Effects of van der Waals Dispersion Interactions in Density Functional Studies of Adsorption, Catalysis, and Tribology on Metals

Yuan, Dingwang; Zhang, Yanning; Ho, W.; Wu, Ruqian

doi:10.1021/acs.jpcc.0c02293

Cited by 26 publications

(21 citation statements)

References 172 publications

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“…Yuan et al used density functional theory (DFT) to show that due to the Van der Waals (VdW) force provided by the adsorbates, noticeable charge redistribution happens on the surface of the catalyst, which may restrict the catalytic activity of the catalyst. [ 21 ] Matanovic and co‐workers suggested that when the aromatic polymer is used as the ionomer binder in AEMFCs, the interaction between metal catalyst and ionomer binder in the CL is mainly decided by the adsorption of benzene on the catalyst surface, which determines the adsorption energy and catalytic activity of the CL. [ 22 ] Meanwhile, the electrostatic repulsion between the ionomer binder and metal catalyst possibly affects their adsorption interaction, which decides the micromorphology of the CL.…”

Section: Introductionmentioning

confidence: 99%

Interaction Regulation Between Ionomer Binder and Catalyst: Active Triple‐Phase Boundary and High Performance Catalyst Layer for Anion Exchange Membrane Fuel Cells

et al. 2021

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As one of the most crucial components, the catalyst layer (CL) plays a critical role in the performance of anion exchange membrane fuel cells (AEMFCs). However, the effect of the structural evolution of ionomer binder on the micromorphology and catalytic activity of CL is yet to be clarified. In this study, pyrrolidinum and quaternary ammonium cations are attached to the polyphenylene oxide (PPO) backbone through flexible spacer units (five, seven, or nine carbon atoms) with different terminal alkyl groups. The Van der Waals force and electrostatic repulsion between the ionomer binder and catalyst are regulated through the flexible spacer units and terminal alkyl groups to alleviate the agglomeration of catalyst particles and acquire a high catalytic activity. To evaluate the electrochemical stability of the cationic groups, the alkaline stability of the ionomer binder is tested under a constant voltage to simulate the true operational environment of the fuel cells. The results reveal that the degradation of the cation groups of ionomer binder is accelerated under a constant voltage condition. This phenomenon in neglect earlier, may serve as a useful reference for the synthesis and performance enhancement of ionomer binders.

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Section: Introductionmentioning

confidence: 99%

Interaction Regulation Between Ionomer Binder and Catalyst: Active Triple‐Phase Boundary and High Performance Catalyst Layer for Anion Exchange Membrane Fuel Cells

et al. 2021

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“…The interlayer couplings of all TDNMs are considered as the combined actions of vdW force and Coulomb potential, [ 32 ] so the load‐driven lubricities should be extremely similar for all layered materials. In addition to h ‐BN/ h ‐BN, Gr/Gr, and MoS 2 /MoS 2 , we also investigate the critical pressures for other 2D systems to achieve superlubricity and present interlaminar shear forces under the zero and optimal loads in Figure .…”

