Publications by authors named "Maofa Ge"

Supported Pt catalysts are often subjected to severe deactivation under the conditions of high temperature and water vapor in catalytic oxidation; thus, the superior stability and water-resistant ability of catalysts have great significance for the effective degradation of volatile organic compounds (VOCs). Herein, we constructed a Pt/CeO-N catalyst with an active interfacial perimeter, in which Pt species were partially embedded in the defective CeO-N support to prevent the sintering. A significant charge transfer between Pt species and ceria in the embedding structure occurred via the Pt-CeO interface, which induced the formation of a Pt-O-Ce interfacial structure.

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Article Synopsis
  • * A machine learning model incorporating chemical mechanisms was developed to analyze two years of urban observations, helping to assess different contributions to HONO and infer important kinetic parameters.
  • * The study found that during summer, photolysis of nitric acid on surfaces is the major daytime source of HONO, highlighting the effectiveness of machine learning in understanding atmospheric chemistry.
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Unsaturated alcohols are a class of Biogenic volatile organic compounds (BVOCs) emitted in large quantities by plants when damaged or under adverse environmental conditions, and studies on their atmospheric degradation at night are still lacking. We used chamber experiments to study the gas-phase reactions of three unsaturated alcohols, E-2-penten-1-ol, Z-2-hexen-1-ol and Z-3-hepten-1-ol, with NO radicals (NO•) during the night. The rate constants of these reactions were (11.

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Photooxidation of polycyclic aromatic hydrocarbons (PAHs), which are widely observed in atmospheric particulate matter (PM), largely determines their atmospheric fate. In the environment, PAHs are highly complex in chemical composition, and a great variety of PAHs tend to co-occur. Despite extensive investigation on the photochemical behavior of individual PAH molecules, the photochemical interaction among these coexisting PAHs is still not well understood.

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Article Synopsis
  • Biomass burning (BB) produces harmful gases and particles that affect air quality and climate, but scientists haven't focused much on chlorine emissions from this process.
  • A study from 2001 to 2018 found that Asia released a lot of chlorine from BB, especially China, Myanmar, and India, and that this can change with farming practices.
  • The research showed that burning biomass increases chlorine levels in the air, which affects other important chemicals, making BB a bigger player in air pollution than we thought.
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There is growing interest in the contribution of ultrafine particles to air quality, climate, and human health. Ultrafine particles are of central significance for the influence of radiative forcing of climate change by involving in the formation of clouds and precipitation. Moreover, exposure to ultrafine particles can enhance the disease burden.

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Oxygen vacancy engineering in transition metal oxides is an effective strategy for improving catalytic performance. Herein, defect-enriched MnO catalysts were constructed by controlling the calcination temperature. The high content of oxygen vacancies and accompanying Mn ions were generated in MnO catalysts calcined at low temperature, which could greatly improve the low-temperature reducibility and migration of surface oxygen species.

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Sulfate aerosol is one of the major components of secondary fine particulate matter in urban haze that has crucial impacts on the social economy and public health. Among the atmospheric sulfate sources, Mn(II)-catalyzed SO oxidation on aerosol surfaces has been regarded as a dominating one. In this work, we measured the reaction kinetics of Mn(II)-catalyzed SO oxidation in single droplets using an aerosol optical tweezer.

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Alkyl-PAHs (APAHs) have been identified worldwide, which could rapidly react with chlorine and OH radicals in the atmosphere. In this study, a comprehensive investigation is conducted for SOA generated by a representative alkyl-naphthalene (1-methyl naphthalene, 1-MN) initiated by Cl, including yield, chemical composition, and volatility of SOA. To better understand 1-MN atmospheric oxidation, reaction mechanisms of 1MN with Cl atoms and OH radicals are proposed and compared under different nitrogen oxides (NO) conditions.

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During the COVID-19 lockdown in the Beijing-Tianjin-Hebei (BTH) region in China, large decrease in nitrogen oxides (NO) emissions, especially in the transportation sector, could not avoid the occurrence of heavy PM pollution where nitrate dominated the PM mass increase. To experimentally reveal the effect of NO control on the formation of PM secondary components (nitrate in particular), photochemical simulation experiments of mixed volatile organic compounds (VOCs) under various NO concentrations with smog chamber were performed. The proportions of gaseous precursors in the control experiment were comparable to ambient conditions typically observed in the BTH region.

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Branched alkanes are ubiquitous in the troposphere and play an important role in the chemical processes. In this work, the rate constants and products for the reaction of Cl atoms with 3-methylhexane and 2-methylheptane were measured at room temperature (298 ± 0.2 K) and atmospheric pressure using a conventional relative rate method.

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Peroxyacetyl nitrate (PAN) is a typical secondary photochemical product in the atmospheric environment with significant adverse effects on human health and plant growth. In this study, PAN and other pollutants, as well as meteorological conditions were observed intensively from August to September in 2022 at a typical urban sampling site in Beijing, China. The mean and maximum PAN concentrations during the observation period were 1.

