Hydrogen Adsorption Energy Research Articles

Atomic Adsorption Energies Prediction on Bimetallic Transition Metal Surfaces Using an Interpretable Machine Learning-Accelerated Density Functional Theory Approach.

In this study, we identified features with the largest contributions and property trends in predicting the adsorption energies of carbon, hydrogen, and oxygen adsorbates on transition metal (TM) surfaces by performing Density Functional Theory (DFT)-based calculations and Machine Learning (ML) regression models. From 26 monometallic and 400 bimetallic fcc(111) TM surfaces obtained from Catalysis-hub.org, three datasets consisting of fourteen elemental, electronic, and structural properties were generated using DFT calculations, site calculations, and online databases. The number of features was reduced using feature selection and then finely-tuned random forest regression (RFR), gaussian process regression (GPR), and artificial neural network (ANN) algorithms were implemented for adsorption energy prediction. Finally, model-agnostic interpretation methods such as permutation feature importance (PFI) and shapely additive explanations (SHAP) provided rankings of feature contributions and directional trends. For all datasets, RFR and GPR demonstrated the highest prediction accuracies. In addition, interpretation methods demonstrated that the largest contributing features and directional trends in the regression models were consistent with structure-property-performance relationships of TMs like the d-band model, the Friedel model, and higher-fold adsorption sites. Overall, this interpretable ML-DFT approach can be applied to TMs and their derivatives for atomic adsorption energy prediction and model explainability.

Design a functional graphene with decoration of dual transition metal dopants for hydrogen evolution electrocatalysis.

Since hydrogen is a promising alternative to fossil fuels due to its high energy density and environmental friendliness, water electrolysis for hydrogen production has received widespread attentions wherein the development of active and stable catalytic materials is a key research direction. This article designs a dual transition metal doped functional graphene for hydrogen evolution reaction via density functional theory calculations. Among varied combinations, 16 candidates are screened out that are expected to be stable as reflected by the criterion of formation energy Ef < 0 and active due to its free energy of hydrogen adsorption ∆GH within the window of ±0.3 eV. Considering its feasibility in structural modification and electronic adjustment due to the strong dd orbital couplings, the homogeneous dual-atom moiety delivers improved performance toward hydrogen evolution in comparison with the single-atom counterpart. Owing to the good resistance of electrochemical dissolution, the work figures out the potential combinations of Cu2C3N3, Rh2C6, Rh2C3N3 and Rh2N6 endowed with the ∆GH values of -0.03, 0.12, -0.21, and 0.06 eV, respectively, being comparable to the benchmark Pt materials. Therefore, this study provides a new direction for the experimental synthesis of highly active carbon-based electrocatalysts and highlights the well-tuning ability posed by dual-atom interaction.

Strain Engineering of Ru–Co2Ni Nanoalloy Encapsulated with Carbon Nanotubes for Efficient Anion and Proton Exchange Membrane Water Electrolysis

AbstractAlloying atomically dispersed noble metals with earth‐abundant transition metal nanoparticles (NPs) presents a promising approach to enhance the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water electrolysis. However, the challenge remains of reducing the size of the NPs without sacrificing high activity and durability. In this study, Ru–Co2Ni nanoalloy particles (NAPs) encapsulated in nitrogen‐doped carbon nanotubes (NCNTs) are introduced, forming a core‐shell electrocatalyst (Ru–Co2Ni@NCNT). This design leverages Ru site optimization, CNT density control, strain engineering, efficient water dissociation, and outstanding bubble release dynamics within the core‐shell structure. These factors significantly improve catalytic performance with low overpotentials of 35 and 57 mV overpotential in 1.0 m KOH and 0.5 m H2SO4 solutions, respectively, at a current density of 10 mA cm−2. Density functional theory (DFT) calculations reveal that while Ru sites serve as active sites, they also modify the electronic structure of Co and Ni, optimizing their hydrogen adsorption energies and improving HER efficiency. The Ru–Co2Ni@NCNT catalyst is successfully integrated into both anion exchange membrane (AEM) and proton exchange membrane (PEM) electrolyzers, demonstrating stable operation at 0.5 A cm−2 for 500 h, underscoring its potential for efficient and durable hydrogen production.

