Mercury Oxidation Research Articles

Copper-ceria catalysts with improved water and sulfur resistance: Computational design and structural optimization

Copper species dispersed on ceria have emerged as promising catalysts for various energy and environmental applications. However, the presence of water vapor in the actual application environment can significantly hinder the catalyst activity. Flame-synthesized catalysts have been found to possess good water resistance as well as strong mercury oxidation and sulfur resistance. In this study, two types of copper-cerium binary structures were compared: Cu/CeO2 and CuO/CeO2, which represent highly dispersed copper on the CeO2 lattice surface (the main structure of the flame-synthesized catalyst) and CuO clusters supporting on the CeO2 lattice (the main structure of catalyst synthesized by impregnation methods), respectively. The adsorption energies of SO2, H2O, and Hg0 over these structures were studied by density functional theory calculations. The results revealed that Cu-O2/CeO2 (Cu/CeO2 with absorbed O2) had the highest Hg0 adsorption energy (−81.4 kJ/mol), followed by CuO/CeO2 (−13.1 kJ/mol) and CeO2 (−4.4 kJ/mol). Both Cu-O2/CeO2 and CuO/CeO2 showed improved sulfur resistance compared to CeO2, because SO2 was preferentially absorbed on copper sites, protecting the active sites on the CeO2 surface·H2O was absorbed and hydrolyzed into hydroxyl groups on the surfaces of all structures. The hydrolysis process consumed active oxygen on the CeO2 surface for CeO2 and CuO/CeO2, but consumed oxygen absorbed from the surrounding air for Cu-O2/CeO, leading to its best water resistance among the three. This finding opens up possibilities for the development of highly efficient and water-resistant catalysts.

Dissolution Potential of Elemental Mercury in the Presence of Bisulfide and Implications for Mobilization.

Liquid elemental mercury (Hg0L) pollution can remain in soils for decades and, over time, will undergo corrosion, a process in which the droplet surface oxidizes soil constituents to form more reactive phases, such as mercury oxide (HgO). While these reactive coatings may enhance Hg migration in the subsurface, little is known about the transformation potential of corroded Hg0L in the presence of reduced inorganic sulfur species to form sparingly soluble HgS particles, a process that enables the long-term sequestration of mercury in soils and generally reduces its mobility and bioavailability. In this study, we investigated the dissolution of corroded Hg0L in the presence of sulfide by quantifying rates of aqueous Hg release from corroded Hg0L droplets under different sulfide concentrations (expressed as the S:Hg molar ratio). For droplets corroded in ambient air, no differences in soluble Hg release were observed among all sulfide exposure levels (S:Hg mole ratios ranging from 10-4 to 10). However, for droplets oxidized in the presence of a more reactive oxidant (hydrogen peroxide, H2O2), we observed a 10- to 25-fold increase in dissolved Hg when the oxidized droplets were exposed to low sulfide concentrations (S:Hg ratios from 10-4 to 10-1) relative to droplets exposed to high sulfide concentrations. These results suggest two critical factors that dictate the release of soluble Hg from Hg0L in the presence of sulfide: the extent of surface corrosion of the Hg0L droplet and sufficient sulfide concentration for the formation of HgS solids. The mobilization of Hg0L in porous media, therefore, largely depends on aging conditions in the subsurface and chemical reactivity at the Hg0L droplet interface.

Fabrication of BiOIO3/g-C3N4/Er3+ containing oxygen vacancies for photocatalytic oxidation of gaseous elemental mercury

Construction of heterojunction and formation of oxygen vacancy are effective methods to improve the performance of photocatalysts. In this work, Er3+-doped BiOIO3/g-C3N4 photocatalyst with oxygen-rich vacancies was prepared by a simple hydrothermal and calcination method for the photocatalytic oxidation of elemental mercury. The structural properties of BiOIO3/g-C3N4/Er3+ were analyzed by XRD, SEM and BET. The results showed that all samples exhibited good photocatalytic oxidation ability for Hg0 under visible light irradiation. Among them, the photocatalyst with Er3+-doped BiOIO3/g-C3N4 and then calcined has the highest removal efficiency of Hg0, which is 68.83%. This may be due to the increase of oxygen vacancy caused by Er3+ doping, which enables the photocatalyst to have higher electron transfer rate and wider visible light absorption range. Finally, the possible mechanism of photocatalytic oxidation of gaseous elemental mercury with BiOIO3/g-C3N4/Er3+ photocatalyst was proposed. This study provides some reference for the design and application of photocatalysts containing oxygen vacancies.

