Mixture Of NH3 Research Articles

Anti-sintering Ni-ZnO catalyst stabilized by a dual protection of SMSI and carbon for efficient RWGS reaction

Colloidal nanoparticles with uniform particle size distribution, tailored exposed facets, and controllable compositions appealed to broad interests in heterogeneous catalysis. Nevertheless, due to the strong attachment of capping agents to the nanoparticles, cleaning the nanoparticle surface without changing the size of nanoparticles remains a significant challenge. Herein, based on the double confinement of the strong metal-support interaction (SMSI) effect and carbon encapsulation, the well-stabilized Ni-ZnO-S3 catalyst was successfully synthesized. The size of Ni nanoparticles after calcination in the sequence of H2-N2 mixture, air, and H2-N2 mixture remained below 5 nm. Due to no significant size change in Ni nanoparticles, the prepared Ni-ZnO-S3 catalyst served well as model catalysts in the RWGS reaction, where the CO2 conversion and CO yield increased proportionally to the Ni loading weight. According to the result of in-situ FTIR, an associative mechanism of RWGS reaction over Ni-ZnO-S3 was also identified. Therefore, this dual protect strategy provides a potential solution for building highly anti-sintering catalysts based on the colloidal synthesis route.

Synthesis of MgO powders by precipitant for transparent ceramics

In this experiment, MgO powder was prepared through co-precipitation using NH3·H2O and NH4HCO3 as precipitant. The study aimed to investigate the effects of precipitant content and type on the yield of MgO powders. It was found that the highest MgO yield was obtained using a mixture of NH4HCO3 and NH3·H2O as the precipitant. Furthermore, NH3·H2O as the sole precipitant resulted in the smallest particle size. However, an increase in the precipitant content led to a decrease in the specific surface area of the powders and caused powder agglomeration. Subsequently, MgO transparent ceramics were fabricated using a hybrid sintering method involving hot pressing followed by a subsequent hot isostatic pressing treatment. The best microstructure and the highest infrared transmittance of 81% at 5.81 μm were achieved for the MgO transparent ceramic samples hot-pressed at 1500 °C and then subjected to hot isostatic pressing at 1500 °C. The relative density reached 99.97%.

Photocatalysis: A Possible Vital Contributor to the Evolution of the Prebiotic Atmosphere and the Warming of the Early Earth

The evolution of the early atmosphere was driven by changes in its chemical composition, which involved the formation of some critical gases. In this study, we demonstrate that nitrous oxide (N2O) can be produced from Miller’s early atmosphere (a mixture of CH4, NH3, H2, and H2O) by way of photocatalysis. Both NH3 and H2O were indispensable for the production of N2O by photocatalysis. Different conditions related to seawater and reaction temperature are also explored. N2O has a strong greenhouse gas effect, which is more able to warm the Earth than other gases and offers a reasonable explanation for the faint young Sun paradox on the early Earth. Moreover, the decomposition of N2O into N2 and O2 can be boosted by soft irradiation, providing a possible and important origin of atmospheric O2 and N2. The occurrence of O2 propelled the evolution of the atmosphere from being fundamentally reducing to oxidizing. This work describes a possible vital contribution of photocatalysis to the evolution of the early atmosphere.

Effect of nitriding temperature and its effects on the corrosion and wear resistance of 304 austenitic stainless steel

Rapid plasma nitriding of AISI 304 austenitic stainless steel (304SS) was carried out at 440, 460 °C and 480 °C for 1 h in a mixture of NH3 and N2 with a ratio of 1:2. The phase composition, thickness of nitrided layer and properties of wear, and corrosion resistance were evaluated. After nitriding at 480 °C for 1 h, a 6.3 μm the thick nitrided layer was achieved. The influence of the nitriding process on the microstructure, morphology, hardness, corrosion, and wear resistance of the nitrided layers were also studied. Compared with unnitrided 304SS, the wear and corrosion resistances were substantially improved.