Fine-tunable N-doping in carbon-coated CoFe nano-cubes for efficient hydrogen evolution in AEM water electrolysis

To obtain environment-friendly and renewable hydrogen energy, research is being actively conducted towards lowering the hydrogen evolution reaction (HER) energy barrier through various modifications to the surface of a transition metal bimetal electrochemical catalyst. Herein, we report the development of highly N-doped carbon shell-encapsulated cobalt iron nano cube (CoFe@HNCS) through fine-tuning of the nitrogen-doping content in the carbon shell. The pyridinic N-rich N-doped carbon shell, achieved by adding melamine through electrostatic interactions, improves conductivity, increases active sites, and optimizes Gibbs free energy for hydrogen adsorption. In alkaline HER performance, the optimized CoFe@HNC20 exhibits a lower overpotential (98.2 mV) than CoFe@NCS (133.2 mV) at 10 mA cm−2. Furthermore, CoFe@HNCS20 as cathode catalyst in anion exchange membrane (AEM) water electrolyzer also shows low cell voltage of 1.808 V to achieve the current density of 0.5 A cm−2. The expansion of the application to combine solar cells and AEM electrolyzer suggests the possibility of a hydrogen ecosystem.

Atomic Gap-State Engineering of MoS2 for Alkaline Water and Seawater Splitting.

Transition-metal dichalcogenides (TMDs), such as molybdenum disulfide (MoS2), have emerged as a generation of nonprecious catalysts for the hydrogen evolution reaction (HER), largely due to their theoretical hydrogen adsorption energy close to that of platinum. However, efforts to activate the basal planes of TMDs have primarily centered around strategies such as introducing numerous atomic vacancies, creating vacancy-heteroatom complexes, or applying significant strain, especially for acidic media. These approaches, while potentially effective, present substantial challenges in practical large-scale deployment. Here, we report a gap-state engineering strategy for the controlled activation of S atom in MoS2 basal planes through metal single-atom doping, effectively tackling both efficiency and stability challenges in alkaline water and seawater splitting. A versatile synthetic methodology allows for the fabrication of a series of single-metal atom-doped MoS2 materials (M1/MoS2), featuring widely tunable densities with each dopant replacing a Mo site. Among these (Mn1, Fe1, Co1, and Ni1), Co1/MoS2 demonstrates outstanding HER performance in both alkaline and seawater alkaline media, with overpotentials at a mere 159 and 164 mV at 100 mA cm-2, and Tafel slopes at 41 and 45 mV dec-1, respectively, which surpasses all reported TMD-based nonprecious materials and benchmark Pt/C catalysts in HER efficiency and stability during seawater splitting, which can be attributed to an optimal gap-state modulation associated with sulfur atoms. Experimental data correlating doping density and dopant identity with HER performance, in conjunction with theoretical calculations, also reveal a descriptor linked to near-Fermi gap state modulation, corroborated by the observed increase in unoccupied S 3p states.

Mechanical Reversal in the Catalytic Capability of Monolayer Transition Metal Dichalcogenides for Hydrogen Evolution Reaction: An Explicit First-Principles Study.

Pristine transition metal dichalcogenide (TMD) monolayers are generally regarded as exhibiting low chemical reactivity due to their inert surfaces. Our extensive first-principles calculations, which incorporate an explicit solvation model, reveal that the catalytic performance of pristine TMD MX2 (where M = Mo or W, and X = S, Se or Te) monolayers for hydrogen evolution reaction can be significantly altered and enhanced through mechanically bending deformation. For a WTe2 monolayer, its hydrogen adsorption Gibbs free energy decreases to 0.004 eV under a bending curvature of 0.15 Å-1. The notable reversal in the catalytic capability of curved TMD monolayers can be primarily ascribed to the interplay between elastic energy stimuli and hydrogen adsorption energy barrier, alongside charge transfer to metal atoms facilitated by the weakening of M-X bonds and the exposure of metal atoms. A theoretical model has been established to elucidate the relationship among hydrogen adsorption Gibbs free energy, bending elastic energy, and adsorption energy barrier.