Experimental study on the photocatalytic oxidation of mercury in flue gas with a nano-flowered photocatalyst

To solve the scientific problem of efficient removal of singlet mercury from coal combustion flue gas, we propose to combine it with photocatalytic technology. We have successfully synthesized a novel photocatalytic material by growing iron oxide nanoparticles in situ on the surface of bismuth tungstate material and analyzed the physicochemical properties, chemical composition, morphological structure, and optical properties of the material by XRD, SEM, TEM, EPR, and UV characterization methods. Heterojunctions and oxygen vacancies were constructed to achieve efficient photocatalytic oxidative removal of singlet mercury. The mechanism of action of the enhanced photocatalytic performance is described to provide a feasible solution for the future preparation of photocatalytic materials with high catalytic activity.

Modelling the coupled mercury-halogen-ozone cycle in the central Arctic during spring

Near-surface mercury and ozone depletion events occur in the lowest part of the atmosphere during Arctic spring. Mercury depletion is the first step in a process that transforms long-lived elemental mercury to more reactive forms within the Arctic that are deposited to the cryosphere, ocean, and other surfaces, which can ultimately get integrated into the Arctic food web. Depletion of both mercury and ozone occur due to the presence of reactive halogen radicals that are released from snow, ice, and aerosols. In this work, we added a detailed description of the Arctic atmospheric mercury cycle to our recently published version of the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem 4.3.3) that includes Arctic bromine and chlorine chemistry and activation/recycling on snow and aerosols. The major advantage of our modelling approach is the online calculation of bromine concentrations and emission/recycling that is required to simulate the hourly and daily variability of Arctic mercury depletion. We used this model to study coupling between reactive cycling of mercury, ozone, and bromine during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) spring season in 2020 and evaluated results compared to land-based, ship-based, and remote sensing observations. The model predicts that elemental mercury oxidation is driven largely by bromine chemistry and that particulate mercury is the major form of oxidized mercury. The model predicts that the majority (74%) of oxidized mercury deposited to land-based snow is re-emitted to the atmosphere as gaseous elemental mercury, while a minor fraction (4%) of oxidized mercury that is deposited to sea ice is re-emitted during spring. Our work demonstrates that hourly differences in bromine/ozone chemistry in the atmosphere must be considered to capture the springtime Arctic mercury cycle, including its integration into the cryosphere and ocean.

Three-dimensional porous CuO-modified CeO2-Al2O3 catalysts with chlorine resistance for simultaneous catalytic oxidation of chlorobenzene and mercury: Cu-Ce interaction and structure

Chlorine poisoning effects are still challenging to develop efficient catalysts for applications in chlorobenzene (CB) and mercury (Hg0) oxidation. Herein, three-dimensional porous CuO-modified CeO2-Al2O3 catalysts with macroporous framework and mesoporous walls prepared via a dual template method were employed to study simultaneous oxidation of CB and Hg0. CuO-modified CeO2-Al2O3 catalysts with three-dimensional porous structure exhibited outstanding activity and stability for simultaneous catalytic oxidation of CB and Hg0. The results demonstrated that the addition of CuO into CeO2-Al2O3 can simultaneously enhance the acid sites and redox properties through the electronic inductive effect between CuO and CeO2 (Cu2++Ce3+↔Cu++Ce4+). Importantly, the synergistic effect between Cu and Ce species can induce abundant oxygen vacancies formation, produce more reactive oxygen species and facilitate oxygen migration, which is beneficial for the deep oxidation of chlorinated intermediates. Moreover, macroporous framework and mesoporous nanostructure dramatically improved the specific surface area for enhancing the contact efficiency between reactants and active sites, leading to a remarkable decrease of byproducts deposition. CB and Hg0 had function of mutual promotion in this reaction system. In tune with the experimental results, the possible mechanistic pathways for simultaneous catalytic oxidation of CB and Hg0 were proposed.