MEMS-based electronic nose system for measurement of industrial gases with drift correction methodology

This work explores the use of microelectromechanical system (MEMS) sensors in electronic nose systems for the measurement of prominent industrial pollutants and proposes a methodology for the correction of drift induced in sensors during prolonged use for measurement of corrosive compounds. MEMS sensors have the advantages of low recovery and response time, lower power consumption and improved sensitivity. An electronic nose system is developed to quantify the four major pollutants emitted from various process industries, i.e. hydrogen sulfide (H2S), carbon monoxide (CO), ammonia (NH3) and ethanol (C2H5OH). All four pollutants represent major environmental and human health hazards and rapid quantification is vital. A drift correction algorithm was developed using experimental design and robust regression to correct the drift induced in the sensors. The experiments consisted of eight experimental sets with mixtures of H2S, CO, NH3 and C2H5OH measured on the same sensor array at the start and after a gap of 1 year. The methodology consisted of mapping the response of sensors after 1 year compared with that observed at the very start (day 1) of the experiment. The results showed successful implementation of the methodology, with the root mean square error values being significantly reduced at 0.235, 0.354, 0.145 and 0.651, respectively, for the four studied odorants (H2S, NH3, CO, and C2H5OH).

Ammonia energy storage for hybrid electric aircraft

This work considers the development of a hybrid electric vertical takeoff and landing aircraft with an NH3 engine. An NH3 cracker with an external heat supply from the engine and a high-temperature catalytic reactor is needed to crack part of the NH3 in H2 and N2. The engine has two turbochargers in cascade, an intercooler, and an SCR catalyst with additional NH3 injection before the catalyst to control emissions. The H2 is used to ignite an NH3 mixture which may also be enriched with hydrogen to address particularly slow-burning points. The proposed learn burn engine which features direct injection and jet ignition of H2 may have power densities above 100 kW per liter and fuel conversion efficiencies approaching 50%. This engine can be further specialized to work on a narrow range of speeds and loads, ideally, one single point, to produce electricity on board the aircraft. The energy storage per unit mass of the complete system is expected to reduce vs. diesel but not dramatically. Importantly, it is much better than the storage of energy in a battery.

Ammonia generation in Ns pulse and Ns pulse/RF discharges over a catalytic surface

Plasma-catalytic ammonia synthesis in a ns pulse discharge and a ‘hybrid’ ns pulse/RF discharge in plane-to-plane geometry is studied by Fourier Transform infrared absorption spectroscopy. The data are taken in a preheated H2–N2 mixture, with and without Ni/γ-Al2O3 or Co/γ-Al2O3 catalyst placed in the discharge section. The measurement results are taken using two different approaches. The first is a ‘single-stage’ process, where a ns pulse discharge in the H2–N2 mixture is sustained continuously. In this case, the ammonia yield increases slowly, over a period of tens of minutes. The second is a ‘two-stage’ process, where the catalyst is first activated by the ns pulse discharge sustained in pure nitrogen, and then the activated catalyst is exposed to the H2–N2 flow, with or without the discharge. In this case, a strong overshoot of the NH3 number density at the reactor exit is detected, by over a factor of two compared to the single-stage process. After the initial overshoot, the ammonia yield gradually decreases to the ‘single stage’ value (with the discharge on), or to near zero (with the discharge off). The results demonstrate that the ammonia yield in the plasma-catalytic reactor is controlled by the N atom accumulation on the catalyst surface, which reacts with H atoms thermally dissociated on the catalyst or generated in the plasma. The results also show that the plasma-catalytic ammonia yield is significantly higher compared to that in the ns pulse discharge without the catalyst. The accumulation of H atoms on the catalyst, with their subsequent reactions with N atoms generated in the plasma, is of relatively minor importance at the present conditions. An additional series of measurements was made with a sub-breakdown RF waveform overlapped with the ns pulse discharge train, to enhance the vibrational excitation of nitrogen. The ammonia yield measured with the RF waveform added is approximately 20% higher compared to that at the baseline ns pulse discharge conditions, both with and without the catalyst. This effect is weaker compared to that of the catalyst activation by N atoms. Additional data are necessary to isolate the possible effect of the vibrationally excited N2 molecules on the ammonia synthesis in the plasma catalytic reactions.

Effect of Co-existing gases on hydrogen permeation through a Pd82–Ag18/α-Al2O3 membrane during transient start-up

The work aimed to study the influence of co-existing gaseous mixture (H2–N2–CO–CO2) on hydrogen permeation through the counter-current flow of a Pd82–Ag18/α-Al2O3 membrane during transient start-up at 350 °C and atmospheric pressure. The membrane was operated for an 8-h. Its performance was measured in terms of hydrogen flux and recovery. The results were mapped on Sieverts-Fick's line and showed a slight membrane deactivation because of the presence of N2 and CO2 in the feed gas. The membrane deactivation became more profound when CO was a constituent. The effect of the co-existing gases on the hydrogen flux, in increasing order, was CO > CO2>N2. The co-existing gases, if present as a significant fraction, induces dilution, concentration polarization, and inhibition over the membrane surface, decreases the membrane performance in term of hydrogen recovery, time lag during transient start-up, and deactivation. It is recommended that the start-up might be run using equimolar H2–N2 mixture.

