Hg Vapor Research Articles

Role of Ceria in the Design of Composite Materials for Elemental Mercury Removal

The necessity to drastically act against mercury pollution has been emphatically addressed by the United Nations. Coal-fired power plants contribute a great deal to the anthropogenic emissions; therefore, numerous sorbents/catalysts have been developed to remove elemental mercury (Hg0 ) from flue gases. Among them, ceria (CeO2 ) has attracted significant interest, due to its reversible Ce3+ /Ce4+ redox pair, surface-bound defects and acid-base properties. The removal efficiency of Hg0 vapor depends among others, on the flue gas composition and temperature. CeO2 can be incorporated into known materials in such a way that the abatement process can be effective at different operating conditions. Hence, the scope of this account is to discuss the role of CeO2 as a promoter, active phase and support in the design of composite Hg0 sorbents/catalysts. The elucidation of each of these roles would allow the integration of CeO2 advantageous characteristics to such degree, that tailor-made environmental solution to complex issues can be provided within a broader application scope. Besides, it would offer invaluable input to theoretical calculations that could enable the materials screening and engineering at a low cost and with high accuracy.

Re-emission of legacy mercury from soil adjacent to closed point sources of Hg emission

Mercury (Hg) emissions from point sources to air may disperse over long distance depending on Hg speciation in the plume. A significant fraction of Hg, particularly in its divalent forms, deposits locally and causes pollution to surrounding biomes. The objective of this study was to investigate (1) the historic Hg deposition to the immediate vicinity of an industrial complex that had intentional use of Hg (i.e., chlor-alkali and polyvinyl chloride production) for 5 decades until 2011, and (2) the Hg0 re-emission from soil to air soon after the closure of the facility. The spatial distribution of near-ground Hg0 vapor in air, soil Hg concentration and stable isotope ratio, air-soil Hg0 flux and Hg0 concentration in soil pore-gas were measured. It was found that the surrounding soils are severely contaminated with Hg due to the Hg release of the industrial complex, displaying soil Hg content up to 4.8 μg g−1. A spatial trend of Hg mass dependent isotope fractionation signature (δ202Hg = −2.11‰ to 0.72‰) with respect to the distance from the closed facility was identified, representing a mixing between regional background and industrial Hg sources. Hg release from the industrial operation enhanced surface soil Hg content within a 6.5-km radius from the facility. Inside the facility, residual Hg wastes (i.e., electrolysis sludge and consumed HgCl2 catalyst) represent a strong localized emission source of atmospheric Hg0. Near-ground atmospheric Hg0 concentration and soil Hg0 efflux progressively elevated toward the facility with an increase by 2–3 orders of magnitude compared to the values observed in the off-site background. These results suggest that the natural soil surfaces surrounding the closed industrial facility act as a large nonpoint source emitting legacy deposited Hg as much as the release from naturally enriched mines.

Investigation and simulation of the transport of gas containing mercury in microporous silica membranes

This work investigates the effect of condensable Hg vapour on the transport of N2 gas across cobalt oxide silica (CoOxSi) membranes. Experimental results suggest that Hg significantly affects N2 permeation at 100 and 200 °C, though this effect is negligible at 300 °C. This effect was found to have a correlation with Hg adsorption on CoOxSi xerogels. In order to understand the Hg effect in the transport phenomena of N2 permeation, the oscillator model was used to model gas transport through pores with different sizes. By including effective medium theory (EMT), the oscillator model fitted well the experimental results and gave good prediction of mass transfer in ultra-microporous materials with a tri-modal pore size distribution, such as silica membranes. It is postulated that Hg seeks lower level potentials in micro-pores, and therefore Hg molecules tend to block small pores (2.5–4 Å from 2.9 Å), or reduce the average pore size of larger pores (6.7–7.8 Å and 12–14 Å). Although N2 permeation decreased with the presence of Hg, it did not decrease when the Hg load was increased by a factor of ten; this strongly suggests the adsorption of Hg molecules in the smaller pores (2.5–4.0 Å), or along the pore wall for the larger pore ranges (6.7–7.8 Å and 12–14 Å).

Reversible chemiresistive sensing of ultra-low levels of elemental mercury vapor using thermally reduced graphene oxide.

