Surfaces and interfaces play key roles in chemical and material science. Understanding physical and chemical processes at complex surfaces and interfaces is a challenging task. Machine learning provides a powerful tool to help analyze and accelerate simulations. This comprehensive review affords an overview of the applications of machine learning in the study of surfaces and interfaces of chemical systems and materials. We categorize surfaces and interfaces into the following broad categories: solid–solid interface, solid–liquid interface, liquid–liquid interface, surface of solid, surface of liquid, and three-phase interfaces. High-throughput screening, combined machine learning and first-principles calculations, and machine learning force field accelerated molecular dynamics simulations are used to rational design and study physical and chemical processes of surfaces and interfaces in systems such as all-solid-state batteries, solar cells, and heterogeneous catalysis. This review provides detailed and comprehensive information on the applications of machine learning on surfaces and interfaces for chemical and material science.

The formation mechanisms of hydrogen peroxide due to the interaction of oxygen atom from the cold atmospheric plasmas in contact with water are not fully understood. Previous work on molecular dynamics (MD) simulations of interactions of O atoms in bulk water based on reactive force field and density-functional tight-binding method did not observe the formation of H 2 O 2 . In this work we applied density functional theory in MD simulations of 192 trajectories considering 63 H 2 O − O system to explore the reaction mechanisms for atomic oxygen radical in water. Our calculations revealed that triplet (ground) state oxygen was not reactive. Oxywater-similar structure O − O H 2 was a transient product. Perhydroxyl anion O − O H − and its counterpart hydronium H 3 O + were formed. In most of simulated cases, hydrogen peroxide was observed as a final product. The formation pathways of hydrogen peroxide exhibited large complexities for the simple hydrogen bonded system. According to the sources and pathways of the hydrogen atom being bonded in hydrogen peroxide molecule, mechanisms can be classified into (1) hydrogen-abstraction, (2) hydrogen-transfer n (n = 3, 4, 5, 6, 7, 8), (3) proton-delivery n = 2, 3, (4) proton-transfer. It was confirmed that for correct prediction of reaction mechanisms is better to use quantum molecular dynamic simulations.

In this study, the additional force generated at the gas–liquid interface by a nanosecond-pulsed needle-ring electrode atmospheric pressure plasma jet (APPJ) and its impact on the activation performance of plasma-activated water (PAW) are investigated. The mechanism of APPJ interaction at the gas–liquid interface is thoroughly examined, and the effect of discharge intensity on PAW activation is explored by measuring the gas temperature and the reactive species in the gas phase. The gas-phase characteristics of APPJ are characterized using both electrical and optical properties, while reactive substances in PAW, such as H2O2, NO2−, and NO3−, are detected using the colorimetric method. The results reveal that the interaction of APPJ with the liquid surface can be linked to rapid plasma “bullets” impacting the surface, creating an additional force that facilitates the formation of a gas–liquid plasma channel. Empirical formulas derived from the study indicate that this force is closely related to the energy of the plasma bullets and is significantly influenced by the discharge intensity. Enhanced discharge intensity markedly increases the gas temperature and the reactive species in the gas phase. Variations in these factors, induced by changing discharge intensity, are responsible for the changes in the concentration of long-lived reactive substances in the liquid phase. Among the factors studied, discharge voltage exerts a more pronounced effect than discharge frequency.

A noninvasive method was developed to measure the electrical potential in an atmospheric pressure plasma jet. The spatiotemporal evolution of electrical potential was measured by a wire electrode in experiment and simulated by a two-dimensional self-consistent numerical model, which demonstrates that the electrical potential along with the traveling ionization wave outside the discharge tube in ambient air plays a significant role on the propagation of ionization wave. It furtherly shows that the enhancement and restriction of ionization wave propagation are dependent on the amplitude of electrical potential on the auxiliary electrode, which proposes the way to manipulate the propagation of ionization wave in atmospheric pulsed discharge plasma jet.