Molecular Ions Research Articles

Efficient Control of Electron Localization and Probability Modulation with Synthesized Two-Color Intense Laser Pulses.

A coupled electron-nuclear dynamical study at attosecond time scale is performed on the HD+ and H2+ molecular ions under the influence of synthesized intense two-color electric fields. We have employed ω - 2ω and also, ω - 3ω two-color fields in the infrared/mid-infrared regime to study the different fragmentation processes originating from the interference of n - (n + i) (i = 1, 2) photon absorption pathways. The branching ratios corresponding to different photofragments are controlled by tuning the relative phase as well as intensity of the two-color pulses, while the effect of the initial nuclear wave function is also studied by taking an individual vibrational eigenstate or a coherent superposition of several eigenstates of HD+ and H2+. By comprehensive analysis, the efficacy of the two different types of synthesized two-color pulses (ω - 2ω and ω - 3ω) are analyzed with respect to one-color intense pulses in terms of controlling the probability modulation and electron localization asymmetry and compared with previous theoretical calculations and experimental findings. Through the detailed investigation, we have addressed which one is the major controlling knob to have better electron localization as well as probability modulation.

Organometallic Ionic Plastic Crystals Incorporating Cationic Half-Sandwich Complexes.

Ionic plastic crystals (IPCs), characterized by nearly spherical molecular ions, exhibit remarkable solid-state characteristics including high ionic conductivity. However, most IPCs are organic onium salts. Incorporating organometallic half-sandwich complexes into IPCs is challenging owing to their low-symmetry structures. This paper introduces a novel series of IPCs composed of salts derived from half-sandwich organometallic complexes. We synthesized five salts of [Ru(Cp)(tmeda)(CO)]X (tmeda = N,N,N',N'-tetramethyl-1,2-ethanediamine, X = anion) with different anions and examined their phase behavior, crystal structures, and molecular motion in the solid-state. Salts featuring the CPFSA (= 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide), B(CN)4-, and FSA- (= (FSO2)2N-) anions underwent phase transitions to an IPC phase with a CsCl-type structure in the temperature range of 327-364 K. Employing smaller anions led to an increase in the transition temperature. In each salt, the coordination number, representing the number of anions surrounding one cation, remained eight in IPC and low-temperature phases. However, salts containing smaller anions (CF3BF3- and PF6-) displayed a rotator phase rather than the IPC phase. In these cases, the coordination numbers were six at low temperatures.

Cool Classical EI - A New Standard in EI and Its Many Benefits.

GC-MS with Cold EI improves all of the central GC-MS performance aspects, but it is known mostly for its provision of enhanced molecular ions. This occasionally leads to the misconception that, like chemical ionization, Cold EI is a supplementary ion source to standard EI. However, Cold EI is a highly superior replacement ion source to standard EI. While Cold EI mass spectra are the most informative and fully compatible with mass spectral library (such as NIST) identification, in some cases, the Cold EI mass spectra with their enhanced molecular ions result in a "picture" that is not as one is used to seeing. In this paper, we describe the "Cool Classical EI" mode, which produces classical EI mass spectra like standard EI. The change of Cold EI into the Cool Classical EI mode is software-based, requires no hardware change, and can be achieved even during the analysis. Several mass spectra that were obtained in the Cool Classical EI mode are presented and compared with standard EI and Cold EI mass spectra. In this paper we further demonstrate and discuss several benefits that Cold EI brings that are retained while using Cool Classical EI, including (a) much faster speed of analysis, (b) uniform response, (c) extended range of compounds amenable for analysis, (d) improved sample identification, (e) elimination of ion source related peak tailing, (f) elimination of intraion-source degradation, and (g) better signal-to-noise ratio of the sample compounds.

Synthesis, characterization, DFT and docking studies of tributyltin(IV) complex of 2-{4-hydroxy-3-[(2-carboxyphenylimino)methyl]phenylazo} benzoic acid

A tributyltin(IV) complex was prepared by reacting bis-tributyltin(IV) oxide with 2-{4-hydroxy-3-[(2-carboxyphenylimino)methyl]phenylazo}benzoic acid in a 1:1 metal-ligand ratio. The complex was characterized by elemental analysis, UV-Vis, IR,1H and 119Sn NMR spectroscopy and mass spectrometry techniques. The 119Sn NMR study of the complex indicated the presence of two tin centers in a similar chemical environment and the complex exhibited a five-coordinate trigonal bipyramidal geometry in the solution phase. The molecular ion peak in the EI-MS spectrum of the complex revealed its molar mass. The optimized geometry of the complex was predicted by a DFT calculation. The in vitro antifungal activity of the complex was studied against four fungal species with respect to the standard drug Amphotericin-B. A molecular docking study was also carried out to understand the mode of interaction of the complex with the active side of the enzyme present in fungal species.