A chemiresistor sensor for ultra-low levels of elemental mercury (Hg0) vapor is described. The sensor was prepared through thermal reduction of graphene oxide (GO) deposited on an interdigitated electrode using only low temperature annealing typically at 230°C. The sensor responds to the presence of Hg0 vapor within <1min and spontaneously recovers its baseline through flushing with a Hg0-free carrier gas. The sensor has a linear response in the range of 0.5 to 12.2 ppbv ofHg0 vapor and a detection limit of 0.10 ppbv. The amount of GO and annealing temperature affect the sensor response and were optimized. The sensor can find use in monitoring exposure of persons to Hg0 vapors, for which a threshold value of 6.1 ppbv has been set by the World Health Organization. Graphical abstract Schematic of an interdigitated electrode modified with a layer ofthermally reduced graphene oxide. It can be used as a chemiresistive sensor for Hg0 vapor. The sensor displays a rapid and reversible response and has an ultralow detection limit of 0.10 ppbv.

Removal of PCDD/Fs, PCP and mercury from sediments: Thermal oxidation versus pyrolysis

A continuous pilot-scale system (CPS) equipped with effective air pollution control devices (APCDs) is used for remediating the sediments contaminated with PCDD/Fs, PCP and Hg simultaneously. The removal efficiencies of these three pollutants in sediments collected from seawater pond and river, respectively, are evaluated via thermal treatment processes. PAHs and CBz formed during thermal oxidation and pyrolysis are also analyzed for better understanding the behaviors of chlorinated organic compounds. Experimental results indicate that low-molecular-weight PAHs are closely related to the formation of CBz, PCDD/Fs, and CPs, while low chlorinated PCDD/Fs and CBz are predominant in flue gas with thermal oxidation. However, the PM concentration is higher in thermal oxidation than pyrolysis due to the higher air flow rate of thermal oxidation. It may bring more particles out of the furnace and have a greater potential to form PCDD/Fs within APCDs. Besides, the high air flow also dilutes the Hg vapor in flue gas and would require more energy to condense and collect Hg with the quench tower. Furthermore, for removal of total amount of PCDD/Fs, pyrolysis is better than thermal oxidation. Thus, pyrolysis is more suitable for remediating the contaminated sediment. The removal efficiencies of PCDD/Fs, PCP and Hg in sediments achieved with pyrolysis increase with increasing operating temperature and retention time in CPS. Overall, the residual concentrations of PCDD/Fs and PCP in river sediment are higher than that in seawater-pond sediment since significant formation of tar is observed due to higher organic matter content in river sediment.

Development of a High-Resolution Laser Absorption Spectroscopy Method with Application to the Determination of Absolute Concentration of Gaseous Elemental Mercury in Air.

Isotope dilution-cold-vapor-inductively coupled plasma mass spectrometry (ID-CV-ICPMS) has become the primary standard for measurement of gaseous elemental mercury (GEM) mass concentration. However, quantitative mass spectrometry is challenging for several reasons including (1) the need for isotopic spiking with a standard reference material, (2) the requirement for bias-free passive sampling protocols, (3) the need for stable mass spectrometry interface design, and (4) the time and cost involved for gas sampling, sample processing, and instrument calibration. Here, we introduce a high-resolution laser absorption spectroscopy method that eliminates the need for sample-specific calibration standards or detailed analysis of sample treatment losses. This technique involves a tunable, single-frequency laser absorption spectrometer that measures isotopically resolved spectra of elemental mercury (Hg) spectra of 6 1S0 ← 6 3P1 intercombination transition near λ = 253.7 nm. Measured spectra are accurately modeled from first-principles using the Beer-Lambert law and Voigt line profiles combined with literature values for line positions, line shape parameters, and the spontaneous emission Einstein coefficient to obtain GEM mass concentration values. We present application of this method for the measurement of the equilibrium concentration of mercury vapor near room temperature. Three closed systems are considered: two-phase mixtures of liquid Hg and its vapor and binary two-phase mixtures of Hg-air and Hg-N2 near atmospheric pressure. Within the experimental relative standard uncertainty, 0.9-1.5% congruent values of the equilibrium Hg vapor concentration are obtained for the Hg-only, Hg-air, Hg-N2 systems, in confirmation with thermodynamic predictions. We also discuss detection limits and the potential of the present technique to serve as an absolute primary standard for measurements of gas-phase mercury concentration and isotopic composition.