The impact of ligand chain length on the HER performance of atomically precise Pt6(SR)12 nanoclusters.

Atomically precise metal cluster-based electrocatalysts have been paid significant attention for an efficient hydrogen evolution reaction (HER). Herein, we have synthesized atomically precise Pt6(SR)12 nanoclusters using 3-mercaptopropionic acid (MPA), 6-mercaptohexanoic acid (MHA), 8-mercaptooctanoic acid (MOA), and 11-mercaptoundecanoic acid (MUA) thiol ligands in aqueous media at room temperature to understand the impact of ligand chain length on the HER performance. The composition of Pt6(SR)12 metal clusters was confirmed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Electrochemical studies confirmed that the HER performance of Pt6(SR)12 NCs is notably affected by the ligand chain length, and Pt6(MPA)12 exhibits an overpotential of 19 mV at a current density of 10 mA cm-2, which is several-fold higher than the Pt NCs developed in the recent past. The interfacial charge transfer kinetics and the HER performance decrease with the increase in the chain length of the thiol ligands. Density functional theory calculations showed that the Gibbs free energy for hydrogen adsorption decreases with decreasing chain length of the thiol ligand. The ligands used to synthesize Precise metal clusters for electrocatalysis play an essential role in their efficiency.

Hydrogen Evolution Reaction in Borophene: Puckering Mechanism and the Role of Coordination Number.

Using the free energy of hydrogen adsorption (ΔG H ) as the indicator, five borophene phases are previously shown to possess high catalytic activity for the hydrogen evolution reaction (HER). On these borophene phases, we investigate the role of the coordination number (CN = 4, 5, 6) of the adsorption sites and the puckering of the adsorption site. CN is discovered to have a profound effect on the ΔG H distribution, charge, and puckering height (h) of adsorption sites. Employing bonding indicators, we investigated the puckering mechanism. An increase in h directly increases the bond order and bond strength of the adsorption bond, but the associated energy cost of bond stretching hinders further puckering. The occupation and localization of σ orbitals determine the strength of local σ bonds-the key factors determining h. External biaxial strain is revealed to monotonically modulate the 2s character in local σ bonds, thus affecting bond stretchability, altering h and ΔG H subsequently. These insights are valuable for borophene-based HER applications and provide an analytical framework for the adsorption on 2D materials.

Electrophoretic Deposition of High Entropy Metal Phosphate Nanoparticles for Efficient Oxygen Evolution Reaction in Alkaline Media

Through electrolysis utilizing renewable energy sources such as solar and wind power, green hydrogen can be produced without unwanted byproducts. For efficient electrolysis, a high-performance oxygen evolution reaction (OER) catalyst is required. Transition metal-based catalysts in alkaline electrolysis have been extensively studied, offering not only their lower cost compared to noble metal catalysts including Pt, Ir, and Ru but also promising high stability and performance. Particularly, high entropy materials (HEMs) composed of five or more elements in a homogeneous mixture exhibit unique catalytic activity not solely explained by hydrogen adsorption energy, owing to the broadening and mixing of d-band centers of constituent elements. Furthermore, the overall stability of high-entropy materials (HEM) in catalytic reactions is attributed to solid-solution strengthening and the sluggish atomic diffusion effects resulting from their high entropy.In this work, we fabricated high entropy nanoparticles, where multiple elements are uniformly mixed, via a reverse precipitation method. The precursor introduced into the precipitant promptly reacted, disregarding the distinct precipitation rates of individual elements, successfully forming a random and homogeneous single phase, including transition metals (M = Cr, Mn, Co, Fe, Ni, Cu, and Zn). To further enhance catalytic performance, additional different sized atoms such as Mo and W were also incorporated during the synthesis process leading to lattice distortion of the surface atomic structure.To fabricate alkaline OER electrodes using synthesized catalysts, the Electrophoretic Deposition (EPD) method was utilized attaching nanoparticles onto substrates. The resulting catalyst electrodes exhibited optimized performance with two rounds of EPD process, each lasting 10 minutes at an applied voltage of 1000V on Ni foam. The electrode fabricated through EPD outperformed those made using drop casting with Nafion binder in experimental comparisons, demonstrating superior performance.