Low-energy atomic and molecular hydrogen ion interaction with low-work function electride 12CaO · 7Al2O3

To efficiently generate H− ions from positive atomic or molecular hydrogen beams injected onto a solid surface, it has been suggested to use a material with a low-work function as the target material. However, it is not clear under what conditions the most efficient H− production is realized for incident beam parameters or reflection angles. Therefore, we studied the interaction between low-energy atomic and molecular hydrogen beams (less than 1 keV/nucleon) with a low-work function electride 12CaO⋅7Al2O3 (C12A7). The production ratio of H− to H+ ions from the C12A7 electride was much higher than Mo targets with higher work functions, especially at smaller incident and smaller reflection angles. The H− to H+ production ratio slightly increased as the incident energies were decreased, but there was no significant difference between the electride and Mo targets. These results indicate that smaller incident angles and lower beam energies of the incident hydrogen beam are favorable for the enhancement of the production ratio of H− to H+ ions in C12A7. The higher production ratio appeared at the vertical beam energies less than on the order of 100 eV, where quantum mechanical processes may become important.

In situ measurement of electron emission yield at Si and SiO2 surfaces exposed to Ar/CF4 plasmas

Abstract Plasma simulations require accurate yield data to predict the electron flux that is emitted when plasma-exposed surfaces are bombarded by energetic particles. One can measure yields directly using particle beams, but it is impractical to create a separate beam of each particle produced by typical plasmas. In contrast, measurements made in situ, during plasma exposure, provide useful values for the total emitted flux and effective yield produced by all incident particles. Here, in situ measurements were made at thermally oxidized and bare silicon wafers placed on the radio-frequency (rf) biased electrode of an inductively coupled plasma (icp) system. The rf current and voltage across the sheath at the wafer were measured, along with Langmuir probe measurements of ion current density and electron temperature. The measurements are input into a numerical sheath model, which allows the emitted electron current to be distinguished from other currents. The effective yield, i.e., the ratio of the total emitted electron flux to the incident ion flux, was determined at incident ion energies from 40 eV to 1.4 keV, for Si and SiO2 surfaces in Ar, CF4, and Ar/CF4 mixtures at 1.33 Pa (10 mTorr). Yields for Ar plasmas are compared with previous work. For SiO2 surfaces in Ar/CF4 mixtures and pure CF4, the yield is dominated by ion kinetic emission, which is the same for all mixtures, and, presumably, for all ions. For SiO2 surfaces in Ar/CF4 and CF4, the yield at high energies can be explained in part by fragmentation of molecular ions, and the yield from Ar+ can be distinguished from the other ionic species. Analytic fits of the yields are provided for use in plasma simulations.

Photodissociation spectra of single trapped CaOH+ molecular ions.

Molecular ions that are generated by chemical reactions with trapped atomic ions can serve as an accessible testbed for developing molecular quantum technologies. On the other hand, they are also a hindrance to scaling up quantum computers based on atomic ions, as unavoidable reactions with background gases destroy the information carriers. Here, we investigate the single- and two-photon dissociation processes of single CaOH+ molecular ions co-trapped in Ca+ ion crystals using a femtosecond laser system. We report the photodissociation cross section spectra of CaOH+ for single-photon processes at λ = 245-275 nm and for two-photon processes at λ = 500-540 nm. Measurements are interpreted with quantum-chemical calculations, which predict the photodissociation threshold for CaOH+ → Ca+ + OH at 265nm. This result can serve as a basis for dissociation-based spectroscopy for studying the internal structure of CaOH+. The result also gives a prescription for recycling Ca+ ions in large-scale trapped Ca+ quantum experiments from undesired CaOH+ ions formed in the presence of background water vapor.

Dissociative recombination of NS+ in collision with slow electrons

Cross sections and rate coefficients for the dissociative recombination (DR) of the NS+ ion induced by collisions with low-energy electrons are reported for temperatures between 10 and 1000 K, relevant to a large range of interstellar cloud temperatures. Uncertainties are discussed for these rates. Comparisons are made with DR rates for the isovalent NO+ molecular ion which are found to be much faster. The present findings lead to a moderate dissociative reaction rate coefficient, smaller by a factor of 2 than the current estimates reported in the different kinetic databases for a temperature of 10 K. We consider that our rate coefficients obtained through multichannel quantum defect theory for NS+ are likely to be better than those displayed in the different kinetic databases.

