A5029553936- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Molecular Spectroscopy and Structure
- Inorganic Fluorides and Related Compounds
- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Free Radicals and Antioxidants
- Catalytic Processes in Materials Science
- Catalysis and Oxidation Reactions
- Atmospheric and Environmental Gas Dynamics
- Mass Spectrometry Techniques and Applications
- MXene and MAX Phase Materials
- Air Quality Monitoring and Forecasting
- Fluorine in Organic Chemistry
- Radical Photochemical Reactions
- Air Quality and Health Impacts
- Atmospheric aerosols and clouds
- Chemical Reactions and Mechanisms
- Methane Hydrates and Related Phenomena
- Electrochemical Analysis and Applications
- Quantum, superfluid, helium dynamics
- Electron Spin Resonance Studies
- Crystallography and molecular interactions
University of Pennsylvania
2018-2025
California University of Pennsylvania
2018-2025
Robert Bosch (Germany)
2024
Temper (United States)
2024
Philadelphia University
2018-2023
Purdue University West Lafayette
2011-2022
Beijing Normal University
2022
University of Nebraska–Lincoln
2014-2020
King Saud University
2018
Lincoln College
2017
There has been considerable speculation about the role of water and complexes in chemical gas-phase reactions, including conjecture that may act as a molecular catalyst through its ability to form hydrogen bonds. Here, we present kinetic studies which effect on rate reaction between hydroxyl radicals acetaldehyde measured directly Laval nozzle expansions at low temperatures. An increasing enhancement by added was found with decreasing temperatures 300 60 kelvin. Quantum calculations...
MXenes, the new 2D transition metal carbides and nitrides, have recently attracted extensive attention due to their diverse applications excellent performances. However, thermal electrical properties of most MXene materials are yet be studied. In this work, we investigate semiconducting Sc2CT2 (T = F, OH) MXenes using first-principles calculations. Both determined show carrier mobilities. The electron mobility in Sc2CF2 is found strongly anisotropic at room temperature, with values 5.03 ×...
Single-atom catalysts (SACs) with 100% active sites have excellent prospects for application in the oxygen evolution reaction (OER). However, further enhancement of catalytic activity OER is quite challenging, particularly development stable SACs overpotentials <180 mV. Here, we report an iridium single atom on Ni2P catalyst (IrSA-Ni2P) a record low overpotential 149 mV at current density 10 mA·cm–2 1.0 M KOH. The IrSA-Ni2P delivers up to ∼28-fold higher than that widely used IrO2 1.53 V vs...
Abstract With the growing interest in low dimensional materials, MXenes have also attracted considerable attention recently. In this work, thermal and electrical properties of oxygen-functionalized M 2 CO (M = Ti, Zr, Hf) are investigated using first-principles calculations. Hf is determined to exhibit a conductivity better than MoS phosphorene. The room-temperature along armchair direction be 86.25~131.2 Wm −1 K with flake length 5~100 μm. room temperature expansion coefficient 6.094 × 10...
Abstract Designing highly active and bifunctional oxygen reduction reaction (ORR) evolution (OER) catalysts has attracted great interest toward metal–air batteries. Herein, an efficient solution to the search for MXene‐based is proposed by introducing non‐noble metals such as Fe/Co/Ni at surfaces. These results indicate that ultrahigh activities in Ni1/Ni2‐ Fe1/Ni2‐modified double‐atom (DACs) ORR/OER are better than those of well‐known unifunctional with low overpotentials, Pt(111) ORR IrO 2...
The local pH variation near the surface of CO2 reduction electrodes is important but hard to study. We develop a continuous-flow Raman electrochemical cell that enables first experimental study gas diffusion electrode under reaction conditions. At zero current, chemically reacts with 1 M KOH electrolyte at interface form HCO3- and CO32-. on cathode 7.2, concentration profile extends distance 120 μm into electrolyte, which verifies nominal overpotential from using alkaline originates Nernst...
Mo2C, the newly synthesized MXene with a large lateral size and superconductivity property, has attracted increasing interest in material science. Employing first-principles density functional calculations, its intrinsic structural, electrical, thermal, mechanical properties are investigated this work. It is found that nonmagnetic small molar volume. The electrical conductivity predicted order of 106 Ω–1m–1, value significantly influenced by doping. For thermal conductivity, both electron...