(Invited) Engineering Active Sites of 2D Materials for Active Hydrogen Evolution Reaction

Hydrogen evolution reaction (HER) is a promising solution for sustainable and clean energy source with zero carbon emission. Numerous studies have been conducted with versatile low dimensional materials, and the development of highly active electrochemical catalysts for HER has been one of the most important applications of the materials in the studies. Despite such extensive research, the physical origin of active catalytic performances from low dimensional materials remains unclear, which is distinguished from classical transition metal-based catalysts. Here, we review recent studies on intrinsic catalytic activity of two-dimensional (2D) semimetals, particularly among transition metal dichalcogenides (TMDs), highlighting promising strategies for the design of materials to further enhance their catalytic performances. An attractive approach for active HER is fabricating single-atom catalysts in the framework of TMDs. While electrochemical reaction at a catalytic atom for hydrogen evolution has been discussed by the Sabatier principle, we describe the phenomenon by Gibbs free energy for hydrogen adsorption via down-sizing, alloying, hybridizing, hetero-structuring, and phase boundary engineering mostly with TMDs. Thus, unique advantage of TMDs and their derivatives for HER are summarized, proposing research directions for promising design of low dimensional electrochemical catalysts for efficient HER and their energy applications.

Universal Platform for Robust Dual-Atom Doped 2D Catalysts with Superior Hydrogen Evolution in Wide pH Media

Layered 2D transition metal dichalcogenides (TMDs) have been suggested as efficient substitutes for Pt-group metal electrocatalysts in the hydrogen evolution reaction (HER). However, poor catalytic activities in neutral and alkaline electrolytes considerably hinder their practical applications. Furthermore, the weak adhesion between TMDs and electrodes often impedes long-term durability and thus requires a binder. Here, I present a universal platform for robust dual-atom doped 2D electrocatalysts with superior HER performance over a wide pH range media. V:Co-ReS2 on a wafer scale is directly grown on oxidized Ti foil by a liquid-phase precursor-assisted approach and subsequently used as highly efficient electrocatalysts. The catalytic performance surpasses that of Pt group metals in a high current regime (≥ 100 mA cm−2) at pH ≥ 7, with a high durability of more than 70 h in all media at 200 mA cm−2. First-principles calculations reveal that V:Co dual doping in ReS2 significantly reduces the water dissociation barrier and simultaneously enables the material to achieve the thermoneutral Gibbs free energy for hydrogen adsorption.

A Strongly Coupled 1T'-ReSe2@2H-MoSe2 van der Waals Heterostructure for Efficient Electrocatalytic Hydrogen Evolution at High Current Densities.

Developing efficient and durable non-noble metal electrocatalysts for high current-density hydrogen evolution reactions (HER) is a pressing requirement for commercial industrial electrolyzers. In this study, a vertical 1T'-ReSe2@2H-MoSe2 van der Waals heterostructure was developed through interface engineering to enhance the advantages of each component and expose numerous active sites. Experimental investigations and density functional theory calculations demonstrate significant electronic coupling at the interface between 1T'-ReSe2 and 2H-MoSe2, with suitable Gibbs free energy for hydrogen adsorption. The 1T'-ReSe2@2H-MoSe2 heterostructure catalyst achieves high current density HER with low overpotentials of 191 mV to generate up to 800 mA/cm2 in 0.5 M H2SO4, outperforming commercial 5 % Pt/C catalysts. Moreover, this catalyst exhibits rapid reaction kinetics and long-term durability, illustrating a successful approach to designing efficient heterostructure electrocatalysts for hydrogen production through interface engineering.

