scholarly journals Condensing water vapor to droplets generates hydrogen peroxide

2020 ◽  
Vol 117 (49) ◽  
pp. 30934-30941
Author(s):  
Jae Kyoo Lee ◽  
Hyun Soo Han ◽  
Settasit Chaikasetsin ◽  
Daniel P. Marron ◽  
Robert M. Waymouth ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Water Vapor ◽  
Electric Field ◽  
Water Oxidation ◽  
Time Course ◽  
Strong Electric Field ◽  
Bulk Water ◽  
Air Interface ◽  
Heterogeneous Interfaces ◽  
Electrical Bias

It was previously shown [J. K. Leeet al.,Proc. Natl. Acad. Sci. U.S.A., 116, 19294–19298 (2019)] that hydrogen peroxide (H2O2) is spontaneously produced in micrometer-sized water droplets (microdroplets), which are generated by atomizing bulk water using nebulization without the application of an external electric field. Here we report that H2O2is spontaneously produced in water microdroplets formed by dropwise condensation of water vapor on low-temperature substrates. Because peroxide formation is induced by a strong electric field formed at the water–air interface of microdroplets, no catalysts or external electrical bias, as well as precursor chemicals, are necessary. Time-course observations of the H2O2production in condensate microdroplets showed that H2O2was generated from microdroplets with sizes typically less than ∼10 µm. The spontaneous production of H2O2was commonly observed on various different substrates, including silicon, plastic, glass, and metal. Studies with substrates with different surface conditions showed that the nucleation and the growth processes of condensate water microdroplets govern H2O2generation. We also found that the H2O2production yield strongly depends on environmental conditions, including relative humidity and substrate temperature. These results show that the production of H2O2occurs in water microdroplets formed by not only atomizing bulk water but also condensing water vapor, suggesting that spontaneous water oxidation to form H2O2from water microdroplets is a general phenomenon. These findings provide innovative opportunities for green chemistry at heterogeneous interfaces, self-cleaning of surfaces, and safe and effective disinfection. They also may have important implications for prebiotic chemistry.

scholarly journals The Impact of the Electric Field on Surface Condensation of Water Vapor: Insight from Molecular Dynamics Simulation

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 64 ◽  
Author(s):  
Qin Wang ◽  
Hui Xie ◽  
Zhiming Hu ◽  
Chao Liu
Keyword(s):  
Molecular Dynamics ◽  
Water Vapor ◽  
Electric Field ◽  
Intermolecular Forces ◽  
Dynamics Simulation ◽  
Water Molecules ◽  
Attraction Force ◽  
Condensation Rate ◽  
Shape Transformation ◽  
The Impact

In this study, molecular dynamics simulations were carried out to study the coupling effect of electric field strength and surface wettability on the condensation process of water vapor. Our results show that an electric field can rotate water molecules upward and restrict condensation. Formed clusters are stretched to become columns above the threshold strength of the field, causing the condensation rate to drop quickly. The enhancement of surface attraction force boosts the rearrangement of water molecules adjacent to the surface and exaggerates the threshold value for shape transformation. In addition, the contact area between clusters and the surface increases with increasing amounts of surface attraction force, which raises the condensation efficiency. Thus, the condensation rate of water vapor on a surface under an electric field is determined by competition between intermolecular forces from the electric field and the surface.

scholarly journals Axion assisted Schwinger effect

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Valerie Domcke ◽  
Yohei Ema ◽  
Kyohei Mukaida
Keyword(s):  
Electric Field ◽  
Production Rate ◽  
Strong Electric Field ◽  
Background Field ◽  
Chiral Anomaly ◽  
Fermion Mass ◽  
Anomaly Equation ◽  
Electric And Magnetic Fields ◽  
Schwinger Effect ◽  
Momentum Transverse

Abstract We point out an enhancement of the pair production rate of charged fermions in a strong electric field in the presence of time dependent classical axion-like background field, which we call axion assisted Schwinger effect. While the standard Schwinger production rate is proportional to $$ \exp \left(-\pi \left({m}^2+{p}_T^2\right)/E\right) $$ exp − π m 2 + p T 2 / E , with m and pT denoting the fermion mass and its momentum transverse to the electric field E, the axion assisted Schwinger effect can be enhanced at large momenta to exp(−πm2/E). The origin of this enhancement is a coupling between the fermion spin and its momentum, induced by the axion velocity. As a non-trivial validation of our result, we show its invariance under field redefinitions associated with a chiral rotation and successfully reproduce the chiral anomaly equation in the presence of helical electric and magnetic fields. We comment on implications of this result for axion cosmology, focussing on axion inflation and axion dark matter detection.

scholarly journals Overcoming the water oxidative limit for ultra-high-workfunction hole-doped polymers

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qi-Mian Koh ◽  
Cindy Guanyu Tang ◽  
Mervin Chun-Yi Ang ◽  
Kim-Kian Choo ◽  
Qiu-Jing Seah ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
Water Oxidation ◽  
Soft Materials ◽  
Bulk Water ◽  
Oxidation Potential ◽  
Doped Semiconductors ◽  
Good Thermal Stability ◽  
Doped Polymers ◽  
Super Acid ◽  
Maximum Work

AbstractIt is widely thought that the water-oxidation reaction limits the maximum work function to about 5.25 eV for hole-doped semiconductors exposed to the ambient, constrained by the oxidation potential of air-saturated water. Here, we show that polymer organic semiconductors, when hole-doped, can show work functions up to 5.9 eV, and yet remain stable in the ambient. We further show that de-doping of the polymer is not determined by the oxidation of bulk water, as previously thought, due to its general absence, but by the counter-balancing anion and its ubiquitously hydrated complexes. The effective donor levels of these species, representing the edge of the ‘chemical’ density of states, can be depressed to about 6.0 eV below vacuum level. This can be achieved by raising the oxidation potential for hydronium generation, using large super-acid anions that are themselves also stable against oxidation. In this way, we demonstrate that poly(fluorene-alt-triarylamine) derivatives with tethered perfluoroalkyl-sulfonylimidosulfonyl anions can provide ambient solution-processability directly in the ultrahigh-workfunction hole-doped state to give films with good thermal stability. These results lay the path for design of soft materials for battery, bio-electronic and thermoelectric applications.

Observation of the Avalanche of Runaway Electrons in Air in a Strong Electric Field

2012 ◽  
Vol 109 (8) ◽  
Author(s):  
A. V. Gurevich ◽  
G. A. Mesyats ◽  
K. P. Zybin ◽  
M. I. Yalandin ◽  
A. G. Reutova ◽  
...  
Keyword(s):  
Electric Field ◽  
Strong Electric Field ◽  
Runaway Electrons

Electric-Field Induced Formation of Superconducting Granular Balls

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2529-2535
Author(s):  
R. Tao ◽  
X. Xu ◽  
Y. C. Lan
Keyword(s):  
Surface Energy ◽  
Electric Field ◽  
Liquid Nitrogen ◽  
Applied Electric Field ◽  
Strong Electric Field ◽  
Particle Surface ◽  
Cooper Pairs ◽  
Surface Charges

When a strong electric field is applied to a suspension of micron-sized high T c superconducting particles in liquid nitrogen, the particles quickly aggregate together to form millimeter-size balls. The balls are sturdy, surviving constant heavy collisions with the electrodes, while they hold over 106 particles each. The phenomenon is a result of interaction between Cooper pairs and the strong electric field. The strong electric field induces surface charges on the particle surface. When the applied electric field is strong enough, Cooper pairs near the surface are depleted, leading to a positive surface energy. The minimization of this surface energy leads to the aggregation of particles to form balls.

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