Peptides En Route from Prebiotic to Biotic Catalysis.

ConspectusIn the quest to understand prebiotic catalysis, different molecular entities, mainly minerals, metal ions, organic cofactors, and ribozymes, have been implied as key players. Of these, inorganic and organic cofactors have gained attention for their ability to catalyze a wide array of reactions central to modern metabolism and frequently participate in these reactions within modern enzymes. Nevertheless, bridging the gap between prebiotic and modern metabolism remains a fundamental question in the origins of life.In this Account, peptides are investigated as a potential bridge linking prebiotic catalysis by minerals/cofactors to enzymes that dominate modern life's chemical reactions. Before ribosomal synthesis emerged, peptides of random sequences were plausible on early Earth. This was made possible by different sources of amino acid delivery and synthesis, as well as their condensation under a variety of conditions. Early peptides and proteins probably exhibited distinct compositions, enriched in small aliphatic and acidic residues. An increase in abundance of amino acids with larger side chains and canonical basic groups was most likely dependent on the emergence of their more challenging (bio)synthesis. Pressing questions thus arise: how did this composition influence the early peptide properties, and to what extent could they contribute to early metabolism?Recent research from our group and colleagues shows that highly acidic peptides/proteins comprising only the presumably "early" amino acids are in fact competent at secondary structure formation and even possess adaptive folding characteristics such as spontaneous refoldability and chaperone independence to achieve soluble structures. Moreover, we showed that highly acidic proteins of presumably "early" composition can still bind RNA by utilizing metal ions as cofactors to bridge carboxylate and phosphoester functional groups. And finally, ancient organic cofactors were shown to be capable of binding to sequences from amino acids considered prebiotically plausible, supporting their folding properties and providing functional groups, which would nominate them as catalytic hubs of great prebiotic relevance.These findings underscore the biochemical plausibility of an early peptide/protein world devoid of more complex amino acids yet collaborating with other catalytic species. Drawing from the mechanistic properties of protein-cofactor catalysis, it is speculated here that the early peptide/protein-cofactor ensemble could facilitate a similar range of chemical reactions, albeit with lower catalytic rates. This hypothesis invites a systematic experimental test.Nonetheless, this Account does not exclude other scenarios of prebiotic-to-biotic catalysis or prioritize any specific pathways of prebiotic syntheses. The objective is to examine peptide availability, composition, and functional potential among the various factors involved in the emergence of early life.

QC-GN2oMS2: a Graph Neural Net for High Resolution Mass Spectra Prediction.

Predicting the mass spectrum of a molecular ion is often accomplished via three generalized approaches: rules-based methods for bond breaking, deep learning, or quantum chemical (QC) modeling. Rules-based approaches are often limited by the conditions for different chemical subspaces and perform poorly under chemical regimes with few defined rules. QC modeling is theoretically robust but requires significant amounts of computational time to produce a spectrum for a given target. Among deep learning techniques, graph neural networks (GNNs) have performed better than previous work with fingerprint-based neural networks in mass spectra prediction. To explore this technique further, we investigate the effects of including quantum chemically derived information as edge features in the GNN to increase predictive accuracy. The models we investigated include categorical bond order, bond force constants derived from extended tight-binding (xTB) quantum chemistry, and acyclic bond dissociation energies. We evaluated these models against a control GNN with no edge features in the input graphs. Bond dissociation enthalpies yielded the best improvement with a cosine similarity score of 0.462 relative to the baseline model (0.437). In this work we also apply dynamic graph attention which improves performance on benchmark problems and supports the inclusion of edge features. Between implementations, we investigate the nature of the molecular embedding for spectra prediction and discuss the recognition of fragment topographies in distinct chemistries for further development in tandem mass spectrometry prediction.