Room-Temperature Ammonia Gas Sensor Based on Ti3C2Tx MXene/Graphene Oxide/CuO/ZnO Nanocomposite

Two-dimensional (2D) Ti3C2Tx Mxene has currently demonstrated significant potential for gas sensing application with a high signal-to-noise ratio at room temperature. Herein, we present the mixture of popular NH3 sensing materials such as graphene oxide (GO), copper oxide (CuO), and zinc oxide (ZnO) into Ti3C2Tx Mxene to be a high-performance NH3 gas sensor at room temperature. Various nanocomposites such as Mxene/GO, Mxene/ZnO, Mxene/CuO, Mxene/GO/ZnO, Mxene/GO/CuO, Mxene/ZnO/CuO, and Mxene/GO/ZnO/CuO were synthesized via the hydrothermal method and used as NH3 sensing materials in room-temperature gas sensors. The Ti3C2Tx MXene/GO/CuO/ZnO nanocomposite gas sensor exhibited the best NH3 gas sensor. The effects on the weight ratios of Ti3C2Tx MXene/GO/CuO/ZnO were also investigated, and the optimal Ti3C2Tx MXene/GO/CuO/ZnO weight ratio was determined to be 9:1:5:5. The optimal Ti3C2Tx MXene/GO/CuO/ZnO based gas sensor showed a high response of 96% at 200 ppm of NH3, humidity independence in the range of 30–70%RH, good linear relationship (R2 = 0.998), low limit of detection of 4.1 ppm, and high selectivity to NH3 over several gases/VOCs including formaldehyde, ethanol, methanol, isopropanol, toluene, and acetone. The NH3-sensing mechanism was proposed based on the modulation of complex p–n heterojunctions via the electron accumulation layer in the n-type of GO/CuO/ZnO and the electron depletion layer in the p-type Ti3C2Tx Mxene.

An investigation for H2/N2 adsorptive separation in SIFSIX-2-Cu-i

Hydrogen recovery from ammonia purge gas is a desirable method to relieve the pressure of increasing demand for hydrogen. Metal-organic frameworks (MOFs) are promising adsorbents for the separation of the H2–N2 mixture. However, the separation of the H2–N2 mixture using MOFs remains challenging due to the lack of adsorptive mechanism. Herein, the adsorption mechanism of the H2–N2 mixture in SIFSIX-2-Cu-i has been systematically investigated with the method of a combination of excess adsorption experiments, molecular simulations, and DFT calculations. In the Grand Canonical Monte Carlo (GCMC) simulations, the polarizable force field was first applied to the adsorption of pure H2 or N2 and H2–N2 mixture in SIFSIX-2-Cu-i. Ab Initio Molecular Dynamics (AIMD) was performed to investigate the distribution of the guest molecules in the pores of SIFSIX-2-Cu-i. Finally, Density functional theory (DFT) calculations were performed to predict the transfer of charge between MOF and guest molecules. Results revealed two binding sites of H2 or N2 in SIFSIX-2-Cu-i. A relatively high thermodynamic adsorption selectivity for N2 over H2 has been observed in SIFSIX-2-Cu-i. Furthermore, SIFSIX-2-Cu-i also exhibits a greater affinity with N2 than with H2, which is probably because of the stronger induction interactions between F2 atoms and N2 molecules. These findings are of significance to guide the design of the new highly selective adsorbents for the separation of H2/N2.