A rare case of tertiary nasal syphilis: an unusual ear, nose, and throat manifestation of a rare disease

Tertiary syphilis is a rare entity in present antibiotic era. Syphilis of the nose is considered to be very rare by all authorities. It is mainly a systemic disease caused by the spirochete Treponema pallidum. The infection acquired may be congenital or acquired. Tertiary syphilis shows most marked manifestations in nose, causing superficial and deep ulcerations, and gumma. Nasal septum, especially the junction of the cartilaginous with the bony septum resulting in perforation is a usual manifestation. In cases where the bony septum is involved, existence of syphilis is unquestionable. The nasal deformity results from destruction of bony framework of nose and shrinking of fibroid tissue, thus, produces the typical saddle nose which is characteristic of syphilis. The treatment line for syphilis has remained relatively unchanged in recent years and continues to vary with stage of infection. However, local treatment consists of clearance of crusts and regular cleansing of the nasal passages by copious alkaline douches. Yellow mercury oxide ointment may be applied locally. The purpose of local treatment is to remove the discharge and crusts, kill spirochetes, promote wound healing and epithelial growth, prevent secondary infection.

Theoretical insight into the influence of SO2 on the adsorption and oxidation of mercury over the MnO2 surface

The inferior sulfur resistance is a major technical bottleneck of Mn-based catalysts to be employed as low-temperature selective catalytic reduction (SCR) catalyst for elemental mercury (Hg0) oxidation. The first-principle calculation based on density functional theory was adopted to investigate the influence of SO2 on mercury adsorption and oxidation over the MnO2 surface. The results indicated that Hg0 preferred to adsorb at the hollow and Obr bridge sites on the surface, and the adsorption of HgO was a strong chemisorption behavior. SO2 could be retained on the MnO2 surface through chemisorption. The adsorbed SO2 generated inhibition on Hg0 adsorption by the competitive and repulsive effects, while the effect of SO2 on HgO adsorption was negligible. SO2 showed almost no impact on the adsorption and dissociation of O2. Hg0 adsorption and oxidation at the active sites adjacent to the adsorbed SO2 was apparently restrained on the SO2-covered surface, and the desorption of generated HgO became easier compared to that on the clean surface. By contrast, Hg0 oxidation at the nonadjacent sites to SO2 was little influenced by the adsorbed SO2. The study results would offer guidance for impairing the inhibitory effect of SO2 and improving the SO2 resistance of Mn-based catalysts.

Study on the elution mechanism of HgO on mercury-loaded adsorbent in KCl solution via temperature programmed desorption (TPD) method

MnTi adsorbent prepared by precipitation method was used to remove elemental mercury in pure nitrogen atmosphere, and TPD method was employed to investigate the mechanism of mercury elution from mercury-loaded MnTi adsorbent in KCl solution. In the gas-phase mercury adsorption process, the MnTi adsorbent removed mercury with a high efficiency of 50% under pure nitrogen atmosphere. The effects of stirring time, eluent concentration, and pH on Hg elution efficiency were evaluated in the liquid-phase Hg elution process. Mercury elution was assisted by adequate stirring time and eluent concentration. The pH value of the environment influenced mercury elution, with an acidic environment being more effective for mercury oxide elution. According to the experimental results, the highest mercury elution efficiency of 0.5 M KCl solution was 79%. The active chlorine produced during the elution process was valuable for reuse. The mercury removal performance of the reused MnTi adsorbent was not significantly different from that of the fresh adsorbent. The elution mechanism of HgO was also proposed, with the key link being the reaction of HgO(red) in solution with excess Cl− to form [HgCl4]2− complexes, which then entered the liquid phase. It was possible to conclude that KCl solution had a high potential for mercury elution from mercury-carrying adsorbents and waste adsorbent reuse.

Source mechanisms and transport patterns of tropospheric bromine monoxide: findings from long-term multi-axis differential optical absorption spectroscopy measurements at two Antarctic stations

