the inability to distinguish Ge from As, due to similarities in their X-ray scattering factors.…”