Active methods of mercury removal from flue gases

Due to its adverse impact on health, as well as its global distribution, long atmospheric lifetime and propensity for deposition in the aquatic environment and in living tissue, the US Environmental Protection Agency (US EPA) has classified mercury and its compounds as a severe air quality threat. Such widespread presence of mercury in the environment originates from both natural and anthropogenic sources. Global anthropogenic emission of mercury is evaluated at 2000 Mg year−1. According to the National Centre for Emissions Management (Pol. KOBiZE) report for 2014, Polish annual mercury emissions amount to approximately 10 Mg. Over 90% of mercury emissions in Poland originate from combustion of coal.The purpose of this paper was to understand mercury behaviour during sub-bituminous coal and lignite combustion for flue gas purification in terms of reduction of emissions by active methods. The average mercury content in Polish sub-bituminous coal and lignite was 103.7 and 443.5 μg kg−1. The concentration of mercury in flue gases emitted into the atmosphere was 5.3 μg m−3 for sub-bituminous coal and 17.5 μg m−3 for lignite. The study analysed six low-cost sorbents with the average achieved efficiency of mercury removal from 30.6 to 92.9% for sub-bituminous coal and 22.8 to 80.3% for lignite combustion. Also, the effect of coke dust grain size was examined for mercury sorptive properties. The fine fraction of coke dust (CD) adsorbed within 243–277 μg Hg kg−1, while the largest fraction at only 95 μg Hg kg−1. The CD fraction < 0.063 mm removed almost 92% of mercury during coal combustion, so the concentration of mercury in flue gas decreased from 5.3 to 0.4 μg Hg m−3. The same fraction of CD had removed 93% of mercury from lignite flue gas by reducing the concentration of mercury in the flow from 17.6 to 1.2 μg Hg m−3. The publication also presents the impact of photochemical oxidation of mercury on the effectiveness of Hg vapour removal during combustion of lignite. After physical oxidation of Hg in the flue gas, its effectiveness has increased twofold.

Reaction kinetic study of elemental mercury vapor oxidation with CuCl2

In this study, the reaction kinetics for a heterogeneous oxidation reaction of elemental mercury (Hg(0)) vapor with CuCl2 was studied in a fixed-bed reactor using 2%(wt) CuCl2/α-Al2O3 between 100 and 180 °C for Hg(0) oxidation after air preheater at a typical coal-fired power plant. The reaction rate expression was first order with respect to Hg(0). However, between 100 and 180 °C, CuCl2 over α-Al2O3 agglomerates and sinters. This sintering effect added significant mass-transfer resistance to the diffusion of Hg(0) vapor, and thus made the conversion of CuCl2 incomplete. Therefore, a grain model was formulated to determine the rate constant by taking into account the mass-transfer resistance. The model constituted a two parameter estimation problem for the determination of the rate constant and product layer diffusivity. The model predictions with the two optimum parameters were in good agreement with the experimental data. The activation energy value determined from the rate constant values was significantly lower than those for other Hg(0) oxidation catalysts under HCl and O2 gases reported in the literature. This result corroborates that CuCl2 can enhance Hg(0) oxidation by lowering the activation energy barrier with the reduction of Cu(2+) to Cu(1+) and supplying thermally stable surface Cl sites following a Mars-Maessen mechanism. CuCl2-based catalyst has potential to be applied after air preheater for Hg(0) oxidation followed by the separation of Hg(2+) in wet flue gas desulfurization (FGD) system or by activated carbon (AC) injection.

Reactive gaseous mercury is generated from chloralkali factories resulting in extreme concentrations of mercury in hair of workers

Occupational exposure of chloralkali workers to highly concentrated mercury (Hg) vapour has been linked to an increased risk of renal dysfunction and behavioural changes. It is generally believed that these workers are exposed to elemental Hg, which is used in abundance during the production process however, the lack in analytical techniques that would allow for identification of gaseous Hg species poses a challenge, which needs to be addressed in order to reach a consensus. Here, we present the results from simulated exposure studies, which provide sound evidence of higher adsorption rate of HgCl2 than Hg0 and its irreversible bonding on the surface of hair. We found that chloralkali workers were exposed to HgCl2, which accumulated in extremely high concentrations on the hair surface, more than 1,000 times higher than expected from unexposed subjects and was positively correlated with Hg levels in the finger- and toenails.

Determination of Anisotropic Ion Velocity Distribution Function in Intrinsic Gas Plasma. Theory.