Plasma and gas neutralisation of high energy H- and D- in an Argon plasma neutraliser

A beam driven plasma neutraliser (BDPN) has been proposed [1] as a relatively simple way to increase the efficiency of neutral beam injectors based on the acceleration and neutralisation of H- or D-. Initial calculations showed that sufficient levels of ionisation could be achieved with H2 or D2 as the initial gas target in the neutraliser if a plasma confinement time of the plasma in the neutraliser is >0.5 ms could be achieved. However, later calculations [2,3] show that the afore-mentioned results were very optimistic as the calculations did not take into account the recombination of molecular ions with electrons. Hence, it has been suggested [4] to use an argon (Ar) plasma as the molecular ion content in such a plasma will be negligible. The use of an Ar plasma neutraliser has been suggested previously [5–7], but few details have been given of the obtainable neutralisation efficiency, the necessary line density for that neutralisation efficiency, or of the calculations and cross sections used to deduce those quantities. This paper briefly discusses why Ar could be a good choice for a plasma neutraliser, then the reactions occurring between the H-/D- beam and the particles in the Ar plasma, and the available cross section data for those reactions. Subsequently, the differential equations for the change of the species in the beam as it traverses an Ar plasma are deduced and solved, and the solutions used to calculate the achievable neutralisation efficiency as a function of the line density in the neutraliser etc. Results are given of the neutralisation efficiency as a function of the degree of ionisation in the neutraliser, the required line density, and the species changes in the beam for accelerated H- beams with 100, 500 and 870 keV energies.

Electric field-induced electronic structure and intersubband transitions of a hydrogen molecular ion in a gaussian-type quantum ring

In this work, the influence of an external electric field on the electronic structure and intersubband transitions of a singly ionized double-donor system in a GaAs quantum ring defined by Gaussian-type potentials is investigated theoretically. Within the framework of the effective mass approach, the two-dimensional diagonalization method is used for the solution of the Schrödinger equation to obtain the eigen energies and corresponding wave functions. Numerical results reveal that the electronic energy spectrum and the linear optical absorption coefficient of the ring are remarkably affected by the strength of the lateral electric field, internuclear distance and parameters defining the confinement potential. Also, it has been shown that beyond the anti-crossing point, the wave functions exchange their symmetries without mixing, which is a characteristic feature of energy-level anti-crossing.

UPLC-LTQ-Orbitrap Study on Rat Urinary Metabolites of 5-Methoxy-Alpha-Methyltryptamine.

5-Methoxy-α-Methyltryptamine (5-MeO-AMT) is a new psychoactive substance which is abused due to its hallucinogenic and euphoric effects. This study aimed to study the metabolic characteristics of 5-MeO-AMT. Five rats were given intraperitoneal injection at a dose of 50 mg/kg of 5-MeO-AMT, and their urine was subsequently collected at different times within 7 days. Ultra-high performance liquid chromatography-- tandem high-resolution mass spectrometry (UPLC-LTQ-Orbitrap) was used to detect the precise molecular weight and fragment ions of 5-MeO-AMT and its possible metabolites in the urine sample extracted with benzene-ethyl acetate. Three metabolites, including OH-5-MeO-AMT, α-Me-5-HT, and N-Acetyl-5-MeO-AMT were identified in rats' urine. The major metabolic pathways involved O-demethylation, hydroxylation of indole ring, and Acetylation on aliphatic amines. The results of this study are an important reference for the identification and screening of toxicants of 5-MeO-AMT.

Discovery of Unprecedented Human Stercobilin Conjugates.

Two unique metabolites (M18 & M19) were detected in feces of human volunteers dosed orally with [14C]inavolisib with a molecular ion of parent plus 304 Da. They were generated in vitro by incubation with fecal homogenates and we have evidence that they are formed chemically and possibly enzymatically. Structural elucidation by high resolution mass spectrometry and NMR spectroscopy showed that the imidazole ring of inavolisib was covalently bound to partial structures derived from stercobilin, an end-product of heme catabolism produced by the gut microbiome. The structural difference between the two metabolites was the position of methyl and ethyl groups on the pyrrolidin-2-one moieties. We propose a mechanism of M18 and M19 generation from inavolisib and stercobilin whereby nucleophilic attack from the imidazole ring of inavolisib occurs to the bridging carbon of a stercobilin molecule. The proposed mechanism was supported by computational calculations of molecular orbitals and transition geometry. Significance Statement We report the characterization of two previously undescribed conjugates of the PI3K inhibitor inavolisib, generated by reaction with stercobilin, an end-product of heme catabolism produced by gut microbiome. These conjugates were confirmed by generating them using in vitro fecal homogenate incubation via non-enzymatic and possibly enzymatic reactions. Given the unique nature of the conjugate, it is plausible that it may have been overlooked with other small molecule drugs in prior studies.

Rapid analysis of untreated food samples by gel loading tip spray ionization mass spectrometry.