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Nitrous acid (HONO) is an established precursor of hydroxyl (OH) radical and has significant impacts on the formation of PM and O. Despite extensive research on HONO observation in recent years, knowledge regarding its sources and sinks in urban areas remains inadequate. In this study, we monitored the atmospheric concentrations of HONO and related pollutants, including gaseous nitric acid and particulate nitrate, simultaneously at a supersite in downtown Chengdu, a megacity in southwestern China during spring, when was chosen due to its tolerance for both PM and O pollution.

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Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the "air pollution complex" was first proposed by Professor Xiaoyan TANG in 1997. For papers published in 2021 on air pollution (only papers included in the Web of Science Core Collection database were considered), more than 24 000 papers were authored or co-authored by scientists working in China. In this paper, we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years, including studies on (1) sources and emission inventories, (2) atmospheric chemical processes, (3) interactions of air pollution with meteorology, weather and climate, (4) interactions between the biosphere and atmosphere, and (5) data assimilation.

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Secondary air pollutants, originating from gaseous pollutants and primary particulate matter emitted by natural sources and human activities, undergo complex atmospheric chemical reactions and multiphase processes. Secondary gaseous pollutants represented by ozone and secondary particulate matter, including sulfates, nitrates, ammonium salts, and secondary organic aerosols, are formed in the atmosphere, affecting air quality and human health. This paper summarizes the formation pathways and mechanisms of important atmospheric secondary pollutants.

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Atmospheric nanoparticles are crucial components contributing to fine particulate matter (PM), and therefore have significant effects on visibility, climate, and human health. Due to the unique role of atmospheric nanoparticles during the evolution process from gas-phase molecules to larger particles, a number of sophisticated experimental techniques have been developed and employed for online monitoring and characterization of the physical and chemical properties of atmospheric nanoparticles, helping us to better understand the formation and growth of new particles. In this paper, we firstly review these state-of-the-art techniques for investigating the formation and growth of atmospheric nanoparticles (e.

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The atmospheric chemistry of nitrous acid (HONO) has received extensive attention because of its significant contribution to hydroxyl (OH) radicals. Heterogeneous reaction of NO is an important HONO source, and its reaction mechanism is affected by many factors, such as concentration of gaseous NO, surface adsorbed water, relative humidity and temperature. Although laboratory studies have confirmed the effect of temperature on heterogeneous reaction of NO, there are few field observations reporting about it.

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Atmospheric oxidizing capacity (AOC) is the fundamental driving factors of chemistry process (e.g., the formation of ozone (O) and secondary organic aerosols (SOA)) in the troposphere.

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Organosulfates (OSs) are well-known and ubiquitous constituents of atmospheric aerosol particles and have been used as secondary organic aerosol markers in many field studies. Hence, it is imperative to understand the formation of OS species in the atmosphere. Recently, hydroxy acids (HAs) and hydroxy acid sulfates have been extensively detected in the atmospheric environment.

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Article Synopsis
  • - Atmospheric trace metals, crucial for understanding air quality and their effects on human health, need a reliable method for measuring their soluble fraction, which indicates bioavailability and chemical reactivity.
  • - A study conducted in Central China explored different solvents to find the best method for assessing this soluble fraction of trace metals and how it changes with various levels of pollution.
  • - Results revealed that more acidic solvents provided better measurements and highlighted that higher pollution levels correlate with an increased soluble fraction, leading to greater health risks during heavy haze conditions.
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Severe winter haze events in Beijing and North China Plain are characterized by rapid production of sulfate aerosols with unresolved mechanisms. Oxidation of SO by O in the absence of metal catalysts (uncatalyzed autoxidation) represents the most ubiquitous SO conversion pathway in the atmosphere. However, this reaction has long been regarded as too slow to be atmospherically meaningful.

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There is a large gap between the simulated and observed sulfate concentrations during winter haze events in North China. Although multiphase sulfate formation mechanisms have been proposed, they have not been evaluated using chemical transport models. In this study, the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) was used to apportion sulfate formation.

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The field observation of 54 non-methane hydrocarbon compounds (NMHCs) was conducted from September 1 to October 20 in 2020 during autumn in Haidian District, Beijing. The mean concentration of total NMHCs was 29.81 ± 11.

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New particle formation (NPF) is the primary source of nanoparticles and contributes a large number of concentrations of cloud condensation nuclei. In recent years, field campaigns and laboratory experiments have been conducted to promote cognition of the mechanism for NPF and its following growth processes. The chemical composition measurement of nanoparticles could help deepen understanding of the initial step of particulate matter formation.

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As a representative species of intermediate volatile organic compounds (IVOCs), long-chain alkanes are considered to be important precursors of secondary organic aerosols (SOA) in the atmosphere. This work reviews the previous studies on long-chain alkanes in the atmosphere: (1) the detection methods and filed observations of long-chain alkanes in both gas and particle phases are summarized briefly; (2) the laboratory studies of long chain alkanes are reviewed, the kinetic data, reaction mechanism, SOA yields, and physicochemical properties of SOA are included in detail; (3) the research progress related to model simulations of long-chain alkanes are also discussed. In addition, based on available research results, several perspective contents are proposed that can be used as a guideline for future research plans.

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