Synthesis, Crystal Structure, Electronic Structure, and Electrocatalytic Hydrogen Evolution Reaction of Synthetic Perryite Mineral

Abstract

Recently, it has been reported that the enstatite chondrite (EC) meteorite may contain enough hydrogen to provide a plausible explanation for water’s initial existence on Earth. Perryite mineral is one of the key components of EC, but its detailed chemical composition and phase width remain elusive compared with other minerals found in EC. Therefore, we embark on a series of investigations of the synthesis, crystal structure, and electronic structure of the synthetic perryite mineral (Ni x Fe1–x )8(T y P1–y )3 (T = Si and Ge; 1 ≥ x, y ≥ 0). Its crystal structures were established based on single-crystal and powder X-ray diffraction techniques. It is realized that its structural and phase stabilities are highly dependent on the nature of the doping element (i.e., Fe and Si). The inclusion of Si and Fe elements can greatly alter the bonding scheme near the Fermi level (E f), which is vital to the phase stability and accounts for the chemical composition of the natural perryite mineral (quaternary compound) in EC meteorites. Furthermore, this phase exhibits good electrocatalytic activity toward the hydrogen evolution reaction (HER). The best and the worst HER performances are for the Ni8Ge2P and Ni8Si2P samples, respectively, which suggests that the long bond length and high polarity of the covalent bond are the preferred criteria to enhance the electrocatalytic HER in this series.

Crystal and Electronic Structure Modification of Synthetic Perryite Minerals: A Facile Phase Transformation Strategy to Boost the Oxygen Evolution Reaction

“…As shown in the inset of Figure , the peak of Ni 2p 1/2 for Ni 8 GeP 2 moves slightly to the right than that of Ni 8 Si 1.5 P 1.5 . This suggests a more partial positive charge of the Ni metallic state in the Ge analogue, which is most likely due to the higher electronegativity of Ge compared to that of Si (χ Ge = 2.01; χ Si = 1.9) . In the samples with Fe inclusion, Ni 7 FeGeP 2 and Ni 7 FeSi 1.5 P 1.5 , the situation for the partial positive charge of Ni metallic states becomes more obvious than that in the Fe-free ones.…”

“…The unit cell parameters for building models of Ni 8 GeP 2 , Ni 8 Ge 1.5 P 1.5 , Ni 8 Ge 2 P, and Ni 7 FeGeP 2 were acquired from PXRD refinement (Table S1). The atomic sites for Ge and Fe inclusion in these models follow our previous report and a succinct description was given herein . In the pristine Ni 8 P 3 model, there are seven independent sites in the asymmetric unit, where four sites are for Ni atoms and three sites are for P atoms.…”

“…The chemical composition found in natural perryite mineral (Ni: 82.9; Fe: 1.84; Si: 11.1; and P: 4.28) turns out to be quite suitable to implement electrocatalytic OER. Our group has recently unveiled the chemical composition, crystal structure, and electronic structure of the synthetic perryite phase . It was realized that Si in the perryite phase can be replaced with a larger Ge element and the Ni-to-Fe ratio is adjustable in the perryite phase.…”

Exploring the synergistic effect of alloying toward hydrogen evolution reaction: a case study of Ni3M (M = Ti, Ge and Sn) series

“…The JADE program was employed to refine the diffraction pattern of each sample. 16 The refined lattice constants and interatomic distances are tabulated in Table S1 †. The simulated and experimental powder XRD patterns along with their difference plot are shown in Fig.…”

Function of Doping Ru Element in the Hydrogen Evolution Reaction in Rare-Earth Transition-Metal Intermetallics

“…For instance, one can grow these TM-based electrocatalysts on three-dimensional substrates such as metal foam or carbon cloth to increase the electrochemical surface area (ECSA) or roughness factor (RF). , In contrast to the change of extrinsic property (e.g., active surface area), one can alter the electronic structure of TM-based electrocatalysts and adjust the corresponding hydrogen adsorption energy to promote the HER activity intrinsically . The most typical and straightforward technique to alter the electronic structure is to introduce a foreign element in the structure (i.e., by doping). , This can induce ligand effect (i.e., charge transfer) owing to the different electronegativity of each element in the samples, which many alloys or intermetallic systems (e.g., Ti x Cu 1– x , Ru x Co 1– x , and MoNi 4 ) demonstrate strong synergistic effect and exhibit superior HER activity compared to that of individual elements.…”