The first seven coefficients of the expansion of the energy and angular distribution functions in Legendre polynomials for Hg+ ions in Hg vapor plasma with the parameter E/P ≈ 400 V/(cm Torr) are measured for the first time using a planar one-sided probe. The analytic solution to the Boltzmann kinetic equation for ions in the plasma of their parent gas is obtained in the conditions when the resonant charge exchange is the predominant process, and ions acquire on their mean free path a velocity much higher than the characteristic velocity of thermal motion of atoms. The presence of an ambipolar field of an arbitrary strength is taken into account. It is shown that the ion velocity distribution function is determined by two parameters and differs substantially from the Maxwellian distribution. Comparison of the results of calculation of the drift velocity of He+ ions in He, Ar+ in Ar, and Hg+ in Hg with the available experimental data shows their conformity. The results of the calculation of the ion distribution function correctly describe the experimental data obtained from its measurement. Analysis of the result shows that in spite of the presence of the strong field, the ion velocity distribution functions are isotropic for ion velocities lower than the average thermal velocity of atoms. With increasing ion velocity, the distribution becomes more and more extended in the direction of the electric field.

Miniaturized dielectric barrier discharge–atomic emission spectrometer for pesticide: Sensitive determination of thiram after derivatization with mercurial ion

A novel method was developed to sensitively determine thiram (which we selected as a representative large molecular organic pesticide) using miniaturized dielectric barrier discharge-atomic emission spectrometry (DBD-AES), based on the determination of free mercurial ion (Hg2+) from Hg labeled thiram complex. The disulfide bond (SS) in thiram was reduced to sulfhydryl (SH) using tris(2-carboxyethyl)phosphine (TCEP), and inorganic Hg2+ was used as the derivatization reagent. It was found that SnCl2 could selectively reduce only free Hg2+ to Hg0 vapor in the presence of Hg2+-labeled thiram complex, which could be separated from sample matrices for sensitive DBD-AES detection. Under the optimized conditions, this method provided high sensitivity for thiram determination, with limits of detection as low as 0.0003mgkg−1 and linear dynamic ranges of 0.001–0.01mgkg−1. This analytical method performs better than the traditional analytical methods, demonstrating the potential usefulness and versatility of this new Hg-labeled DBD-AES system.

Mercury exposure and the toxicity among dental workers: A systematic review

Mercury (Hg), which is the major component of dental amalgam, has the ability to evaporate, enters human system through inhalation and causes serious toxicity among dental workers. Although amalgam containing Hg had been banned completely in several countries, it is still widely used and considered safe in low economical countries due to absence of other cost-effective alternative. In this systematic review, 26 research articles were selected in line with the scope of study through keyword screening. The findings revealed that dental workers associated with filling, restoration or removal of amalgam tasks are in greater risk for many complications, especially reduced neuropsychological function. This is caused by increased Hg vapour level in the ambient air of dental clinics, from the amalgam, and ultimately inhaled by the personnel. This review also outlined factors that determine the severity of Hg toxicity such as gender, servicing period, facilities occupied at clinics and training provided.

Improved methods for signal processing in measurements of mercury by Tekran&amp;lt;sup&amp;gt;®&amp;lt;/sup&amp;gt; 2537A and 2537B instruments

Abstract. Atmospheric Hg measurements are commonly carried out using Tekran® Instruments Corporation's model 2537 Hg vapor analyzers, which employ gold amalgamation preconcentration sampling and detection by thermal desorption (TD) and atomic fluorescence spectrometry (AFS). A generally overlooked and poorly characterized source of analytical uncertainty in those measurements is the method by which the raw Hg atomic fluorescence (AF) signal is processed. Here I describe new software-based methods for processing the raw signal from the Tekran® 2537 instruments, and I evaluate the performances of those methods together with the standard Tekran® internal signal processing method. For test datasets from two Tekran® instruments (one 2537A and one 2537B), I estimate that signal processing uncertainties in Hg loadings determined with the Tekran® method are within ±[1 % + 1.2 pg] and ±[6 % + 0.21 pg], respectively. I demonstrate that the Tekran® method can produce significant low biases (≥ 5 %) not only at low Hg sample loadings (&lt; 5 pg) but also at tropospheric background concentrations of gaseous elemental mercury (GEM) and total mercury (THg) (∼ 1 to 2 ng m−3) under typical operating conditions (sample loadings of 5–10 pg). Signal processing uncertainties associated with the Tekran® method can therefore represent a significant unaccounted for addition to the overall ∼ 10 to 15 % uncertainty previously estimated for Tekran®-based GEM and THg measurements. Signal processing bias can also add significantly to uncertainties in Tekran®-based gaseous oxidized mercury (GOM) and particle-bound mercury (PBM) measurements, which often derive from Hg sample loadings &lt; 5 pg. In comparison, estimated signal processing uncertainties associated with the new methods described herein are low, ranging from within ±0.053 pg, when the Hg thermal desorption peaks are defined manually, to within ±[2 % + 0.080 pg] when peak definition is automated. Mercury limits of detection (LODs) decrease by 31 to 88 % when the new methods are used in place of the Tekran® method. I recommend that signal processing uncertainties be quantified in future applications of the Tekran® 2537 instruments.

