The hydrogen overpotential—hydrogen adsorption energy relationship. A new approach to the problem

2016 ◽  
Vol 218 ◽  
pp. 125-132 ◽  
Author(s):  
Lev I. Krishtalik
Keyword(s):  
Adsorption Energy ◽  
Hydrogen Adsorption ◽  
New Approach ◽  
Hydrogen Overpotential

Flower-like tungsten-doped Fe–Co phosphides as efficient electrocatalysts for hydrogen evolution reaction

CrystEngComm ◽  
2021 ◽  
Author(s):  
Qian Zhang ◽  
Shuihua Tang ◽  
Lieha Shen ◽  
Weixiang Yang ◽  
Zhen Tang ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Adsorption Energy ◽  
High Performance ◽  
Hydrogen Adsorption ◽  
Cost Effective

Developing cost-effective and high-performance electrocatalysts for hydrogen evolution reaction (HER) are imperative thanks to rapid increase of fuel-cell driven vehicles. Tungsten (W) possesses advantages of optimized hydrogen adsorption energy and...

scholarly journals Insights into Hydrogen Evolution Reaction on 2D Transition Metal Dichalcogenides

2021 ◽  
Author(s):  
Zhenbin Wang ◽  
Michael Tang ◽  
Ang Cao ◽  
Karen Chan ◽  
Jens Kehlet Nørskov
Keyword(s):  
Transition Metal ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Adsorption Energy ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Activation Barrier ◽  
Transition Metal Dichalcogenides ◽  
Adsorbed Hydrogen ◽  
Metal Dichalcogenides

<p>Understanding the hydrogen evolution reaction (HER) behaviors over 2D transition metal dichalcogenides (2D-TMDs) is critical for the development of non-precious HER electrocatalysts with better activity. In this work, by combining density functional theory calculations with microkinetic modelling, we thoroughly investigated the HER mechanism on 2D-TMDs. We find there is an important dependence of simulated cell size on the calculated hydrogen adsorption energy and the activation barrier for MoS<sub>2</sub>. Distinct from previous “H migration” mechanisms proposed for the Heyrovsky reaction − the rate-determining step for MoS<sub>2</sub>, we propose the Mo site only serves as the stabilized transition state rather than H adsorption. In comparison to transition metal electrocatalysts, we find that the activation barrier of the Heyrovsky reaction on 2D-TMDs scales with the hydrogen adsorption energy exactly as for transition metals except that all activation energies are displaced upwards by <i>ca.</i> 0.4 eV. This higher Heyrovsky activation barrier is responsible for the substantially lower activity of 2D-TMDs. We further show that this higher activation barrier stems from the more positively charged adsorbed hydrogen on the chalcogenides interacting repulsively with the incoming proton. Based on these insights, we discuss potential strategies for the design of non-precious HER catalysts with activity comparable to Pt.</p>

Designing and Encapsulation of Inorganic Al12N12 Nanoclusters with Be, Mg, and Ca Metals for Efficient Hydrogen Adsorption: A Step Forward Towards Hydrogen Storage Materials

2021 ◽  
pp. 1-19
Author(s):  
Muhammad Yasir Mehboob ◽  
Riaz Hussain ◽  
Zobia Irshad ◽  
Ume Farwa ◽  
Muhammad Adnan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Hydrogen Storage ◽  
Adsorption Energy ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
Energy Gap ◽  
Earth Metal ◽  
Partial Density ◽  
Geometrical Parameters ◽  
Adsorption Parameters