Thermodynamic evaluation of the effects of hydrogen blending on the Joule-Thomson characteristics of hydrogen-blended natural gas

The Joule-Thomson characteristics of hydrogen-blended natural gas (HBNG) differ from those of natural gas for the differences in properties, deserving a profound study. We foremost analyzed the effects of hydrogen on the properties of HBNG using the Soave-Benedict-Webb-Rubin (BWRS) equation of state (EOS) owing to its lowest deviation among the concerned EOSs. Based on BWRS EOS, the fundamental differential equation, and the isenthalpic equation, we developed a thermodynamic model to evaluate the effects of hydrogen on the isenthalpic curve, Joule-Thomson coefficient (JTC), and Joule-Thomson inversion curve (JTIC) of HBNG within the hydrogen mole fraction (x-H2) range of 30%. The average absolute relative deviation (AARD) for the isenthalpic curve of the N2-H2 mixture and the JTC of natural gas is 0.02% and 1.62%. We mainly discussed how hydrogen affects the isenthalpic curve, JTC, and JTIC of HBNG. The isenthalpic curve of the CH4-H2 mixture and HBNG rise in a descending gradient with increasing x-H2. Compared to natural gas, the JTC of HBNG decreases (about 48% when x-H2 is 30%) and negatively correlates to x-H2, pressure, and temperature in a nonlinear function. The JTC is more sensitive to the x-H2 at higher temperatures and lower pressures. The blended hydrogen narrows the positive effect region of HBNG but does not turn the positive effect into a negative one within the x-H2 range of 30%. When x-H2 increases from 0% to 30%, the maximum inversion pressure and corresponding temperature drop at a rate of 0.227 MPa/x-H2% (roughly linear) and 4.9385 K/x-H2% (linear), respectively.

Mixed gas concentration inversion based on the hierarchical feature fusion convolutional neural network

Recently, the detection of gas mixtures has attracted considerable attention due to its promising application in disease diagnosis, environmental monitoring and so on. However, the detection of gas mixtures is inevitably subject to the cross-interference between different components. Herein, we propose a hierarchical feature fusion convolutional neural network (CNN) model for mixed gas concentration inversion. In our experiment, mixtures of SO2, NO2 and NH3 were analyzed. SO2 and NO2 were the detected gases while NH3 was the interfering gas. The proposed model can be applied to low-resolution spectra. Compared with the model without hierarchical structure and feature fusion, the mean absolute errors of SO2 and NO2 decreased by 80.3% and 87.0% in the simulated spectral samples. The experimental results also demonstrate that the proposed model could effectively reduce the cross-interference and improve the accuracy of gas concentration inversion. This model would have a promising application in the field of gas detection and low-resolution spectra.

Enhanced sensitivity towards LPG with selectivity between LPG, NO2, and NH3 by novel CoFe2O4/SiC/BaTiO3 nanocomposites

In this paper, the enhanced sensitivity and selectivity between LPG, NO2, and NH3 by novel CoFe2O4/SiC/BaTiO3 (CFO/SiC/BTO) ternary nanocomposites synthesized by chemical coprecipitation and solid-state methods have been reported. The structural and morphological properties of nanocomposites were analysed using XRD, SEM and EDS respectively. The highest dielectric permittivity ∼665 at 8 kHz for 30 wt% BTO with lowest dielectric loss at high temperature was achieved using LCR meter. Moreover, the maximum response (%) was obtained towards LPG ∼84%, while it was found to be ∼11% for NH3 and ∼23% for NO2 at 220 ppm, whilst it was achieved more than 95% above 150 °C for all the gases. Furthermore, the selectivity ∼95% at room temperature was acquired for LPG in presence of NH3. The excellent response (%) ∼ 99.68% and 99.85% was obtained for mixture of LPG-NO2 and LPG-NH3 at 300 °C for 30 wt% BTO, which was also confirmed by obtained activation energy. Accordingly, 30 wt% BTO of CFO/SiC/BTO nanocomposites is providing excellent sensitivity and selectivity towards LPG in the mixture of NO2 and NH3.

Influence of Anticorrosive Surface Treatment of Steel Reinforcement Fibers on the Properties of Ultra-High Performance Cement Composite.

The influence on the bond between the steel fiber and the matrix of the anticorrosive treatments of steel used for concrete reinforcement is not yet fully understood. The topic of steel fiber treatment was not also studied clearly in terms of brass removal before. This paper deals with how the brass on the surface of steel fibers behaves in the UHPC matrix and how it affects its properties. The steel fibers were firstly modified with a number of surface treatments to remove brass on their surface. Some of the treatments have never been tried before for this purpose. Secondly, the surface of the fibers was analyzed by SEM, EDS, XRF, and stereomicroscopy. Lastly, the properties of the composites were analyzed. It was found out that the majority of brass on the surface of the fibers could be removed by mixture of NH3 and H2O2 with a ratio of 3:1 (v/v). It was also found out that the surface treatment slightly affects the mechanical properties, but it does that only by mechanical interlocking between the fiber and the matrix. No dissolution of the surface treatment was observed under the given conditions. According to the results, steel fibers without surface treatment should be used in UHPC if available.