Abstract. The presence of reactive bromine in polar regions is a widespread phenomenon that plays an important role in the photochemistry of the Arctic and Antarctic lower troposphere, including the destruction of ozone, the disturbance of radical cycles, and the oxidation of gaseous elemental mercury. The chemical mechanisms leading to the heterogeneous release of gaseous bromine compounds from saline surfaces are in principle well understood. There are, however, substantial uncertainties about the contribution of different potential sources to the release of reactive bromine, such as sea ice, brine, aerosols, and the snow surface, as well as about the seasonal and diurnal variation and the vertical distribution of reactive bromine. Here we use continuous long-term measurements of the vertical distribution of bromine monoxide (BrO) and aerosols at the two Antarctic sites Neumayer (NM) and Arrival Heights (AH), covering the periods of 2003–2021 and 2012–2021, respectively, to investigate how chemical and physical parameters affect the abundance of BrO. We find the strongest correlation between BrO and aerosol extinction (R=0.56 for NM and R=0.28 for AH during spring), suggesting that the heterogeneous release of Br2 from saline airborne particles (blowing snow and aerosols) is a dominant source for reactive bromine. Positive correlations between BrO and contact time of air masses, both with sea ice and the Antarctic ice sheet, suggest that reactive bromine is not only emitted by the sea ice surface but by the snowpack on the ice shelf and in the coastal regions of Antarctica. In addition, the open ocean appears to represent a source for reactive bromine during late summer and autumn when the sea ice extent is at its minimum. A source–receptor analysis based on back trajectories and sea ice maps shows that main source regions for BrO at NM are the Weddell Sea and the Filchner–Ronne Ice Shelf, as well as coastal polynyas where sea ice is newly formed. A strong morning peak in BrO frequently occurring during summer and that is particularly strong during autumn suggests a night-time build-up of Br2 by heterogeneous reaction of ozone on the saline snowpack in the vicinity of the measurement sites. We furthermore show that BrO can be sustained for at least 3 d while travelling across the Antarctic continent in the absence of any saline surfaces that could serve as a source for reactive bromine.

Mitigating potential public health risks and challenges from hazardous materials contained in electronic waste items in a developing country setting.

Sustainable Development Goals (SDGs) Targets 12.4 and 3.9 aim to reduce deaths and illnesses from hazardous chemicals and to achieve environmentally friendly management of chemical and wastes. Electronic wastes, which contain hazardous chemicals, are rapidly generated in poor countries due to demand for affordable near-end-of-life internet-enabled gadgets that soon wear out and are improperly disposed due to ignorance, throw-away mentality and dearth of waste management infrastructure. This study identified hazardous chemicals contained in significant quantities in e-waste items, described their public health challenges and suggested mitigation measures. Results showed that mercury, polychlorinated biphenyls (PCBs), cadmium, lead and beryllium oxide were hazardous chemicals contained in significant quantities in e-waste items. The study recommended the formulation of appropriate environmental health education technology policy (AEHETP) to guide stakeholders to design education, preventive, therapeutic and decontamination plans for awareness creation and raising to address the toxic effects of e-waste items on users in poor countries.

Insight into the sulfur resistance of OMS-2 modified with iron for mercury oxidation

To improve the sulfur resistance of manganese oxide octahedral molecular sieve (OMS-2) for Hg0 oxidation, OMS-2 modified by iron (Fex-OMS-2) is prepared through hydrothermal synthesis method in this study, and their Hg0 removal performance and sulfur resistance were tested in simulate flue gas. Hg0 removal efficiency of Fe0.05-OMS-2 can reach 98 % at 150 °C. Its mercury removal efficiency remains 89.2 % even in the presence of 1500 ppm SO2, while the value of OMS-2 under the same condition is only 54 %. Characterization results show that Fe0.05-OMS-2 has spinel structure with Fe2O3 wrapped on the catalyst surface which is (Mn0.983Fe0.017)2O3. Its active components both contain iron oxide and manganese oxide, which forms a double active center. Iron oxide on the catalyst surface can compete with manganese oxide for SO2 adsorption and further forms FeSO4, thus, inhibiting the sulfation of active manganese oxide and improving its sulfur resistance. Additionally, Fe0.05-OMS-2 exhibit strong water resistance, and Hg0 removal efficiency is nearly no change after the addition of 8 % H2O in the simulated flue gas.

Spontaneous adsorption–oxidation of gaseous elemental mercury via a conjugated unit –NH+˙–Cl*: creation and mechanisms

A Cl-doped protonated polyaniline-coated multiwall carbon nanotube (Cl-PANI+@MWCNT) composite provides a new method for the spontaneous adsorption–oxidation of gaseous elemental mercury.

Three-Dimensional Porous Cuo-Modified Ceo2-Al2o3 Catalysts with Chlorine Resistance for Simultaneous Catalytic Oxidation of Chlorobenzene and Mercury: Cu-Ce Interaction and Structure

Three-Dimensional Porous Cuo-Modified Ceo2-Al2o3 Catalysts with Chlorine Resistance for Simultaneous Catalytic Oxidation of Chlorobenzene and Mercury: Cu-Ce Interaction and Structure