Colorimetric determination of mercury vapor using smartphone camera-based imaging

ABSTRACTThe smartphone camera presents a convenient, portable, and low-cost innovation in colorimetric measurements. In this paper, a smartphone camera was applied for the colorimetric detection of gaseous elemental mercury, an atmospheric pollutant of concern in environment, and workplace monitoring. A cuprous iodide (CuI)/polystyrene composite was used as the recognition element, which exhibited a reddish color in the presence of Hg0. Digital images of the sensing reagent phase were captured by a smartphone camera and were analyzed in red–green–blue color space using ImageJ, an open source image processing program. Parameters for the digital colorimetric sensing including the color values, polymer reagent binder, amount of CuI, exposure time, and Hg0 concentration were investigated and optimized. The linear working range of the sensor was from 61 to 270 μg/m3 Hg0 with a correlation coefficient of 0.978. The limit of detection is 16 μg/m3 Hg0. This method shows the feasibility of applying a smartphone camera for a simple, reliable, and inexpensive colorimetric measurement of Hg0 vapor in a gas mixture such as air.

Mercury speciation by differential photochemical vapor generation at UV-B vs. UV-C wavelength

Photochemical vapor generation (PVG) is an effective sample introduction scheme for volatile mercury (Hg). Speciation of Hg++ and MeHg+ was fulfilled for the first time by differential PVG under UV-B vs. UV-C wavelength and applied to fish oil supplements. After liquid-liquid extraction, the aqueous extract was mixed with 0.4% anthranilic acid (AA)-20% formic acid (FA) in a quartz coil, and exposed sequentially to 311nm or 254nm UV light. The resulting Hg0 vapor was detected by atomic fluorescence spectrometry (AFS). At each wavelength, the AFS intensity was a linear function of Hg++ and MeHg+ concentrations, which were solvable from a set of two equations. This method achieved ultrahigh sensitivity with 0.50 and 0.63ngmL−1 limits of detection for Hg++ and MeHg+, respectively, and 73% recovery for MeHg+ at 10ngmL−1. Validation was performed by ICP-MS on total Hg. Obviation of chemical or chromatographic separation rendered this method rapid, green, and cost-effective.

Speciation of trace mercury impurities in fish oil supplements

Fish oil supplement is becoming increasingly popular worldwide because of beneficial long-chain omega-3 polyunsaturated fatty acids. However, mercury (Hg) impurity causes considerable concern because of its toxicity and bioaccumulation in the food chain. In this work, Hg impurities were extracted from fish oil by liquid-liquid partitioning. The sample solution was then mixed with a reductant (0.4% anthranilic acid-20% formic acid) and sequentially exposed to 311 and 254 nm UV radiation. The resulting Hg0 vapor was detected by atomic fluorescence spectrometry. Speciation was fulfilled by solving a set of two linear equations. Recovery of MeHg+ was 73%; total Hg was validated by ICP-MS. This method achieved 0.50 and 0.63 ng mL−1 limits of detection for Hg++ and MeHg+, respectively. Average Hg++ and MeHg+ contents in fish oil samples (n = 38), 0.67 ± 0.45 and 1.1 ± 1.3 ng mL−1, respectively, were 2-3 orders of magnitude lower than those in fish.

