Adsorption Of Nitrogen Oxides Research Articles

Achieving High Dispersion of Pd in Small-Pore Zeolite SSZ-13: A High-Efficiency Low-Temperature NOx Adsorber.

Passive NO x adsorber (PNA) materials are primarily considered for reducing nitrogen oxide emissions during the low-temperature cold start of a motor vehicle. Pd/SSZ-13 has attracted considerable attention because of its outstanding hydrothermal stability and sulfur resistance. Optimizing the dispersion of precious metal Pd in Pd/SSZ-13 is crucial for enhancing PNA performance and nitrogen oxide adsorption capability. In this study, we prepared Pd/SSZ-13 using different methods and evaluated their influence on the NO x adsorption capability. The characterization results show that the dispersion of precious metal Pd in the Pd/SSZ-13 catalyst prepared by the quantitative ion-exchange method is as high as 92.13%, and the loading amount is as high as 98.93%. Pd predominantly exists as Pd2+, achieving near-total loading and further improving the catalyst's NO x adsorption capacity. This study offers innovative approaches and methods for applying Pd/SSZ-13 as a PNA material, serving as a reference for its further optimization and performance enhancement. Continued research into the preparation and adsorption performance of Pd/SSZ-13 materials could offer solutions to reduce motor vehicle nitrogen oxide emissions.

Dielectric Properties of Materials Used for Microwave-Based NOx Gas Dosimeters.

Nitrogen oxides (NOx), primarily generated from combustion processes, pose significant health and environmental risks. To improve the coordination of measures against excessive NOx emissions, it is necessary to effectively monitor ambient NOx concentrations, which requires the development of precise and cost-efficient detection methods. This study focuses on developing a microwave- or radio frequency (RF)-based gas dosimeter for NOx detection and addresses the optimization of the dosimeter design by examining the dielectric properties of LTCC-based (Low-Temperature Co-fired Ceramics) sensor substrates and barium-based NOx storage materials. The measurements taken utilizing the Microwave Cavity Perturbation (MCP) method revealed that these materials exhibit more pronounced changes in dielectric losses when storing NOx at elevated temperatures. Consequently, operating such a dosimeter at high temperatures (above 300 °C) is recommended to maximize the sensor signal. To evaluate their high-temperature applicability, LTCC substrates were analyzed by measuring their dielectric losses at temperatures up to 600 °C. In terms of NOx storage materials, coating barium on high-surface-area alumina resolved issues related to limited NOx adsorption in pure barium carbonate powders. Additionally, the adsorption of both NO and NO2 was enabled by the application of a platinum catalyst. The change in dielectric losses, which provides the main signal for an RF-based gas dosimeter, only depends on the stored amount of NOx and not on the specific type of nitrogen oxide. Although the change in dielectric losses increases with the temperature, the maximum storage capacity of the material decreases significantly. In addition, at temperatures above 350 °C, NOx is mostly weakly bound, so it will desorb in the absence of NOx. Therefore, in the future development of a reliable RF-based NOx dosimeter, the trade-off between the sensor signal strength and adsorption behavior must be addressed.

Mechanism of heterogeneous reduction of NO over graphite-supported single-atom Fe catalyst: DFT study

The mechanism of nitrogen oxide (NO) reduction over graphite carbon-supported single-atom iron (Fe) catalyst (Fe/G) was investigated by density functional theory (DFT) and transition state theory (TST). The catalyst deactivation was also analyzed. The results revealed that the NO reduction, based on the Eley-Rideal (E-R) mechanism, underwent four stages including N2O formation and release as well as N2 formation and release. However, the NO reduction only involved two stages according to Langmuir-Hinshelwood (L-H) mechanism: N2 formation and release. Furthermore, for the E-R mechanism, the rate-controlling step was NO reduction, where a NO molecule was adsorbed on an Fe atom with an N, O-down structure with energy barrier of 15.5 kJ/mol, lower than that of other paths. Energy barrier analysis indicated that the energy barrier for the reduction of reactive oxygen species was higher than that for the formation of N2. Reactive oxygen species remaining on the surface of Fe atoms after NO decomposition inhibited the adsorption and reduction of NO, leading to catalyst deactivation due to the absence of active sites. The single-atom Fe species promoted the NO reduction. Kinetic analysis results suggested that, upon increasing the reaction temperature, the NO reduction rate increased more significantly than the reactive oxygen transfer rate.

Lean NOx trap catalyst formulation for selective ammonia synthesis from captured NOx

In the Lean NOx Trap (LNT) technology, ammonia (NH3) occurs as reaction intermediate in conversion of trapped nitrogen oxides (NOx) to nitrogen gas (N2) using hydrogen gas (H2) reductant. The use of an LNT for synthesizing NH3 from NOx is potentially an attractive option for small-scale green NH3 production by converting locally produced NOx pollutant to an important chemical. In this work, it is investigated to what extent the product selectivity towards NH3 on the standard model catalyst Pt/BaO/Al2O3 can be maximized depending on reaction conditions for trapping and reducing NOx with H2 in the temperature range of 75–200 °C. The LNT catalyst preparation was varied by using Pt, Pd and bimetallic combinations, as well as different support materials, namely Al2O3, TiO2, ZrO2 and MgO. NOx adsorption and selectivity of captured NOx reduction to ammonia is discussed in terms of texture and the chemical nature of the support. The NH3 selectivity is influenced by the water vapor content in the gas feed. Storage of NOx in absence of water followed by reduction with hydrogen gas in presence of water vapor was found to be the most favorable operation mode of the LNT for NH3 formation. The NH3 selectivity reached 82% at 150 °C. Explanations for the role of water and in this catalytic chemistry are offered and its consequences for catalyst preparation are discussed. The optimum water content of the reacting gases is predicted to be strongly dependent on catalyst preparation.