Nanoclusters such as Al[Formula: see text]N[Formula: see text] have received increased attention due to their diverse applications in the fields of optoelectronics and energy storage. In this paper, we have investigated a series of alkaline earth metal (AEM)-encapsulated Al[Formula: see text]N[Formula: see text] nanoclusters for hydrogen adsorption. Thermodynamic adsorption parameters, optical and nonlinear optical properties were investigated using density functional theory (DFT) at the B3LYP/6-31G(d,p) level of theory. Encapsulation of AEMs (Be, Mg and Ca) is an effective strategy to improve the NLO reaction and thermodynamic and adsorption properties of Al[Formula: see text]N[Formula: see text] nanoclusters. The adsorption energies ranging from [Formula: see text]26.57[Formula: see text]kJ/mol to [Formula: see text]213.33[Formula: see text]kJ/mol for the three guests (Be, Mg and Ca) capsulated Al[Formula: see text]N[Formula: see text] nanoclusters are observed. The adsorption energy is affected by the size of the nanocage. Therefore, Ca- and Mg-encapsulated cages show higher values of adsorption energy. Overall, an increase in adsorption energy ([Formula: see text][Formula: see text]kJ/mol to [Formula: see text]91.06[Formula: see text]kJ/mol) is observed for (Be, Mg and Ca) encapsulated Al[Formula: see text]N[Formula: see text] nanoclusters compared to untreated Al[Formula: see text]N[Formula: see text] and H2-Al[Formula: see text]N[Formula: see text] cages. Moreover, adsorption of hydrogen on AEMs encapsulated in Al[Formula: see text]N[Formula: see text] leads to a decrease in the HOMO-LUMO energy gap with an enhancement of linear and nonlinear hyperpolarizability. All hydrogen-adsorbed AEMs Al[Formula: see text]N[Formula: see text] nanocages exhibit large [Formula: see text] and [Formula: see text] values, suggesting that these systems are potential candidates for optical materials. Various geometrical parameters such as frontier molecular orbitals (FMOs), partial density of states, global quantum descriptor of reactivity, natural bond orbital testing and molecular electrostatic strength analyses were performed to investigate the thermodynamic stability of all the studied systems. The results obtained confirmed that the designed systems are suitable for hydrogen storage. Therefore, we recommend that these systems be investigated for their hydrogen storage and optical properties.

SIMULATION OF HYDROGEN ADSORPTION IN MOLECULAR SIEVES

2013 ◽  
Vol 27 (20) ◽  
pp. 1350143 ◽  
Author(s):  
WEI DAI ◽  
JIA-JING XU
Keyword(s):  
Monte Carlo ◽  
Pore Structure ◽  
Adsorption Energy ◽  
Molecular Sieves ◽  
Hydrogen Adsorption ◽  
Capillary Condensation ◽  
Analysis Method ◽  
Grand Canonical Monte Carlo ◽  
Grand Canonical ◽  
Micropore Analysis

The grand canonical Monte Carlo (GCMC) technique is used to investigate the adsorption capacity of hydrogen in AlPO 4 and AFT molecular sieves. Results show that the hydrogen storage capacities of AlPO 4 and AFT are 513 m3/g and 475 m3/g respectively at 77 K and 10 MPa. By applying Dubinin–Astakhov (DA) micropore analysis method, it is found that the apertures of AlPO 4-18 zeolite mainly distribute in the range of 8–25 Å, and the apertures of AFT zeolite mainly distribute in the range of 10–28 Å. AlPO 4-18 zeolite contains more micropores, which enhance the adsorption energy and enable the hydrogen to arise capillary condensation. It proves that, the microlization of the pore structure will facilitate the adsorption of hydrogen.

scholarly journals Factors Affecting Hydrogen Adsorption in Metal–Organic Frameworks: A Short Review

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1638
Author(s):  
Vladimír Zeleňák ◽  
Ivan Saldan
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Adsorption ◽  
Metal Organic Frameworks ◽  
Hydrogen Uptake ◽  
Short Review ◽  
High Rate ◽  
New Approach ◽  
Factors Affecting ◽  
Metal Organic ◽  
Near Future

Metal–organic frameworks (MOFs) have significant potential for hydrogen storage. The main benefit of MOFs is their reversible and high-rate hydrogen adsorption process, whereas their biggest disadvantage is related to their operation at very low temperatures. In this study, we describe selected examples of MOF structures studied for hydrogen adsorption and different factors affecting hydrogen adsorption in MOFs. Approaches to improving hydrogen uptake are reviewed, including surface area and pore volume, in addition to the value of isosteric enthalpy of hydrogen adsorption. Nanoconfinement of metal hydrides inside MOFs is proposed as a new approach to hydrogen storage. Conclusions regarding MOFs with incorporated metal nanoparticles, which may be used as nanoscaffolds and/or H2 sorbents, are summarized as prospects for the near future.

scholarly journals Competitive Adsorption of H2O and SO2 on Catalytic Platinum Surfaces: a Density Functional Theory Study

2021 ◽  
Vol 74 ◽  
Author(s):  
Marietjie J. Ungerer ◽  
David Santos-Carballal ◽  
Cornelia G.C.E. van Sittert ◽  
Nora H. de Leeuw
Keyword(s):  
Density Functional Theory ◽  
Adsorption Energy ◽  
Sulphur Dioxide ◽  
Density Functional ◽  
Competitive Adsorption ◽  
Hydrogen Adsorption ◽  
Surface Reactivity ◽  
Functional Theory ◽  
Sulphur Poisoning ◽  
Production Of Hydrogen