Rapid, efficient, versatile, easy-to-use, and non-expensive analytical approaches are globally demanded for food analysis. Many ambient ionization approaches based on electrospray ionization (ESI) have been developed recently for the rapid molecular characterization of food products. However, those approaches mainly suffer from insufficient signal duration for comprehensive chemical characterization by tandem MS analysis. Here, a commercially available disposable gel loading tip is used as a low-cost emitter for the direct ionization of untreated food samples. The most important advantages of our approach include high stability, and durability of the signal (> 10min), low cost (ca. 0.1 USD per run), low sample and solvent consumption, prevention of tip clogging and discharge, operational simplicity, and potential for automation. Quantitative analysis of sulfapyridine, HMF (hydroxymethylfurfural), and chloramphenicol in real sample shows the limit-of-detection 0.1μgmL-1, 0.005μgmL-1, 0.01μgmL-1; the linearity range 0.1-5μgmL-1, 0.005-0.25μgmL-1, 0.01-1μgmL-1; and the linear fits R2 ≥ 0.980, 0.991, 0.986. Moreover, we show that tip-ESI can also afford sequential molecular ionization of untreated viscous samples, which is difficult to achieve by conventional ESI. We conclude that tip-ESI-MS is a versatile analytical approach for the rapid chemical analysis of untreated food samples.

Rapid analysis of untreated food samples by gel loading tip spray ionization mass spectrometry.

Rapid, efficient, versatile, easy-to-use, and non-expensive analytical approaches are globally demanded for food analysis. Many ambient ionization approaches based on electrospray ionization (ESI) have been developed recently for the rapid molecular characterization of food products. However, those approaches mainly suffer from insufficient signal duration for comprehensive chemical characterization by tandem MS analysis. Here, a commercially available disposable gel loading tip is used as a low-cost emitter for the direct ionization of untreated food samples. The most important advantages of our approach include high stability, and durability of the signal (> 10min), low cost (ca. 0.1 USD per run), low sample and solvent consumption, prevention of tip clogging and discharge, operational simplicity, and potential for automation. Quantitative analysis of sulfapyridine, HMF (hydroxymethylfurfural), and chloramphenicol in real sample shows the limit-of-detection 0.1μgmL-1, 0.005μgmL-1, 0.01μgmL-1; the linearity range 0.1-5μgmL-1, 0.005-0.25μgmL-1, 0.01-1μgmL-1; and the linear fits R2 ≥ 0.980, 0.991, 0.986. Moreover, we show that tip-ESI can also afford sequential molecular ionization of untreated viscous samples, which is difficult to achieve by conventional ESI. We conclude that tip-ESI-MS is a versatile analytical approach for the rapid chemical analysis of untreated food samples.

A new 915 MHz coaxial-line-based microwave plasma source

Microwave plasma is known for its versatility in providing tailored operating conditions (pressure, working gas composition and residence time of reagents) for specific applications. Microwave plasma sources (MPSs) are vital in modern applications, demanding continuous improvement. This work introduces a coaxial-line-based nozzleless MPS that operates at atmospheric pressure at an unique frequency of 915 MHz. The measured electrodynamic characteristics in nitrogen of the MPS highlighted the need for improved energy efficiency of the device. The main novelty of this work lies in improving an energy efficiency of the presented MPS, which led to an advanced new version of the device. To achieve this, a dual strategy is employed. Firstly, numerical simulations are used to design a construction modifications to the MPS, which should increase the efficiency of transferring microwave energy from the microwave source to the generated plasma. In this step, a standard model for homogeneous plasma and a two-port equivalent method were used. Then, the theoretical results were experimentally validated by manufacturing a new energy improved version of the MPS. In the new MPS the achieved reflected microwave power (losses) was less than 3% of incident microwave power in the tested range of nitrogen flow rate (50–100 Nl/min). Compared to the MPS before improvement, this means a two-fold decreasing the reflected microwave power. To test the new MPS, the electrodynamic characteristics of the new device version and properties of the microwave plasma generated in nitrogen, using optical emission spectroscopy (OES), were investigated. The OES was used to determine the vibrational Tvib and rotational Trot temperatures of nitrogen molecules and molecular ions. In this work, the estimated Tvib and Trot temperatures for nitrogen molecules ranged from 4000 to 5300 K, depending on discharge conditions, while for nitrogen molecular ions, the temperatures changed between 4700 and 6100 K, respectively. Both the Tvib and Trot temperatures decrease linearly along the plasma flame.

