Publications by authors named "XiuHui Zhang"

Global iodine emissions have been increasing rapidly in recent decades, further influencing the Earth's climate and human health. However, our incomplete understanding of the iodine chemical cycle, especially the fate of higher iodine oxides, introduces substantial uncertainties into atmospheric modeling. IO was previously deemed a "dead end" in iodine chemistry; however, we provide atomic-level evidence that IO can undergo rapid air-water or air-ice interfacial reactions within several picoseconds; these reactions are facilitated by prevalent chemicals on seawater such as amines and halide ions, to produce photolabile reactive iodine species such as HOI and IX (X = I, Br, and Cl).

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The Nd-mediated coordinative chain transfer polymerization (CCTP) of dienes represents one of the state-of-the-art techniques in the current synthetic rubber field. Besides having well-controlled polymerization behaviors as well as high atom economies, it also allows for the generation of highly reactive Al-capped polydienyl chain-ends, which hold great potential, yet much less explored up to date, in achieving end functionalization to mimic the structure of natural rubber. In this study, we demonstrate an efficient in situ method to realize end-functionalizing polyisoprene by introducing epoxide compounds into a CCTP system.

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Iodic acid (IA), the key driver of marine aerosols, is widely detected within the gas and particle phases in the marine boundary layer (MBL) and even the free troposphere (FT). Although atmospheric bases like dimethylamine (DMA) and ammonia (NH) can enhance IA particles formation, their different efficiencies and spatial distributions make the dominant base-stabilization mechanisms of forming IA particles unclear. Herein, we investigated the IA-DMA-NH nucleation system through quantum chemical calculations at the DLPNO-CCSD(T)/aug-cc-pVTZ(-PP)//ωB97X-D/6-311++G(3df,3pd) + aug-cc-pVTZ-PP level of theory and cluster dynamics simulations.

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The formation of environmentally persistent free radicals (EPFRs) is mediated by the particulate matter's surface, especially transition metal oxide surfaces. In the context of current atmospheric complex pollution, various atmospheric components, such as key atmospheric oxidants ·OH and O, are often absorbed on particulate matter surfaces, forming particulate matter surfaces containing ·OH and O. This, in turn, influences EPFRs formation.

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Article Synopsis
  • New particle formation (NPF) is crucial for the global climate, influenced by iodic acid (IA), which is now found inland as well as in marine environments.
  • IA significantly promotes the clustering of land-based precursors dimethylamine (DMA) and sulfuric acid (SA), thereby increasing particle nucleation rates.
  • In iodine-rich areas of China, IA could boost these nucleation rates by over 20%, with projections indicating a potential increase of 1.5 to 50 times by 2060 due to reduced pollution, underscoring the importance of including IA in atmospheric models for accurate climate impact assessments.
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Bromine chemistry is responsible for the catalytic ozone destruction in the atmosphere. The heterogeneous reactions of sea-salt aerosols are the main abiotic sources of reactive bromine in the atmosphere. Here, we present a novel mechanism for the activation of bromide ions (Br) by O and HO in the absence of additional oxidants.

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The formation of environmentally persistent free radicals (EPFRs) is usually related to transition-metal oxides in particulate matter (PM). However, recent studies suggest that alkaline-earth-metal oxides (AEMOs) in PM also influence EPFRs formation, but the exact mechanism remains unclear. Here, density functional theory calculations were performed to investigate the formation mechanism of EPFRs by CHOH on AEMO (MgO, CaO, and BaO) surfaces and compare it with that on transition-metal oxide (ZnO and CuO) surfaces.

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We present a novel mechanism for the formation of photocatalytic oxidants in deliquescent NaCl particles, which can greatly promote the multiphase photo-oxidation of SO to produce sulfate. The photoexcitation of the [Cl-HO-O] complex leads to the generation of Cl and OH radicals, which is the key reason for enhancing aqueous-phase oxidation and accelerating SO oxidation. The mass normalization rate of sulfate production from the multiphase photoreaction of SO on NaCl droplets could be estimated to be 0.

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By seeding clouds, new particle formation (NPF) has a substantial impact on radiation balance, bio-geochemical cycles and global climate. Over oceans, both methanesulfonic acid (CHS(O)OH, MSA) and iodous acid (HIO) have been reported to be closely associated with NPF events; however, much less is known about whether they can jointly nucleate to form nanoclusters. Hence, quantum chemical calculations and Atmospheric Cluster Dynamics Code (ACDC) simulations were performed to investigate the novel mechanism of MSA-HIO binary nucleation.

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Aerosol microdroplets as microreactors for many important atmospheric reactions are ubiquitous in the atmosphere. pH largely regulates the chemical processes within them; however, how pH and chemical species spatially distribute within an atmospheric microdroplet is still under intense debate. The challenge is to measure pH distribution within a tiny volume without affecting the chemical species distribution.

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Cation exchange (CE) under mild conditions promises a facile strategy to anchor single metal sites on colloidal chalcogenides toward catalytic applications, which however has seldom been demonstrated. The dilemma behind this is the rapid kinetics and high efficiency of the reaction disfavoring atomic dispersion of the metal species. Here we report that a fine-tuning of the affinity between the incoming metal cations and the deliberately introduced ligands can be exploited to manipulate the kinetics of the CE reaction, in a quantitative and systematic manner defined by the Tolman electronic parameter of the ligands used.

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Marine aerosol formation involving iodine-bearing species significantly affects the global climate and radiation balance. Although recent studies outline the critical role of iodine oxide in nucleation, much less is known about its contribution to aerosol growth. This paper presents molecular-level evidence that the air-water interfacial reaction of IO mediated by potent atmospheric chemicals, such as sulfuric acid (HSO) and amines [e.

