共查询到11条相似文献,搜索用时 0 毫秒
1.
《International Journal of Hydrogen Energy》2019,44(50):27421-27428
Electrochemical water splitting to hydrogen is considered as a promising approach for clean H2 production. However, developing highly active and inexpensive electrocatalysts is an important part of the hydrogen evolution reaction (HER). Herein, we present a multifaceted atom (sp2-and sp-hybridized boron) doping strategy to directly fine-modify the electronic structures of the active site and the HER performance by the density functional theory calculations. It is found that the binding strength between the Co atom and the B doped graphyne nanosheets can be enhanced by doping B atoms. Meanwhile, the Co@B1-GY and Co@B2-GY catalysts exhibit good thermodynamic stability and high HER catalytic activity. Interestingly, the Co@B2-GY catalyst has an ideal HER performance with the ΔGH* value of −0.004 eV. Moreover, the d-band center of the Co atoms is upshifted by the sp2-or sp-hybridized B dopants. The concentrations of the sp-hybridized B atoms have a positive effect on the electrons transformation of the Co atoms. The interaction between the H and Co atoms becomes strong with the increase of the concentrations of the sp-hybridized B atoms and thus the corresponding catalysts show sluggish HER kinetics. This investigation could provide useful guidance for the experimental groups to directly and continuously control the catalytic activity towards HER by precisely doping multifaceted atoms. 相似文献
2.
《International Journal of Hydrogen Energy》2023,48(48):18326-18337
Here, we report a theoretical design of transition metals (TMs) anchored two-dimensional (2D) holey graphyne (HGY) based catalyst for the hydrogen evolution reaction (HER) through state-of-art density functional theory (DFT) simulation. The studied TMs (Co, Fe, Cr) are bonded strongly on HGY surface due to charge transfer from d orbital of metal to C 2p orbital of HGY. The HGY+TMs systems are stable at room temperature as evident from ab-initio molecular dynamics (AIMD) simulation. We predicted that the Co, Fe and Cr anchored HGY are highly active for HER activity with Gibbs free energy (ΔG) value as low as −0.21, −0.14, and −0.05 eV respectively and which are close to the best-known HER catalyst (Pt metal). The enhanced HER performance is attributed to the increased conductivity as well as redistribution of electrons. As pristine HGY is experimentally synthesized, HGY+TMs (Co, Fe, Cr) systems can be as an efficient catalyst for H2 production. 相似文献
3.
《International Journal of Hydrogen Energy》2023,48(13):5138-5151
In this work, a detailed investigation of the structural and electronic properties and hydrogen evolution reaction (HER) activity of the pristine, vacancy and carbon (C) doped o-B2N2 monolayer is carried out using first-principles based density functional theory. The creation of vacancy and C doping modulates structural and electronic properties of the monolayers and enhances the HER activity of o-B2N2. The BN vacancy defect, C doping at B and N sites in the monolayer enhances the magnitude of HER activity by 77.34%, 86.71% and 83.59% as compared to pristine monolayer. The modulation in the HER activity of the o-B2N2 is due to the redistribution of charge after induction of vacancy and dopant. Our results suggest that the C doping makes o-B2N2 metallic which can be utilized as an “electrocatalyst” whereas BN vacancy defected o-B2N2 monolayer is semiconducting with a band gap of ~1 eV and can be used as “photocatalyst” for HER activity. 相似文献
4.
《International Journal of Hydrogen Energy》2023,48(21):7621-7631
Electrocatalytic nitrogen reduction reaction (NRR) provides a green and sustainable way to produce ammonia at ambient conditions. The key to realize highly efficient NRR is the catalysts. To design highly active electrocatalysts for NRR, the multistep mechanism involved in NRR must be clearly unraveled. Herein, single V atoms anchored on g-C3N4 is identified to be an efficient electrocatalyst for NRR by screening single 3d transition metal (TM = Sc to Zn) atoms anchored by g-C3N4 (TM@g-C3N4) through density functional theory calculations. NRR takes place on V@g-C3N4 preferentially through distal path with a relatively low limiting potential of ?0.55 V. The outstanding NRR performance of V@g-C3N4 is found from the peculiar electronic structure of V after anchored in the six-fold cavity of g-C3N4 and the good transmitter role of V for electron transfer between NxHy species and g-C3N4. Moreover, the formation energy and dissolution potential indicate that V@g-C3N4 is thermodynamically and electrochemically stable and the aggregation of V atoms is unfavorable thermodynamically, signifying that the synthesis of V@g-C3N4 is feasible in experiments. Our work screens out a superior noble metal-free NRR electrocatalyst and will be helpful for the development of ambient artificial nitrogen fixation. 相似文献
5.