Exploration of Hydrogen Storage Exhibited by Rh‐Decorated Pristine and Defective Graphenes: A First‐Principles Study

ABSTRACTWe utilized density functional theory (DFT) to ascertain the storage of hydrogen in Rh‐decorated pristine (PG) and defective graphenes, primarily graphitic‐N (GNG) and pyridinic‐N (PNG). The binding energy of a single Rh atom on PG, GNG, and PNG was found to be −1.87, −2.18, and −4.01 eV, respectively. PG exhibits a weak adsorption energy of hydrogen molecules (−0.06 eV/H2). On the other hand, Rh‐decorated pristine and defective graphenes show incredibly higher hydrogen adsorption energy. As per the latest guidelines of the U.S. Department of Energy (DOE), the Rh‐decorated GNG (Rh@GNG) is found to be the best hydrogen storage material out of the three systems investigated here. The single Rh atom‐decorated GNG adsorbs up to 4H2. Uniform decoration of graphene surfaces with Rh atoms is necessary to improve hydrogen storage performance. Both sides of GNG surfaces are decorated with 8Rh atoms, which can adsorb up to 24H2 molecules, with an average adsorption energy of −0.33 eV/H2. The mechanism of H2 adsorption on the host system has been explored based on DFT‐evaluated deformation of charge density, partial density of states (PDOS), and non‐covalent interaction (NCI) plots. For a better understanding of the adsorption process, the diffusion energy barrier of Rh metal is computed using the climbing image nudged elastic band (CI‐NEB) method, and the thermal stability has been evaluated through ab initio molecular dynamics (AIMD) simulations.

Mo Migration‐Induced Crystalline to Amorphous Conversion and Formation of RuMo/NiMoO4 Heterogeneous Nanoarray for Hydrazine‐Assisted Water Splitting at Large Current Density

AbstractManipulating the atomic structure of the catalyst and tailoring the dissociative water‐hydrogen bonding network at the catalyst‐electrolyte interface is essential for propelling alkaline hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR), but remains a great challenge. Herein, we constructed an advanced a‐RuMo/NiMoO4/NF heterogeneous electrocatalyst with amorphous RuMo alloy nanoclusters anchored to amorphous NiMoO4 skeletons on Ni foam by a heteroatom implantation strategy. Theoretical calculations and in situ Raman tests show that the amorphous and alloying structure of a‐RuMo/NiMoO4/NF not only induces the directional evolution of interfacial H2O, but also lowers the d‐band center (from −0.43 to −2.22 eV) of a‐RuMo/NiMoO4/NF, the Gibbs free energy of hydrogen adsorption (ΔGH*, from −1.29 to −0.06 eV), and the energy barrier of HzOR (ΔGN2(g)=1.50 eV to ΔGN2*=0.47 eV). Profiting from these favorable factors, the a‐RuMo/NiMoO4/NF exhibits excellent electrocatalytic performances, especially at large current densities, with an overpotential of 13 and 129 mV to reach 10 and 1000 mA cm−2 for HER. While for HzOR, it needs only −91 and 276 mV to deliver 10 and 500 mA cm−2, respectively. Further, the constructed a‐RuMo/NiMoO4/NF||a‐RuMo/NiMoO4/NF electrolyzer demands only 7 and 420 mV to afford 10 and 500 mA cm−2.

Mo Migration-Induced Crystalline to Amorphous Conversion and Formation of RuMo/NiMoO4 Heterogeneous Nanoarray for Hydrazine-Assisted Water Splitting at Large Current Density.