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Iodous acid (HIO) has been shown to play a stabilizing role in the nucleation of iodic acid (HIO) (He et al., 2021). However, the stabilization effect and specific stabilizing mechanism of HIO on HIO nucleation under different atmospheric conditions remain unclear.

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Transformation of low-volatility gaseous precursors to new particles affects aerosol number concentration, cloud formation and hence the climate. The clustering of acid and base molecules is a major mechanism driving fast nucleation and initial growth of new particles in the atmosphere. However, the acid-base cluster composition, measured using state-of-the-art mass spectrometers, cannot explain the measured high formation rate of new particles.

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Iodous acid (HIO), a vital iodine oxyacid, potentially plays an important role in the formation of new particles in marine areas (He , , 2021, , 589-595). However, the nucleation mechanism of HIO is still poorly understood. Herein, the self-nucleation of HIO under different atmospheric conditions is investigated by a combination of quantum chemical calculations and the Atmospheric Cluster Dynamics Code (ACDC) simulations.

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Environmentally persistent free radicals (EPFRs) have been recognized as harmful and persistent environmental pollutants. In polluted regions, many acidic and basic atmospheric pollutants, which are present at high concentrations, may influence the extent of the formation of EPFRs. In the present paper, density functional theory (DFT) and ab-initio molecular dynamics (AIMD) calculations were performed to investigate the formation mechanisms of EPFRs with the influence of the acidic pollutants sulfuric acid (SA), nitric acid (NA), organic acid (OA), and the basic pollutants, ammonia (A), dimethylamine (DMA) on α-AlO (0001) surface.

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Marine aerosols play an important role in the global aerosol system. In polluted coastal regions, ultra-fine particles have been recognized to be related to iodine-containing species and is more serious due to the impact of atmospheric pollutants. Many previous studies have identified iodine pentoxide (IO, IP) to be the key species in new particles formation (NPF) in marine regions, but the role of IP in the polluted coastal atmosphere is far to be fully understood.

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Aqueous zinc-ion batteries (ZIBs) are regarded as a promising candidate for ultrafast charge storage owing to the high ionic conductivity of aqueous electrolytes and high theoretical capacity of zinc metal anodes. However, the strong electrostatic interaction between high-charge-density zinc ions and host materials generally leads to sluggish ion-transport kinetics and structural collapse of rigid cathode materials during the charge/discharge process, so searching for suitable cathode materials for ultrafast and long-term stable ZIBs remains a great challenge. Herein, flexible electron-rich ion channels enabling fast-charging and stable aqueous ZIBs have been demonstrated.

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Tetranuclear CpM(CO) clusters have been synthesized for iron and vanadium but not for the intermediate first-row transition metals manganese and chromium. All of the low-energy structures of these "missing" CpM(CO) (M = Mn, Cr) species are shown by density functional theory to consist of a central M tetrahedron with each of the four faces capped by a μ-CO group. The individual low-energy structures differ in their spin states and in their formal metal-metal bond orders along the six edges of their central M tetrahedra.

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Recent research [Wang , 581, 184-189 (2020)] indicates nitric acid (NA) can participate in sulfuric acid (SA)-ammonia (NH) nucleation in the clean and cold upper free troposphere, whereas NA exhibits no obvious effects at the boundary layer with relatively high temperatures. Herein, considering that an SA-dimethylamine (DMA) nucleation mechanism was detected in megacities [Yao , 361, 278-281 (2018)], the roles of NA in SA-DMA nucleation are investigated. Different from SA-NH nucleation, we found that NA can enhance SA-DMA-based particle formation rates in the polluted atmospheric boundary layer, such as Beijing in winter, with the enhancement up to 80-fold.

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Comprehensive investigations of the possible formation pathways of sulfate, the main composition of atmospheric aerosol in marine areas, continue to challenge atmospheric chemists. As one of the most important oxidation routes of S(iv) contributing to sulfate formation, the reaction process of S(iv) oxidized by hypobromic acid, which is ubiquitous with the gas-phase mixing ratios of ∼310 ppt and has a well-known oxidative capacity, has attracted wide attention. However, little information is available about the detailed reaction mechanism.

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Secondary sulfate plays a crucial role in forming marine aerosol, which in turn is an important source of natural aerosol at a global level. Recent experimental studies suggest that oxidation of S(IV) compounds, in practice dissolved sulfur dioxide, to sulfate (S(VI)) by hypochloric acid could be one of the most significant pathways for sulfate formation in marine areas. However, the exact mechanism responsible for this process remains unknown.

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Recent research has shown the almost barrierless cycloaddition reaction of the carboxylic acid with one SO to form products with group of -OSOH, which can form stable clusters with the nucleation precursors through hydrogen bonds (Mackenzie et al., 2015, 349, 58). Oxalic acid (OA), the simplest and prevalent dicarboxylic acid, was selected as an example to clarify the possibility to react with two SO sequentially and the nucleation potential of products.

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Amino acids are recognized as significant components of atmospheric aerosols. However, their potential role in atmospheric new particle formation (NPF) is poorly understood, especially aspartic acid (ASP), one of the most abundant amino acids in the atmosphere. It has not only two advantageous carboxylic acid groups but also one amino group, both of which are both effective groups enhancing NPF.

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The effect of a single water molecule on the reaction of dimethyl sulfide (DMS) with BrO reaction has been investigated using quantum chemical calculations at the CCSD(T)/6-311++G**//BH&HLYP/aug-cc-pVTZ level of theory. Two reaction mechanisms have been considered both in the absence and the presence of water, namely, oxygen atom transfer and hydrogen abstraction, among which the oxygen atom transfer was predominant. Five reaction channels were found in the absence of water, in which the channels starting from the -configuration of the pre-reaction complexes were more favorable because of the low energy barrier.

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