Experimental and kinetic study on the extinction characteristics of ammonia-dimethyl ether diffusion flame

Combustion with dimethyl ether is regarded as one of the effective means to improve the combustion stability of ammonia gas. In-depth understanding of the combustion characteristics of ammonia-dimethyl ether mixture, especially the extinction limits, is the basis for the development of related combustion technology. In this work, the extinction limits of diffusion flames of NH3, DME and NH3-DME mixture were obtained through experiments, and a kinetic model was developed to accurately describe the combustion characteristics of NH3-DME, especially for the extinction limits. The extinction characteristics of NH3-DME mixture were analyzed based on this model. The experimental results show that blending DME in the fuel or increasing the oxygen concentration in the oxidant can effectively expand the combustion limits of the NH3 diffusion flame. When the oxygen mole fraction in the oxidant is increased to 27%, the strain rate at extinction of the NH3 diffusion flame is 3.3 times of the original value. When NH3 is mixed with 10% volume fraction of DME, the increase is 3.9 times. Numerical analysis shows that the chemical and thermal effects of DME promote the combustion of NH3-DME mixture, and when the DME mole fraction in fuel exceeds 33%, the effect of chemical effect is bound to exceed the thermal effect. With the increase of the strain rate, the reaction zone of the flame becomes thinner, the escape rate of active radicals increase, and the heat release rate of per unit mass of fuel decreases, which leads to the continuous decrease of the flame temperature and eventually leads to flame extinction. The addition of DME increases the thickness of flame, increases the amount of radical generation and improves the heat release rate of the reaction process, thus promoting the combustion and improving the stability of NH3 diffusion flame.

Synthesis and Characterization of Bioactive Magnetic Nanoparticles from the Perspective of Hyperthermia Applications

Magnetic iron oxide nanoparticles were obtained for the first time via the green chemistry approach, starting from two aqueous extracts of wormwood (Artemisia absinthium L.), both leaf and stems. In order to obtain magnetic nanoparticles suitable for medical purposes, more precisely with hyperthermia inducing features, a synthesis reaction was conducted, both at room temperature (25 °C) and at 80 °C, and with two formulations of the precipitation agent. Both the quality and stability of the synthesized magnetic iron oxide nanoparticles were physiochemically characterized: phase composition (X-ray powder diffraction (XRD)), thermal behavior (thermogravimetry (TG) and differential scanning calorimetry (DSC)), electron microscopy (scanning (SEM) and transmission (TEM)), and magnetic properties (DC and HF-AC). The magnetic investigation of the as-obtained magnetic iron oxide nanoparticles revealed that the synthesis at 80 °C using a mixture of NaOH and NH3(aq) increases their diameter and implicitly enhances their specific absorption rate (SAR), a mandatory parameter for practical applications in hyperthermia.

NH3[sbnd]NO interaction at low-temperatures: An experimental and modeling study

The present work provides new insight into NH3NO interaction under low-temperature conditions. The oxidation process of neat NH3 and NH3 doped with NO (450, 800 ppm) was experimentally investigated in a Jet Stirred Flow Reactor at atmospheric pressure for the temperature range 900–1350 K. Results showed NO concentration is entirely controlled by DeNOx reactions in the temperature range 1100–1250 K, while NH3NO interaction does not develop through a sensitizing NO effect, for these operating conditions.A detailed kinetic model was developed by systematically updating rate constants of controlling reactions and declaring new reactions for N2H2 isomers (cis and trans). The proposed mechanism well captures target species as NO and H2 profiles. For NH3NO mixtures, NO profiles were properly reproduced through updated DeNOx chemistry, while NH2 recombination reactions were found to be essential for predicting the formation of H2. The role of ammonia as a third-body species is implemented in the updated mechanism, with remarkable effects on species predictions. For neat NH3 mixture, the reaction H+O2(+M)=HO2(+M) was crucial to predict NO formation via the reaction NH2+HO2H2NO+OH.