《International Journal of Hydrogen Energy》2022,47(8):5292-5306
Conversion of N2 to NH3 through electrochemical technology is one of the most attractive and promising alternatives to the traditional Haber-Bosch method. However, exploring the promising electrocatalysts with high stability, activity and selectivity for nitrogen reduction reaction (NRR) is still an important and long-standing challenge to accelerate the green production of NH3. Herein, through the first-principles high-throughput screening, we systematically investigated the potentiality of single transition metal (TM) anchored on defective C3N monolayer as TM-VCC candidates for N2 fixation. We carried out a comprehensive screening and systematical evaluation for stability, catalytic activity and selectivity toward NRR on TM-VCC candidates. Our results reveal that, among 26 candidates, Mn-VCC can significantly suppress HER and exhibit the outstanding NRR activity, with the most favorable limiting potential of ?0.75 V through the distal pathway, which is better than the currently stepped catalyst Ru (0001). More impressively, such a satisfactory NH3 conversion is primarily ascribed to the strong back-donation interactions between d-electrons of Mn atom and the anti-orbitals of N2 molecule, as well as efficient charge transfer of electrochemical process. Our findings not only broaden the development prospect of SACs for N2 reduction but also pave a way for rational design and rapid screening of highly active C3N-based catalysts for NRR. 相似文献
6.
《International Journal of Hydrogen Energy》2023,48(8):2990-2997
The development of effective and non-precious electrocatalyts for hydrogen evolution reaction (HER) has attracted massive research interests. Herein, we report a density functional theory (DFT) investigation on the activation and optimization of Molybdenum disulfide (MoS2) monolayer as efficient HER electrocatalysts by cobalt-nonmetal atom (X = B, C, N, P, Se) codoping. Our results show that three CoX-MoS2 (X = C, N, and Se) catalysts display enhanced HER performance with |ΔGH|s in the range of 0.12–0.23 eV. Careful electronic structure analysis manifests that the favorable H adsorption process on the MoS2 basal plane is induced by suitable in-gap states upon codoping. Furthermore, appropriate biaxial strain can help optimize the HER performance of these co-doped systems, e.g, the ΔGHs of CoC@MoS2, CoN@MoS2, and CoSe@MoS2 reaches 0.0 eV, ?0.04 eV, and ?0.01 eV at 1.86% tensile strain, 5% compressive strain, and 4% compressive strain, respectively. Our work offers a highly promising catalyst for HER and guides the atomic design of more efficient non-noble electrocatalysts. 相似文献
7.
8.
Shulin Yang Yanan Liu Gui Lei Yulin Xie Liping Peng Huoxi Xu Zhao Wang Haoshuang Gu 《International Journal of Hydrogen Energy》2021,46(47):24233-24246
The adsorption of hydrogen (H2) molecules on MoS2 monolayers doped with Fe, Co, Ni, Ru, Rh, Pd, Os, Ir or Pt was calculated via first-principle density functional theory (DFT). The H2 was found to interact most strongly with the MoS2 doped with Os with a higher adsorption energy of ?1.103 eV. Investigations of the adsorptions of two to five H2 molecules on Os-doped MoS2 monolayers indicate that there are at most four H2 interacting stably with the substrate with a promising average adsorption energy of ?0.792 eV. Molecular dynamics simulations also confirmed that the four H2 molecules can still be reasonably adsorbed and stored on the Os-doped MoS2 monolayer with a comparable average adsorption energy of ?0.713 eV at 300 K. This study indicates that MoS2 monolayer doped with Os is a promising substrate to interact strongly with H2 and can be applied to effectively store H2 at room temperature. 相似文献
9.
Akari Narayama Sosa Francisco de Santiago Álvaro Miranda Alejandro Trejo Fernando Salazar Luis Antonio Pérez Miguel Cruz-Irisson 《International Journal of Hydrogen Energy》2021,46(38):20245-20256
In this work, we have performed density functional theory-based calculations to study the adsorption of H2 molecules on germanene decorated with alkali atoms (AM) and transition metal atoms (TM). The cohesive energy indicates that interaction between AM (TM) atoms and germanene is strong. The values of the adsorption energies of H2 molecules on the AM or TM atoms are in the range physisorption. The K-decorated germanene has the largest storage capacity, being able to bind up to six H2 molecules, whereas the Au and Na atoms adsorbed five and four H2 molecules, respectively. Li and Ag atoms can bind a maximum of three H2 molecules, while Cu-decorated germanene only adsorbed one H2 molecule. Formation energies show that all the studied cases of H2 molecules adsorbed on AM and TM atom-decorated germanene are energetically favorable. These results indicate that decorated germanene can serve as a hydrogen storage system. 相似文献
10.
《International Journal of Hydrogen Energy》2022,47(85):36149-36162
Could materials only including non-noble metals be good HER catalysts? To deal with this puzzle, computational screening of 132 different non-noble transition metal A/B surfaces for HER (A monolayer on B), are carried out by first-principles calculations systematically. The formation energies and dissolution potentials are calculated to access stabilities of A/B in vacuum and in solution, respectively. The realistic catalytic surfaces with oxygen or hydroxyl (co)adsorption are confirmed by analyzing Surface Pourbaix diagrams. Finally, three A/B surfaces (Cu/Mo, Mo/W, and Ti/Nb) with high stabilities and high HER exchange current densities (8.51, 3.39, 2.83 mA/cm2) are screened out. Further electronic properties analysis reveals that the different interactions between H 1s and d orbital, s orbital of A atoms will determine the feasible application of d and s band centers to uncover water effect and substrate effect on hydrogen adsorption ability, and tune the HER activity of A/B in the end. 相似文献