ABSTRACT Platinum has been widely used as the catalyst of choice for the production of hydrogen in the hybrid sulphur (HyS) cycle. In this cycle, water (H2O) and sulphur dioxide (SO2) react to form sulphuric acid and hydrogen. However, the surface reactivity of platinum towards H2O and SO2 is not yet fully understood, especially considering the competitive adsorption that may occur on the surface. In this study, we have carried out density functional theory calculations with long-range dispersion corrections [DFT-D3-(BJ)] to investigate the competitive effect of both H2O and SO2 on the Pt (001), (011) and (111) surfaces. Comparing the adsorption of a single H2O molecule on the various Pt surfaces, it was found that the lowest adsorption energy (Eads = -1.758 eV) was obtained for the dissociative adsorption of H2O on the (001) surface, followed by the molecular adsorption on the (011) surface (Eads = -0.699 eV) and (111) surface (Eads = -0.464 eV). For the molecular SO2 adsorption, the trend was similar, with the lowest adsorption energy (Eads = -2.471 eV) obtained on the (001) surface, followed by the (011) surface (Eads = -2.390 eV) and (111) surface (Eads = -1.852 eV). During competitive adsorption by H2O and SO2, the SO2 molecule will therefore preferentially adsorb onto the Pt surface. If the concentration of SO2 increases, self-reaction between two neighbouring SO2 molecules may occur, leading to the formation of sulphur monoxide (SO) and -trioxide (SO3) on the surface, which could lead to sulphur poisoning of the Pt catalytic surface. Keywords: Platinum, water, sulphur dioxide, hydrogen, adsorption, density functional theory.

scholarly journals Tuning the electrocatalytic activity of Pt by structurally ordered PdFe/C for the hydrogen oxidation reaction in alkaline media

2018 ◽  
Vol 6 (24) ◽  
pp. 11346-11352 ◽  
Author(s):  
Weiping Xiao ◽  
Wen Lei ◽  
Jie Wang ◽  
Guoying Gao ◽  
Tonghui Zhao ◽  
...  
Keyword(s):  
Adsorption Energy ◽  
Electrocatalytic Activity ◽  
Oxidation Reaction ◽  
Hydrogen Adsorption ◽  
Hydrogen Oxidation ◽  
Alkaline Media ◽  
Hydrogen Oxidation Reaction

Tuning the hydrogen adsorption energy on Pt surface is essential for enhancing the HOR performance in alkaline media.

Enhancements of hydrogen adsorption energy in M-MOF-525 (M= Ti, V, Zr and Hf): A DFT study

2020 ◽  
Vol 64 ◽  
pp. 326-332 ◽  
Author(s):  
P. Suksaengrat ◽  
V. Amornkitbamrung ◽  
P. Srepusharawoot
Keyword(s):  
Adsorption Energy ◽  
Hydrogen Adsorption ◽  
Dft Study

scholarly journals Volcano plots in hydrogen electrocatalysis – uses and abuses

2014 ◽  
Vol 5 ◽  
pp. 846-854 ◽  
Author(s):  
Paola Quaino ◽  
Fernanda Juarez ◽  
Elizabeth Santos ◽  
Wolfgang Schmickler
Keyword(s):  
Hydrogen Evolution ◽  
Rate Constant ◽  
Adsorption Energy ◽  
Reaction Rate ◽  
Hydrogen Adsorption ◽  
Good Catalyst ◽  
Volcano Plots ◽  
Intermediate States ◽  
Constant Versus

Sabatier’s principle suggests, that for hydrogen evolution a plot of the rate constant versus the hydrogen adsorption energy should result in a volcano, and several such plots have been presented in the literature. A thorough examination of the data shows, that there is no volcano once the oxide-covered metals are left out. We examine the factors that govern the reaction rate in the light of our own theory and conclude, that Sabatier’s principle is only one of several factors that determine the rate. With the exception of nickel and cobalt, the reaction rate does not decrease for highly exothermic hydrogen adsorption as predicted, because the reaction passes through more suitable intermediate states. The case of nickel is given special attention; since it is a 3d metal, its orbitals are compact and the overlap with hydrogen is too low to make it a good catalyst.

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