Vapor–Liquid Equilibrium Measurements for Aqueous Mixtures of NH3+ MDEA + CO2and KOH + MDEA

Isothermal vapor–liquid equilibrium measurements were performed for aqueous solutions containing N-methyl diethanolamine (MDEA), MDEA + ammonia (NH3), MDEA + potassium hydroxide (KOH), MDEA + carbon dioxide (CO2), NH3 + CO2, and MDEA + NH3 + CO2. The experiments were carried out between 310 and 390 K and 0.07 and 34 bar using a static synthetic apparatus. Overall, 202 data points are reported in terms of total volume, total number of moles, temperature, and pressure. The experimental results for MDEA(aq), NH3(aq) + CO2(aq), and MDEA(aq) + CO2(aq) are in good agreement with the calculations done using the Extended UNIQUAC model within the studied range. The data presented in this work are also comparable to previously published measurements. This work reports for the first time VLE measurements for aqueous mixtures of MDEA + NH3 and MDEA + KOH. These data suggest that the interactions between MDEA(aq) and NH3(aq) or K+(aq) ions have a minor effect on the equilibrium pressures. Consequently, other physical properties are needed to describe the thermodynamic state of these systems, such as heat capacity, heat of dilution, and other phase equilibrium measurements. The isothermal VLE measurements for solutions containing NH3(aq) showed a pressure minimum that was confirmed by model estimates and by other works done in similar conditions. As a consequence, it is not possible to estimate the partial pressure of CO2 based on the difference between the pressure at equilibrium conditions and the partial pressure of the lean solvent. This paper demonstrates that this common approach to determining the partial pressure of gases may introduce a bias in these values. The dissolution of CO2 into MDEA(aq) + NH3(aq) mixtures changes the speciation of the system, leading to an increase in the concentration of their protonated species (MDEAH+(aq) and NH4+(aq), respectively). For this reason, the interaction between these charged species must be determined in order to perform reliable phase equilibrium calculations. Ultimately, the measurements reported in this work can be used for thermodynamic modeling of CO2 capture solvents to ensure accurate results in process simulation.

A new 2D metallic K3Cl2 nanosheet as a promising candidate of NO2 gas sensor and capturer

Based on first-principles computations and global search method, we identify a new two-dimensional K3Cl2 nanosheet with unique structural and electrical properties. Formation energy and phonon spectrum calculations and ab initio molecular dynamics (AIMD) simulations confirm the stability of this predicted structure. The metallic character of the K3Cl2 can be maintained under tensile uniaxial and biaxial strains. The calculation demonstrates that K3Cl2 nanosheet can effectively detect NO2 molecules from the mixture of H2, H2O, NH3, CO, NO, NO2 and CO2. Thereason of the conversion from metal to semiconductor of K3Cl2 adsorbing different number of NO2 molecules mightlie in the change of bonding/antibonding state of K-N, K-O and NO bonds. Our calculated results show that K3Cl2 nanosheet is a promising NO2 gas sensor and capturer with high selectivity and sensitivity.

Loss‐induced phase transition in mid‐infrared plasmonic metamaterials for ultrasensitive vibrational spectroscopy

AbstractMetamaterials have proven their ability to possess extraordinary physical properties distinct from naturally available materials, leading to exciting sensing functionalities and applications. However, metamaterial‐based sensing applications suffer from severe performance limitations due to noise interference and design constraints. Here, we propose a dual‐phase strategy that leverages loss‐induced different Fano‐resonant phases to access both destructive and constructive signals of molecular vibration. When the two reverse signals are innovatively combined, the noise in the detection system is effectively suppressed, thereby breaking through the noise‐related limitations. Additionally, by utilizing loss optimization of the plasmon‐molecule coupling system, our dual‐phase strategy enhances the efficiency of infrared energy transfer into the molecule without any additional fabrication complex, thereby overcoming the trade‐off dilemma between performance and fabrication cost. Thanks to the pioneering breakthroughs in the limitations, our dual‐phase strategy possesses an overwhelming competitive advantage in ultrasensitive vibrational spectroscopy over traditional metamaterial technology, including strong signal strength (×4), high sensitivity (×4.2), effective noise suppression (30%), low detection limit (13 ppm), and excellent selectivity among CO2, NH3, and CH4mixtures. This work not only opens the door to various emerging ultrasensitive detection applications, including ultrasensitive in‐breath diagnostics and high‐information analysis of molecular information in dynamic reactions, but also gains new insights into the plasmon‐molecule interactions in advanced metamaterials.image