Manipulating the atomic structure of the catalyst and tailoring the dissociative water-hydrogen bonding network at the catalyst-electrolyte interface is essential for propelling alkaline hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR), but remains a great challenge. Herein, we constructed an advanced a-RuMo/NiMoO4/NF heterogeneous electrocatalyst with amorphous RuMo alloy nanoclusters anchored to amorphous NiMoO4 skeletons on Ni foam by a heteroatom implantation strategy. Theoretical calculations and in situ Raman tests show that the amorphous and alloying structure of a-RuMo/NiMoO4/NF not only induces the directional evolution of interfacial H2O, but also lowers the d-band center (from -0.43 to -2.22 eV) of a-RuMo/NiMoO4/NF, the Gibbs free energy of hydrogen adsorption (ΔGH*, from -1.29 to -0.06 eV), and the energy barrier of HzOR (ΔGN2(g)=1.50 eV to ΔGN2*=0.47 eV). Profiting from these favorable factors, the a-RuMo/NiMoO4/NF exhibits excellent electrocatalytic performances, especially at large current densities, with an overpotential of 13 and 129 mV to reach 10 and 1000 mA cm-2 for HER. While for HzOR, it needs only -91 and 276 mV to deliver 10 and 500 mA cm-2, respectively. Further, the constructed a-RuMo/NiMoO4/NF||a-RuMo/NiMoO4/NF electrolyzer demands only 7 and 420 mV to afford 10 and 500 mA cm-2.

Regulating oxygen vacancies to optimize the electronic structure and catalytic activity of tungsten oxides for hydrogen evolution reaction

The undesirable intrinsic activity of tungsten oxides derived from poor conductivity and adverse hydrogen absorption energy is insufficient for their practical application. Herein, the tungsten oxides with adjustable oxygen vacancies were synthesized by a facile pyrolysis of ammonium paratungstate hydrate in controllable atmospheres. The structural characterizations confirmed that oxygen vacancies and crystalline phases in tungsten oxides depend on the pyrolysis atmosphere. The electrochemical test indicated a strong dependence between catalytic activity and oxygen vacancies in tungsten oxides. Combining experimental results and density functional theory calculations verified that introducing oxygen vacancies into tungsten oxides effectively modulates the surface electronic structure. The enhanced electronic conductivity by reducing band gap accelerates the electron transfer from catalysts into the reactive species. The optimized hydrogen adsorption energy by electron migration from O into W promotes the activation of reactive species at W sites and the desorption from O sites, thereby accelerating the reaction kinetics.

Designing Mo-based transition metal dichalcogenides for sustainable hydrogen production: Anionic substitution and DFT insight

Anionic substitution is an effective approach to optimize the catalytic activity of Mo based transition metal dichalcogenide (TMD)- MoS2 towards hydrogen evolution reaction (HER). By optimizing the S-to-Se ratio, materials with the ideal Gibbs free energy of hydrogen adsorption (ΔGH) values are synthesized (MoS2, MoS1.4Se0.6, MoS1.2Se0.8, MoSSe, MoSe2) and their HER performance is examined in 0.5 M H2SO4 solution. Density functional theory calculations of hydrogen adsorption energy on the surface of the electrocatalysts show that Se substitution facilitates electron transfer between the catalyst surface and the hydrogen donor, thereby lowering the additional potential required for water splitting, making MoS1.2Se0.8 the most favorable HER electrocatalyst with the lowest value of adsorption energy. Further enhancement in the electrocatalytic activity of mixed anion TMDs has been achieved by the incorporation of carbon nanotubes (CNTs). MoS1.2Se 0.8-CNT nanocomposite exhibits superior HER performance with an overpotential of 118 mV and a Tafel slope of 63 mV/decade as compared to MoS1.2Se0.8 sample owing to the synergetic effect from CNTs and MoS1.2Se0.8.