Magnetic ligand fishing protocol combined with HPLC-FT-ICR-MS for screening potential α-Glucosidase inhibitors from UCG and in silico analysis

Uremic Clearance Granule (UCG) is a traditional Chinese medicines (TCMs) that has been recognized as potentially effective treatment for diabetic nephropathy (DN). However, the chemical composition and the hypoglycemic ingredients of UCG remain unclear. In this experiment, a magnetic ligand fishing protocol combined with HPLC coupled Fourier transform ion cyclotron resonance mass spectrometry (HPLC-FT-ICR-MS) technology was developed to screen and identify α-Glucosidase inhibitors from UCG. First, constituents of UCG was identified by HPLC-FT-ICR-MS. Next, α-Glucosidase coated Fe3O4@SiO2@NH2 (Fe3O4@SiO2@NH2@α-Glucosidase) nano composites was synthesized. The essential parameters (concentration of Glutaraldehyde (GA), ratio of Fe3O4@SiO2@NH2 to enzyme, crosslinking time and immobilization time) were optimized to obtain maximum enzyme activity and the performance of immobilized enzyme was compared with that of free enzyme. The α-Glucosidase inhibitory activities were then evaluated using autodock and the 4-Nitrophenyl-α-D-glucopyranoside (pNPG) method. As a result, 142 compounds were identified were identified by comparing the retention time, molecular ions and fragmentation behaviors with the reference compounds or the in-house database. 20 possible α-Glucosidase activity inhibitory components were identified using HPLC-FT-ICR-MS. Molecular docking and inhibition studies showed that 4 compuunds including Limonexic acid, Sanggenol A, Glabrone, Matrine were more likely to stronger α-Glucosidase inhibitory activities than acarbose. In conclusion, the proposed approach, which combined highly specific screening with HPLC-FT-ICR-MS, provided a powerful platform for discovering bioactive components from multi-component and multi-target traditional Chinese medicines (TCMs).

Deciphering the uranium isotopic signature of coastal water and sediments from Tokyo Bay using a multi-collector inductively coupled plasma mass spectrometer

We have measured 236U/238U and 235U/238U values in JMS-1 (geochemical reference material of Tokyo Bay sediments) and coastal seawater using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) equipped with both the retarding potential quadrupole lens and desolvating nebuliser system. For the accurate measurement of 236U/238U values (e.g., in the range of 10−9), mass spectrometric interferences on 236U isotope from both the peak tailing of 238U and polyatomic ion of 235UH were carefully corrected. With the sequential extraction experiments for JMS-1, whose U isotopic signatures were characteristic of isotopically-depleted U with industrial uses, authigenic U was extracted into a soluble fraction, and lithogenic U and anthropogenic U were gathered in an insoluble fraction. The anthropogenic U is likely to have been provided in insoluble forms and have deposited on the bay floor. Absence in differences of 236U/238U and 235U/238U values for seawater observed between inside and outside Tokyo Bay implies the negligibly small contribution of the anthropogenic U to U in the seawater. The data obtained here demonstrate the effective reduction of the interferences on 236U and the versatility of the isotopic signatures of U as an effective tracer for environmental circulation of U in nature.

Operando-reconstructed polyatomic ion layers boost the activity and stability of industrial current–density water splitting

Metal–organic frameworks have garnered attention as highly efficient pre-electrocatalysts for the oxygen evolution reaction (OER). Current structure–activity relationships primarily rely on the assumption that the complete dissolution of organic ligands occurs during electrocatalysis. Herein, modeling based on NiFe Prussian blue analogs (NiFe-PBAs) show that cyanide ligands leach from the matrix and subsequently oxidize to corresponding inorganic ions (ammonium and carbonate) that re-adsorb onto the surface of NiFe OOH during the OER process. Interestingly, the surface-adsorbed inorganic ions induce the OER reaction of NiFe OOH to switch from the adsorbate evolution to the lattice-oxygen–mediated mechanism, thus contributing to the high activity. In addition, this reconstructed inorganic ion layer acting as a versatile protective layer can prevent the dissolution of metal sites to maintain contact between catalytic sites and reactive ions, thus breaking the activity–stability trade-off. Consequently, our constructed NiFe-PBAs exhibit excellent durability for 1250 h with an ultralow overpotential of 253 mV at 100 mA cm−2. The scale-up NiFe-PBAs operated with a low energy consumption of ∼4.18 kWh m−3 H2 in industrial water electrolysis equipment. The economic analysis of the entire life cycle demonstrates that this green hydrogen production is priced at US$2.59/kgH2, meeting global targets (<US$2.5/kgH2).