The mechanism of Hager's test for glucose

There are several colour tests for glucose detection, not being the case for glucose estimation. Thus, the quantitative test for glucose due to Hager is fairly important. The test is based on an oxido-reduction process. It employs mercury oxide, sodium chloride, and sodium acetate in a slightly acidic medium (2.5% acetic acid). In the presence of glucose, this reagent precipitates the very insoluble dimercury dichloride which is related to glucose content and concentration. Since the reaction route has not been described, and less the reaction mechanism, both are provided in this communication. Each step is fully commented and the electron flow is given. The reactive intermediate is H-O-Hg+ which reacts with nucleophilic species. This way hydroxymercury glucose-enolate is formed, as well as, chloromercury hydroxide. Protolysis of both intermediates and reaction with chloride ions gives the two key intermediates, chloromercury glucose-enolate and the cation Cl-Hg+. A bimolecular reaction between these intermediates occurs via a concerted mechanism (redox reaction). The oxidation product is 2-ketoglucose (glucosone), whereas the reduced compound is dimercury dichloride.

Cu-CeO2 nanorings with abundant oxygen vacancies for superior catalytic oxidation

Ceria (CeO2) catalysts with different structures and shapes usually exhibit significant variations in catalytic activity. In this work, copper-doped CeO2 (Cu-CeO2) nanorings with abundant oxygen vacancies were synthesized by a Cu induced self-assemble method via hydrothermal process. The formation process of Cu-CeO2 investigated by TEM and XRD showed that the introduction of Cu dopants was critical to the formation of unique nanorings structure. The catalytic oxidation activity of Cu-CeO2 was evaluated by elemental mercury oxidation in the flue gas. Specifically, the Cu-CeO2 nanorings had a superior mercury oxidation efficiency of about 100% at 200 ℃ due to the abundance of oxygen vacancies.

Sonochemical oxidation and stabilization of liquid elemental mercury in water and soil

Over 3000 mercury (Hg)-contaminated sites worldwide contain liquid metallic Hg [Hg(0)l] representing a continuous source of elemental Hg(0) in the environment through volatilization and solubilization in water. Currently, there are few effective treatment technologies available to remove or sequester Hg(0)l in situ. We investigated sonochemical treatments coupled with complexing agents, polysulfide and sulfide, in oxidizing Hg(0)l and stabilizing Hg in water, soil and quartz sand. Results indicate that sonication is highly effective in breaking up and oxidizing liquid Hg(0)l beads via acoustic cavitation, particularly in the presence of polysulfide. Without complexing agents, sonication caused only minor oxidation of Hg(0)l but increased headspace gaseous Hg(0)g and dissolved Hg(0)aq in water. However, the presence of polysulfide essentially stopped Hg(0) volatilization and solubilization. As a charged polymer, polysulfide was more effective than sulfide in oxidizing Hg(0)l and subsequently stabilizing the precipitated metacinnabar (β-HgS) nanocrystals. Sonochemical treatments with sulfide yielded incomplete oxidation of Hg(0)l, likely resulting from the formation of HgS coatings on the dispersed µm-size Hg(0)l bead surfaces. Sonication with polysulfide also resulted in rapid oxidation of Hg(0)l and precipitation of HgS in quartz sand and in the Hg(0)l-contaminated soil. This research indicates that sonochemical treatment with polysulfide could be an effective means in rapidly converting Hg(0)l to insoluble HgS precipitates in water and sediments, thereby preventing its further emission and release to the environment. We suggest that future studies are performed to confirm its technical feasibility and treatment efficacy for remediation applications.

Comprehensive Occupational and Environmental Risk Assessment of Elemental Mercury at the Edison National Historic Site in West Orange, NJ

The Thomas A. Edison National Laboratory in West Orange, NJ was used to research and develop many inventions including experiments with a mercury oxide battery. Historical letter from Ms. Kellogg to Thomas Edison in 1884 reported the outcome of using mercury while conducting research. Preliminary test results showed spread of some contamination to artifact throughout the laboratory but the majority of the mercury was confined to a specific area of the lab. Spillage of elemental mercury in the Small Dry Cell Lab on the third floor of Building 5 leaked through the floor and ceiling on the second floor below. A comprehensive preliminary site risk assessment was conducted to evaluate the location and extent of the mercury contamination. Remediation work was conducted to remove the wood floor and ceiling but the work plan and health and safety plan for the project was inadequate. Workers were exposed to elevated levels of mercury vapor. Changes were made to reduce the risk and occupational exposure. The work was accomplished successfully without mercury poisioning after implementing more elaborate engineering and administrative controls.