Machine learning prediction of hydrogen adsorption energy on platinum nanoclusters: A comparative study of SOAP descriptors

Hydrogen binding energy in metal materials is of high significance in the hydrogen storage as well as the hydrogen evolution reaction of electrocatalysis. In this work, the datasets (more than 9000 data) of hydrogen adsorbed on Pt nanoclusters with different sizes are obtained by first-principles calculations. Data analysis shows that the binding strength of hydrogen with Pt is closely relevant to the local structures of the adsorption sites. The local features of the distance between the platinum and hydrogen and the size of the nanoclusters are supplemented to the Smooth Overlap of Atomic Positions descriptors to fit and predict the adsorption energies of hydrogen on different Pt nano-structures by performing the machine learning method. Gaussian Process Regression (GPR) and Random Forest Regressor (RFR) are used to construct the prediction model of hydrogen binding energies and it is found the R2 of test set is improved from 0.63 to 0.78 with modified descriptors. By applying it into other nanoclusters, the MAE of the prediction model is 0.08 eV, which exhibits high accuracy of the hydrogen adsorption energy. Our model can be easily extended to the prediction of hydrogen adsorption energy of other materials with affordable computational cost and accuracy, which would be helpful for the structural design of high-performance catalysts.

Ti-decorated B-doped biphenylene: A hydrogen storage sponge at room temperature

It has always been a difficult problem to design Kubas-type hydrogen storage materials that make hydrogen molecules activate but do not dissociate. Density functional theory calculations confirm that Ti decorated B-doped biphenylene is the first two-dimensional room-temperature hydrogen storage sponge reported so far. The hydrogen adsorption energy of Ti-decorated B-doped biphenylene is in the range of −0.29 ∼ −0.51 eV with hydrogen storage capacity is 6.58–9.13 wt%. What's very interesting and exciting is that the Kubas interaction between Ti sites and H2 can be regulated by changing the electron occupation state of the dx2-y2 orbitals of Ti, and this regulation can be realized through the uniaxial lattice strain in the XOY plane. The average hydrogen adsorption energy of tensile Ti-decorated B-doped biphenylene ranges between −0.34 ∼ −0.66 eV, while −0.22 ∼ −0.48 eV for compressed one. This process makes the reversible hydrogen storage as simple and feasible as a sponge absorbing water. This study provides clear structural for the transformation mechanism to form a folded structure and also provides an important precedent model.

Integrating Pt single atoms and Mo into PtNi/C through Mo doping-displacement synchronisation strategy for enhanced HER at all pH values

This paper proposes a Mo doping-displacement synchronization strategy to integrate Pt SAs and Mo atoms into PtNi/C, synthesizing Pt SAs/Mo-doped PtNi octahedra/carbon support catalyst (Pt SAs/Mo-PtNi/C). In this approach, Mo atoms are doped into PtNi alloy octahedra and displace some Pt atoms, forming Mo-PtNi octahedra. Importantly, the substituted Pt atoms can adhere to carbon substrate, creating Pt SAs. Pt SAs/Mo-PtNi/C exhibits lower overpotentials (38, 59, and 110 mV at 10 mA cm−2) and smaller Tafel slopes (44, 51, and 139 mV dec-1) in acidic, alkaline, and neutral environments. Additionally, the electron pathway of Mo-PtNi → Pt SAs/C has been confirmed, and Pt SAs/Mo-PtNi/C exhibits an optimized hydrogen adsorption energy (ΔGH*=-0.29 eV). Furthermore, catalyzed by Pt SAs/Mo-PtNi/C, the H-O bond length of H2O extends to 1.11 Å and the bond angle reduces to 102.741°, directly confirming that the Pt SAs and doped Mo could facilitate H-O bond breaking. The proposed Mo doping-displacement synchronization strategy not only simplifies the fabrication process of Pt SAs catalyst, but also improves its durability and activity across a wide pH range, thereby potentially advancing hydrogen production technologies.