Liu Jiarong¹， Li Hao²

1.School of Resources， Environment and Architectural Engineering， Chifeng University， Chifeng 024000， China； 2.State Key Joint Laboratory of Environment Simulation and Pollution Control， Research Center for Eco-Environmental Sciences， Chinese Academy of Sciences， Beijing 100085， China

Abstract

Significance Sulfate is the most abundant water-soluble inorganic component of atmospheric fine particulate matter， and its formation mechanisms have long been a core issue in atmospheric pollution research. Of particular interest is why interfacial reactions proceed much faster than bulk reactions and what the underlying acceleration mechanisms are. Classical gas- and aqueous-phase frameworks describe dilute cloud water chemistry well， but they systematically underestimate sulfate production during heavy haze episodes. The gas-liquid interface provides a large reactive surface area and a unique microenvironment characterized by asymmetric solvation， strong interfacial electric fields， and ion enrichment， all of which can lower the oxidation barrier of S（IV）. In addition， although experimental techniques can locate reaction sites and measure reaction rates， they cannot capture picosecond-scale intermediates or electron-transfer dynamics. Therefore， it is of great importance to use theoretical simulations to investigate the interfacial reaction mechanisms of sulfate formation.

Progress This review systematically summarizes advances in sulfate chemistry at the gas-liquid interface， with emphasis on three research approaches： traditional experiments， in situ interfacial characterization， and theoretical calculations. It focuses on two representative pathways， namely transition metal-catalyzed oxidation and peroxide-mediated oxidation. Drawing on the authors’ long-term expertise in density functional theory， Born-Oppenheimer molecular dynamics， and machine learning potentials， it interprets key microscopic mechanisms. Multiscale simulations have revealed how interfacial electric fields， local solvation， and coordination structures govern sulfate formation kinetics， identified an additional source of explosive sulfate growth during haze， and provided a critical basis for correcting model simulation biases.

Conclusions and Prospects Sulfate， as a crucial chemical component of fine particulate matter， not only plays a pivotal role in heavy haze formation but also significantly impacts regional and global climate by regulating cloud formation and development as cloud condensation nuclei. In recent years， the rapid advancement of multiscale theoretical simulation methods， including density functional theory， first-principles molecular dynamics， and machine learning atomic potentials， has provided essential technical support for elucidating the microscopic mechanisms of sulfate formation at the molecular and electronic levels at the gas-liquid interface. This has effectively addressed the inherent limitations of traditional experimental methods in capturing transient processes and disentangling multivariable coupling effects. However， existing theoretical research still has significant limitations and cannot fully elucidate the complex coupling effects of multiple components， factors， and processes in real atmospheric aerosol systems. Numerous key scientific issues remain in methodological optimization and the mechanistic analysis of complex systems， highlighting the urgent need for more systematic and in-depth research. This paper reviews two limitations in current research on sulfate formation mechanisms. Firstly， for real multi-component atmospheric systems， machine learning methods lack sufficient generalization ability. Secondly， most studies rely on simplified single-component models and are unable to quantitatively disentangle multi-metal and multi-ligand mechanisms. Future research should focus on developing generalizable machine learning capabilities， constructing explicit interface models for multi-factor coupling， and supplementing basic dynamic parameters for atmospheric models， thereby providing a theoretical foundation for source apportionment of sulfate during haze.

Keywords： sulfate； heterogeneous reaction； formation mechanism； molecular simulation； transition metal； peroxide

Get Citation: Liu Jiarong， Li Hao. Research progress on molecular mechanisms of transition metal‑catalyzed and peroxide‑mediated pathways in sulfate aerosol formation at gas-liquid interface［J］. China Powder Science and Technology， 2027， 33（2）： 235-248.

Received：2026-08-16， Revised： 2026-09-08， Online： 2026-10-11。

Funding： The research was supported by the National Natural Science Foundation of China (Grant Nos. 22476201, 22666001, and 22206017), the Social Science Foundation of Inner Mongolia Autonomous Region of China (Grant No. 2026AY36), the Natural Science Foundation of Inner Mongolia Autonomous Region of China (Grant No. 2026MS0136), and the 15th Five-Year Plan Research Project of Educational Science in Inner Mongolia Autonomous Region of China (Grant No. NGJGH2026274).

DOI：10.13732/j.issn.1008-5548.2027.02.017

CLC No.: TB4； TQ324.8

Type Code: A

Serial No.: 1008-5548（2027）02-0235-14