Role of CuFe2O4 in elemental mercury adsorption and oxidation on modified bentonite for coal gasification

• Roles of CuFe 2 O 4 in Hg 0 adsorption and oxidation on CuFe 2 O 4 -modified bentonite. • Hg 0 adsorption and oxidation mechanism of CuFe 2 O 4 established. • The adsorption of Hg 0 on the surface of CuFe 2 O 4 (1 1 0) have the stronger interaction. Taking spinel CuFe 2 O 4 -modified bentonite as the research object, the experimental and thermodynamic techniques were integrated to study the effect of CuFe 2 O 4 active components on removing Hg 0 in coal gasification process. Meanwhile, the density functional theory was adopted to identify the CuFe 2 O 4 ’s adsorption and oxidation mechanisms for Hg 0 . The results showed that the doping of CuFe 2 O 4 increased the active sites for adsorbing Hg 0 on the surface of bentonite and enabled bentonite with effective magnetic properties. Compared with pure bentonite, the CuFe 2 O 4 -modified one was able to convert more Hg 0 into Hg 2+ and particulate mercury[Hg(P)], which exhibited its better capacities of adsorbing and catalyzing Hg 0 . The thermodynamic simulation outcomes further verified that the bentonite adsorbent modified by CuFe 2 O 4 became more conducive to the conversion of Hg 0 to Hg 2+ . Moreover, DFT results also presented that Hg 0 was under stronger adsorption effect at the Cu-top active sites of CuFe 2 O 4 (1 1 0), which was closely related to the hybridization of orbitals between Hg and Cu atoms. The reaction of Hg 0 with O atoms followed the Markov-Mason mechanism, meaning that Hg diffusion at Fe/Cu-top site was the controlling step, HgO desorption at O-top site and hollow was the control step. The reaction of Hg 0 with active S atoms followed the two mechanisms of Eley−Riddel(E−R) and Langmuir−Hinshlwood (L−H). The energy barrier of L-H mechanism was lower than that of E-R mechanism, which was dominant in the reaction process. The excellent performance suggested that the CuFe 2 O 4 -modified bentonite was a promising sorbent for mercury removal in coal gasification.

New frontiers in heterogeneous Hg0 oxidation by O2 over catalytic single-Fe site on boron-vacancy of h-BN: A density functional theory study

The single-atom catalysts (SACs) have shown tremendous potential in heterogeneous catalytic process, because of their high atomic utilization efficiency and controllable characteristic of various active sites. The accurate structure design at atomic scale of SACs brings new opportunities and challenges for the cost-effective Hg0 oxidation and the study in molecularly catalytic mechanism by the oxidant of O2. Herein, a series of single transition metal atom doped (Mn, Fe, Co, Ni, Cu and Zn) on h-BN vacancy (M/V-BN) were well designed and the interaction behaviours were further investigated via Density Functional Theory (DFT) method. The mercury oxidation profiles and mechanism in the existence of O2 had been clarified on the optimized single atom catalytic site. The results show that the six kinds of TM atoms can exist stably on the surface of boron-vacancy (VB-BN) monolayer and have the potential to activate the new two-dimensional material (h-BN) with high surface reactivity. Among them, the most stable configuration Fe/VB-BN exhibited the best affinity to Hg0 with an adsorption energy of -1.697 eV, and the Fe-Hg bond was the shortest of 2.747 Å. The covalent interaction of Fe-Hg bond is demonstrated by the overlaps between Fe d-orbitals and Hg p-orbital. The chemisorption mechanism dominates the adsorption processes of different mercury species (Hg0, HgO, HgCl, HgBr and HgS), with the adsorption energy ranging from -1.2 to -4.2 eV. The Hg0 oxidation over Fe/VB-BN by O2 mainly follows the Eley-Rideal mechanism, and undergoes three key steps, i.e., O2 molecule dissociation, formation of O-Hg-O structure and desorption of oxidized Hg products. O2 was firstly adsorbed on the unsaturated Fe site and strongly activated by the metal center, which contributes to the high Hg0 catalyst oxidation activity. The generation of O-Hg-O structure is the public stage of mercury products desorption. The rate-determining step of Hg0 catalytic oxidation was dependent on Hg2O2 cluster desorption with an energy of 2.91 eV, which was much smaller than the desorption barrier of traditional catalysts. As a whole, the outcomes demonstrate that Fe/VB-BN catalyst is one promising candidate for catalytic oxidation of Hg0 by O2, which enables cleaner coalfired power plant operations.