Two-dimensional (2D) materials have attracted considerable interest due to their remarkable properties and potential applications for nanoelectronics, electrodes, energy storage devices, among others. However, many well-studied 2D lack appreciable conductivity tunable mechanical strength, limiting in flexible devices. Newly developed MXenes open up the opportunity design novel conductive electronic materials. Here, using density functional theory (DFT), we investigate systematically effects...
Significance Ice growth is essential to the final shape of ice crystals; therefore, it significant relevance rich varieties practical applications and fundamental research. A correlation between surface wettability has not been established, although often forms on solid surfaces. We discover experimentally that grows along when contact angle water drops surfaces below a critical value, off above this value. Our molecular dynamics simulation analysis reveals presence/absence bilayer different...
NiFe-layered double hydroxide (LDH) is thought of as a promising bifunctional water-splitting catalyst, owing to its excellent performances for alkaline oxygen evolution reactions (OERs). However, it shows extremely poor activity toward hydrogen (HERs) due the weak adsorption. We demonstrated that integration Rh species and NiFe-LDH can dramatically improve HER kinetics without sacrificing OER performance. The were initially integrated into oxidized dopants metallic clusters (< 1 nm). In M...
Monoatomic dispersion of precious metals on the surface CeO
We present a novel mechanism for the formation of photocatalytic oxidants in deliquescent NaCl particles, which can greatly promote multiphase photo-oxidation SO2 to produce sulfate. The photoexcitation [Cl––H3O+–O2] complex leads generation Cl and OH radicals, is key reason enhancing aqueous-phase oxidation accelerating oxidation. mass normalization rate sulfate production from photoreaction on droplets could be estimated 0.80 × 10–4 μg·h–1 at 72% RH 1.33 81% RH, equivalent known O3...
Reactions of ozone with Br(-), SO(3)(2-), HSO(3)(-), I(-), and NO(2)(-), studied by stopped-flow pulsed-accelerated-flow techniques, are first order in the concentration O(3)(aq) each anion. The rate constants increase a factor 5 x 10(6) as nucleophilicities anions from Br(-) to SO(3)(2-). Ozone adducts nucleophiles proposed steady-state intermediates prior oxygen atom transfer release O(2). Ab initio calculations show possible structures for intermediates. reaction between O(3) is...
Sulfuric acid can act as a catalyst of its own formation. We have carried out computational investigation on the gas-phase formation H(2)SO(4) by hydrolysis SO(3) involving one and two water molecules, also in presence sulfuric complexes with molecules. The requires concurrence them acting catalyzer, our results predict an important catalytic effect, ranging between 3 11 kcal·mol(-1) when molecule is substituted or hydrates. In these cases, reaction products are either bare dimer complexed...
Water has a very significant impact on the processes that occur in Earth's atmosphere. is one most abundant resources our atmosphere and, because of its ability to be both hydrogen bond donor and acceptor, it can form stable complexes. The formation these complexes dramatically affect chemistry atmosphere, including heterogeneous removal alteration photochemical properties atmospheric species, water droplets aerosol particles, as well participation chemical reactions. total effects regarding...
ConspectusCloud/aerosol water surfaces exert significant influence over atmospheric chemical processes. Atmospheric processes at the surface are observed to follow mechanisms that quite different from those in gas phase. This Account summarizes our recent findings of new reaction pathways on surface. We have studied these reactions using Born–Oppenheimer molecular dynamics simulations. These studies provide useful information time scale, underlying mechanism reactions, and dynamic behavior...
Ozone–water complexes O3···(H2O)n (n = 1–4) have been theoretically investigated using QCISD and CCSD(T) methods along with the 6-311G(2df,2p), 6-311+G(2df,2p), aug-cc-pVDZ, aug-cc-pVTZ, aug-cc-pVQZ basis sets extrapolation to CBS limit. For comparison, water clusters (H2O)n also studied at same level of theory. The ozone–water are held together by a combination weak specific hydrogen-bonding van der Waals interactions. Surprisingly, hydrogen-bonded not necessarily most stable ones. In...
Understanding Criegee chemistry has become one of central topics in atmospheric research recently. The reaction intermediates with gas-phase water clusters been widely viewed as a key the troposphere. However, effect aerosols or clouds on received little attention. In this work, we have investigated between smallest intermediate, CH2OO, and gas phase, well at air/water surface using ab initio quantum chemical calculations adaptive buffered force mechanics/molecular mechanics (QM/MM) dynamics...