Section: Resultsmentioning

confidence: 99%

Superlubricity Enabled by Load‐Driven Redistribution of Electrons

Cheng

Sun

Zhang

et al. 2022

Adv Materials Inter

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How to reduce friction is a key issue of tribology and plays an important role in solving a number of problems of physics and engineering, e.g., the durability of the nano-friction generator. [2] The well-known and widely used Amontons-Coulomb friction law stipulates that the tangential frictional force is proportional to the normal compressive force. [3] With the main advantage of being simple, this phenomenological macroscopic law fails to be applicable in the field of nano-tribology. [4] Indeed, nano-friction is affected by a number of factors such as the deformations of the components in contact and the degree of atomic mismatches at the contacting interfaces. [5,6] In recent years, a promising fundamental approach to quantitatively understanding micro-or nano-friction consists in determining the redistribution of electrons due to pressure and sliding. [7][8][9] This approach has been successfully used to reveal the relationship between adsorption and static friction and the one between in-plane strain and friction. [10,11] But, to the best of our knowledge, it has not yet been elaborated and applied to establish a direct and quantitative relationship between friction and electrons redistribution driven by the normal load.Some pioneering works have shown that quasi-zero friction or superlubricity is feasible. [12][13][14][15] At present, there are two main strategies for achieving frictionless sliding between both solids in contact: structural superlubricity (SSL) and pressuredriven superlubricity. [12][13][14] SSL occurs only if two contacting surfaces that slide one on the other are incommensurable. [16] It was theoretically predicted and shown to be achievable for microscopic phenomena and even for engineering design. [14,17] Nevertheless, it is very difficult to prepare and keep both ultra-clean surfaces in incommensurate contact. [18] Thus, it is urgent to seek an alternative solution to avoid the harsh incommensurate contact required for SSL. Fortunately, a few works have indicated that the external load may regulate friction to superlubricity even in a commensurate contact. [12,19,20] Initially, pressure-and tension-actuated frictionless sliding was expected to be realized at a gas-solid interface (rare gas layers and metal surfaces), [12,19] but the structural instability of rare gas layer limited further experimental explorations. Recently, the pressure-induced friction collapse rekindles hope for load-driven superlubricity at 2D solid-solid interfaces. [13,20] However, the exploration of load-driven superlubricity has fallen into another dilemma: the critical load of ≈300 GPa required for superlubricity is so demanding that it is experimentally unrealistic. [13] By first-principles calculations, it is shown that the friction at solid-solid interfaces between 2D nanomaterials (TDNMs), such as h-BN and graphene, can be reduced nearly to zero even if the normal load is smaller than 5 GPa. The quantitative analysis of interfacial charge density demonstrates a detailed process in which the pressure-dr...

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“…The 11 × 11 × 1 Γ-centered k-mesh was used for the structure optimizations and self-consistent electronic structure calculations. Compared with the DFT-D2 method, the DFT-D3 method can not only ensure better overall accuracy but also support more elements when describing the vdW dispersion. − The DFT-D3 method was used to accurately describe the vdW interactions in the Janus III–VI vdW heterostructures . To take into account the existence of asymmetric Janus structures, the dipole correction was employed for all the calculations.…”

Section: Methodsmentioning

confidence: 99%

High-Throughput Computational Screening and Machine Learning Modeling of Janus 2D III–VI van der Waals Heterostructures for Solar Energy Applications

Zheng

et al. 2022

Chem. Mater.

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Two-dimensional Janus III−VI monolayers and corresponding van der Waals (vdW) heterostructures present immense application potential in the solar energy conversion areas. In this work, we present material screening and machine learning modeling to accelerate the discovery of promising photocatalytic and photovoltaic candidates in Janus III−VI vdW heterostructures. A comprehensive database with a total of 19926 heterostructures has been proposed according to the high-throughput firstprinciples calculations. It is highlighted that we develop an accurate machine learning model using only atoms and bonds as descriptors based on the crystal graph convolutional neural network framework. Besides, 1035 Janus III−VI vdW heterostructures have been screened out according to the essential criteria of stability. Moreover, we find 66 and 71 potential candidates for photocatalysis and solar cells, respectively, from further application-driven screening. Interestingly, the screened type-II SeInAlS/ SeGaAlTe heterostructure with a band gap of 1.18 eV is highlighted as an internal electric field-driven asymmetrical photocatalyst. On the other hand, the type-II Al 2 STe/Al 2 SSe heterostructure solar cell presents power conversion efficiencies higher than 21% both from the microscopic and mesoscopic point of views. We believe that our study will provide a feasible strategy for the design of III− VI monolayers for solar energy applications.

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Effects of van der Waals Dispersion Interactions in Density Functional Studies of Adsorption, Catalysis, and Tribology on Metals

Cited by 26 publications

References 172 publications

Interaction Regulation Between Ionomer Binder and Catalyst: Active Triple‐Phase Boundary and High Performance Catalyst Layer for Anion Exchange Membrane Fuel Cells

Interaction Regulation Between Ionomer Binder and Catalyst: Active Triple‐Phase Boundary and High Performance Catalyst Layer for Anion Exchange Membrane Fuel Cells

Superlubricity Enabled by Load‐Driven Redistribution of Electrons

High-Throughput Computational Screening and Machine Learning Modeling of Janus 2D III–VI van der Waals Heterostructures for Solar Energy Applications

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