DFT exploration of sensor performances of two-dimensional WO3 to ten small gases in terms of work function and band gap changes and I-V responses
A combination of density functional theory (DFT) and nonequilibrium Green function (NEGF) based simulation was employed to investigate the prospects of two-dimensional (2D) WO3 materials for gas sensing applications. The target gas molecules considered are O2, N2, NH3, NO, CO, CO2, CH4, C2H6, HCHO, and H2S. Our computed binding energies suggested that the interactions between the gas molecules and 2D WO3 nano-layers cleaved from (001) plane of WO3 bulk crystal are stronger than those with some other 2D materials like graphene and
borophene. The electronic properties of adsorption systems such as band gaps, work functions and partial density of states were calculated and compared to the bare substrates. The results demonstrate high sensitivity and selectivity of the 2D WO3 nano-layers towards NH3, NO, HCHO, O2 and H2S. The computation of transport properties such as transmission functions and current-voltage (I-V) characteristics indicated that the presence and absence of gas molecules on the 2D WO3 nano-layers can well realize the electronic device characteristics (ON and OFF) of gas sensors. Theoretical recovery times were also calculated to estimate the reusability of the 2D
WO3 nano-layers based gas sensors. Our results suggest that the 2D WO3 nano-layers are promising candidates for sensing applications to NH3, NO, HCHO, O2 and H2S, better than graphene and borophene.
期刊:
Applied Surface Science
2021
作者:
Yang-Xin Yu,Jie Wu,Jia-Hui Li
DOI:10.1016/j.apsusc.2021.149104
Single Nb or W Atom-Embedded BP Monolayers as Highly Selective and Stable Electrocatalysts for Nitrogen Fixation with Low-Onset Potentials
Conversion of dinitrogen (N2) molecules into ammonia through electrochemical methods is a promising alternative to the traditional Haber–Bosch process. However, searching for an eligible electrocatalyst with high stability, low-onset potential, and superior selectivity is still one of the most challenging and attractive topics for the electrochemical N2 reduction reaction (NRR). Here, by means of first-principles calculations and the conductor-like screening model, four comprehensive criteria were proposed to screen out eligible NRR electrocatalysts from 29 atomic transition metals embedded on the defective boron phosphide (BP) monolayer with B-monovacancy (M/BP single-atom catalysts, SAC, M = Sc–Zn, Y–Cd, and Hf–Hg). Consequently, the Nb/BP and W/BP SACs are identified as the promising candidates, on which the N2 molecule can only be activated through the enzymatic pathway with the onset potentials of −0.25 and −0.19 V, and selectivities of 90.5 and 100%, respectively. It is worth noting that the W/BP SAC has the lowest overpotential among the 29 systems investigated. The electronic properties were also calculated in detail to analyze the activity origin. Importantly, the Nb/BP and W/BP SACs possess high thermal stabilities due to that their structures can be retained very well up to 1000 and 700 K, respectively. This work not only provides an efficient and reliable method to screen eligible NRR electrocatalysts but also paves a new way for advancing sustainable ammonia synthesis.
期刊:
ACS Applied Materials & Interfaces
2021
作者:
Yang-Xin Yu,Jia-Hui Li,Jie Wu
DOI:10.1021/acsami.0c21429
Singlet oxygen vs. triplet oxygen: functions of 2D-MoO3 catalysts in conquering catastrophic parasitic-reactions in lithium– and sodium–oxygen batteries
A 2D-MoO3 nanosheet was predicted both thermodynamically and kinetically to have functionalities to prevent singlet oxygen formation and thus increase the specific energy and cycling performance of Li– and Na–O2 cells.
期刊:
Journal of Materials Chemistry A
2021
作者:
Yang-Xin Yu,Jie Wu,Jia-Hui Li
DOI:10.1039/d1ta00699a
Toward Large-Capacity and High-Stability Lithium Storages via Constructing Quinone–2D-MnO2-Pillared Structures
Due to wide applications of lithium-ion batteries (LIBs), scientists have never stopped pursuing larger-capacity and higher-stability lithium storage materials. To obtain better LIBs, three distinct quinone−two-dimensional (2D) MnO2-pillared structures, i.e., p-benzoquinone (C6H4O2)-2D-MnO2, tetrafluoro-p-benzoquinone (C6F4O2)-2D-MnO2, and tetrachloro-p-benzoquinone (C6Cl4O2)-2D-MnO2 were designed and density functional theory calculations were employed to investigate their performance in lithium storages. The calculated theoretical capacities of C6H4O2-2D-MnO2, C6F4O2-2D-MnO2, and C6Cl4O2-2D-MnO2 are 588, 564, and 542 mAh/g,
respectively, which are all 2 times larger than that of the mesoporous MnO2. The electrochemical properties are estimated by the open-circuit voltages, which are calculated from the energies of various lithium concentrations in pillared structures. The voltage data show that the three pillared structures possess excellent characteristics for large-capacity lithium storages. Considering that lithium mobility is vital for cycling performance, the lithium diffusion paths and their energy barriers are computed. The thermal stabilities of three pristine and fully lithium-embedded systems were identified through ab initio molecular dynamics simulations at 300 K. Taken together, these results suggest that quinone−2D-MnO2-pillared structures could be prospective materials for larger and more stable lithium storages. Furthermore, our research confirms the possibility of improving lithium storages by pillar construction and provides a prospect for layered material ameliorations.