Effect of scanning velocity on femtosecond laser-induced periodic surface structures on HgCdTe crystal

In this paper, a femtosecond laser line-scanning irradiation was used to induce the periodic surface microstructure on HgCdTe crystal. Low spatial frequency laser induced periodic surface structures of 650–770nm and high spatial frequency laser induced periodic surface structures of 152–246nm were respectively found with different scanning speeds. The evolution process from low spatial frequency laser induced periodic surface structures to high spatial frequency laser induced periodic surface structures is characterized by scanning electron microscope. Their spatial periods deduced by using a two-dimensional Fourier transformation partly agree with the predictions of the Sipe-Drude theory. Confocal micro-Raman spectral show that the atomic arrangement of induced low spatial frequency laser-induced structures are basically consistent with the crystal in the central area of laser-scanning line, however a new peak at 164cm−1 for the CdTe-like mode becomes evident due to the Hg vaporization when strong laser ablation happens. The obtained surface periodic ripples may have applications in fabricating advanced infrared detector.

Observing Nightlights from Space with TEMPO

The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is a NASA Earth Venture Instrument set to fly in the 2018-2021 timeframe and cover North America from a geostationary orbit. TEMPO is a powerful spectrometer sampling UV and visible wavelengths in two channels (290-490 nm and 540-740 nm) in 0.2 nm steps. This spectroscopic capability will enable TEMPO to characterize many types of artificial lighting at night in addition to its regular daytime air quality and atmospheric chemistry mission. This paper describes the TEMPO instrument and our planned approach to make nighttime observations. A spectral retrieval algorithm will estimate the contributions from sources in a spectral library to map out the usage of various types of lighting (e.g., Hg vapor, high and low pressure Na vapor, LED, fluorescent, and incandescent) over North America. We calculate the sensitivities of such nightlight retrievals using the measured properties of our flight detectors and optics, and conclude that TEMPO will complement well the VIIRS Day-Night Band for the study of artificial lighting at night from space by offering a new and powerful capability to discriminate between lighting types.

Indoor and outdoor levels, sources, and health risk assessment of mercury in dusts from a coal-industry city of China

ABSTRACTTo understand the mercury (Hg) pollution characteristics and health risks in indoor and outdoor dust of Huainan residential areas, 122 dust samples were collected indoors and outdoors. Average Hg contents in indoor and outdoor dusts of Huainan city were 0.321 ± 0.724 (n = 61) and 0.072 ± 0.163 (n = 61) mg/kg respectively. The average Hg content in indoor dust was characterized by PJ (Panji district) > XJJ (Xiejiaji district) > DT (Datong district) > TJA (Tianjiaan district), and in the order of PJ > DT > XJJ >TJA in outdoor dust. According to enrichment factor and geo-accumulation index, the enrichment degree and pollution intensity for Hg are ranked as “very high enrichment” and “heavily polluted” in indoor dust, and “significant enrichment” and “moderately polluted” in outdoor dust Hg concentrations in indoor dust were highly significantly associated with the coal combustion and frequency of open windows, and Hg concentrations in outdoor dust were significantly associated with the coal combustion and traffic density. The inhalation of Hg vapor is the main route of Hg exposure to adult and children. The hazard risks of Hg for different exposure ways in indoor and outdoor dust were more risk for children than for adults, but have no obvious health risk for them.

Galvanic replacement of colloidal monolayer crystal on a QCM device for selective detection of mercury vapor

Bimetallic nanostructures formed through galvanic replacement (GR) reaction have extraordinary activity in various applications such as catalysis, optics, electronics and bio/chemical sensing, just to name a few. However, the homogenous decoration of metal nanoparticles on less noble metal thin-film substrates to produce long range ordered surfaces for sensing applications using this simple, one step reaction has proved to be a challenge. Here, we demonstrate the formation of polystyrene-based (PS-based) monodispersed nanosphere monolayer (PS-MNM), homogeneously decorated with bi-metallic Pd–Au nanostructures through GR reaction. Furthermore, the size of the Au nanoparticles decorated on the Pd-MNM colloids was controlled for gas sensing applications during GR reaction. Upon transferring the developed materials onto a sensor transducer, namely the quartz crystal microbalance (QCM), it was found that the 1mM Au GR solution produced the best performing sensitive layer for elemental mercury (Hg0) vapor sensing application. The sensor had more than 26 times higher response magnitude at 30°C as well as enhanced sensitivity and selectivity over the control Pd-MNM counterpart at 75°C. The homogeneous decoration concept developed here can be transferred to other bimetallic systems.