期刊:
The Journal of Physical Chemistry C
2021
作者:
Yang-Xin Yu,Jie Wu,Jia-Hui Li
DOI:10.1021/acs.jpcc.0c10211
Highly stable Mo-doped Fe2P and Fe3P monolayers as low-onset-potential electrocatalysts for nitrogen fixation
Mo atom doping can modify the electronic properties of Fe2P and Fe3P monolayers, and significantly enhance their NRR activities with onset potentials as low as −0.30 V and −0.17 V, respectively.
期刊:
Catalysis Science & Technology
2021
作者:
Yang-Xin Yu,Jia-Hui Li,Jie Wu
DOI:10.1039/d0cy02192j
Theoretical Exploration of Single-Layer Tl2O as a Catalyst in Lithium–Oxygen Battery Cathodes
Two-dimensional transition-metal oxides have been widely explored as catalysts in high-capacity nonaqueous lithium−oxygen batteries due to their excellent electrochemical performance in the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), but little attention has been paid to non-transition-metal oxides. Here, we employ density functional methods based on the Perdew−Burke−Ernzerhof (PBE) functional with dispersion correction and the Heyd−Scuseria−Ernzerhof hybrid functional (HSE06) to investigate the mechanisms of the
nucleation and decomposition processes of Li4O2(s), i.e., discharge and charge processes on single-layer Tl2O (SL-Tl2O) in lithium−oxygen batteries. HSE06 with the spin−orbital coupling effect is adopted to calculate the band gap of SL-Tl2O. It is demonstrated that the spin−orbital coupling effect is significant in predictions of not only electronic but also thermodynamic properties for heavy-element compounds such as Tl2O. The formation of LiO2(s) is initiated by the adsorption of oxygen molecules instead of lithium atoms on the surface. The intermediate reaction products strongly interact with SL-Tl2O, which causes an overpotential of 1.47 V during the electrochemical reaction. The electronic conductivity analysis of lithium oxides adsorbed on SL-Tl2O demonstrates that the electronic conductance of the layer does not change during the ORR/OER. The adsorption enthalpies of five frequently used nonaqueous solvents (tetrahydrofuran, 1,2-dimethoxyethane, 1,3-dioxolane, dimethyl carbonate, and propiolic acid) on SL-Tl2O indicate that SL-Tl2O is stable in the electrolytes. All of these calculated results indicate that SL-Tl2O is a feasible catalyst for the
ORR/OER in nonaqueous lithium−oxygen batteries.
期刊:
The Journal of Physical Chemistry C
2020
作者:
Yang-Xin Yu,Jie Wu,Jia-Hui Li
DOI:10.1021/acs.jpcc.9b09665
A Theoretical Analysis on the Oxidation and Water Dissociation Resistance on Group‐IV Phosphide Monolayers
Group-IV phosphide monolayers (MP, M=C, Si, Ge and Sn) provide a versatile platform for photocatalysts, as well as optoelectronic and nanoelectronic devices. Herein, comprehen-
sive first-principles calculations and ab initio molecular dynam-ics (AIMD) simulations were performed to explore their stabilities in the air. We identified that the MP monolayers have
excellent mechanical properties and their carrier mobilities are higher than that of phosphorene. The MP monolayers were predicted to possess superior oxidation resistance than the
boron phosphide (BP) monolayer based on the proposed donation–backdonation theory. It was observed that the dissociation and chemisorption of a water molecule on the monolayers are kinetically difficult both in the water and in oxygen–water environments involving energy barriers of 1.28–3.48 eV. We also performed AIMD simulations at 300, 1000,1200 and 1500 K. It is noteworthy that only the carbon phosphide (CP) monolayer can retain an intact structure at 1500 K, while the other three monolayers can just sustain to 1200 K. These results provide a guidance for their practical application and experimental fabrication.
期刊:
ChemPhysChem
2020
作者:
Yang-Xin Yu,Jia-Hui Li,Jie Wu
DOI:10.1002/cphc.202000766
Stabilities of group-III phosphide (MP, M = B, Al, Ga and In) monolayers in oxygen and water environments
BP monolayer is stable in a water–oxygen atmosphere, while AlP monolayer is unstable in both oxygen and water environments.
期刊:
Physical Chemistry Chemical Physics
2020
作者:
Yang-Xin Yu,Jia-Hui Li,Jie Wu
DOI:10.1039/d0cp00224k