Mechanistic insights into the adsorption and dissociation of nitrogen oxides on nickel phosphide (Ni2P) catalysts

The escalating concern regarding nitrogen oxides (NOx) emissions, linked to environmental challenges like smog, acid rain, ozone depletion, and global warming, necessitates effective strategies for their mitigation. DeNOx processes, including selective catalytic reduction (SCR), offer potential solutions, but costly precious metal catalysts hinder a widespread implementation. Alternatively, earth-abundant element compounds, particularly transition metal phosphides (TMPs), such as nickel phosphides (Ni2P), have garnered interest due to their promising catalytic performance. This study employed first-principles density functional theory (DFT) methods to investigate the catalytic properties of the (0001) Ni2P surface concerning NOx adsorption and dissociation. Both NO and NO2 are found to exhibit strong reactivity towards Ni2P-(0001)’s surface at the hollow triple-Ni sites, forming stable conjugated structures. Bader charge analysis indicates significant charge transfers during NOx adsorption from the interacting surface to the NOx, resulting in elongated N–O bond lengths, confirmed by vibrational frequency analyses. The dissociation process of NO2 was found to be both thermodynamically and kinetically favorable, with more heat being released than the subsequent NO dissociation’s activation barrier, resulting in a self-sustaining overall reaction. These insights provide valuable knowledge for designing efficient and sustainable Ni2P-based catalytic systems to address NOx emissions in environmental and industrial applications.

Adsorption of NOx by graphene oxide loaded with CeO2 as a catalyst for atmospheric pollution control

In this study, we utilized graphene oxide (GO) loaded with cerium oxide (CeO2) to synthesize GO-CeO2 catalysts using a hydrothermal method and high-temperature calcination. The performance of the catalyst was evaluated by characterization of the catalyst material and testing for nitrogen oxide (NOx) conversion rates and nitrogen gas adsorption isotherm in mixed flue gas. The results demonstrated that increasing the ratio of NO2 in the NO+NO2 mixture significantly enhanced the conversion rate of NOx. Notably, when the proportion of NO2 reached 0.4, the denitrified gas displayed a remarkable increase in NOx conversion rate, exceeding 98%. This finding highlighted that even low concentrations of NO2 can accelerate denitrification reactions. Moreover, increasing the oxygen concentration in the gas exhibited considerable potential to elevate the NOx conversion rate. The oxygen concentration played a vital role in the process of denitrification, and the GO-CeO2 catalyst exhibited a high oxygen storage capacity. Moreover, the GO-CeO2 catalyst maintained a high denitrification efficiency even under high-temperature conditions and demonstrated excellent NOx conversion performance. The catalyst also demonstrated good stability and strong water resistance under varying proportions and temperatures while maintaining a consistent denitrification efficiency. These findings indicated the significant adsorption effect of the graphene oxide loaded with CeO2 catalyst on NOx, suggesting promising potential for application and widespread use.

DFT simulation of structure stability and nitrogen oxide adsorption for nitrogen and oxygen co-modified carbon nanotubes

Nitrogen (N) and oxygen (O) co-modified carbon nanotubes (ONCNTs) have demonstrated potential applications in adsorption and catalysis processes, because the oxygen-containing groups and N-doping atoms can provide abundant surface binding sites. However, their structural stabilities and adsorption interactions under different co-modified levels remain to be explored. Herein, for the first time, the density functional theory approach was applied to quantitatively characterize the structural morphologies and thermodynamic stabilities for a series of ONCNTs. Our findings indicate that co-modification levels can significantly affect their structures and stabilities. An increase in the N-doping concentration largely decreases the thermodynamic stability of ONCNTs, whereas the oxygen-containing functional groups can enhance the stability. A suitable co-modification level was proposed, at which the ONCNTs could maintain stable structural morphology. Meanwhile, the interaction energies and electronic mechanisms between the ONCNTs and nitrogen oxides (NO and NO2) were comprehensively investigated. The degree of oxidation is the main factor determining the interaction and the stronger interaction generally occurs at the 20–40 % oxidation degrees, wherein both chemical and physical interactions are exhibited for NO and only physical interaction for NO2. Our simulation results could be important and valuable to the design and application of the modified CNTs.

Investigating the adsorption behavior of NOx molecules on γ-Al2O3(1 0 0)-supported proximal Pt-Ba clusters using density functional theory

The advancement of low to zero carbon fuels for internal combustion engines has made Nitrogen oxides (NOx) emissions a focal point of engine aftertreatment. Lean NOx Trap (LNT) is one of the most promising technologies for reducing NOx emissions in light-duty vehicles. The proximity of barium (Ba) to platinum (Pt) sites plays a significant role in the adsorption, reduction, and desorption of NOx inside LNT. A simultaneous loading of Pt clusters (Pt3) and barium oxide clusters ((BaO)2) on γ-Al2O3(100) was innovatively established in this study, and the effect of oxide carrier - triatomic catalyst clusters - bimolecular alkaline earth metal oxide clusters was considered comprehensively to examine the effect of Pt-Ba proximity on the NOx adsorption behavior. Interesting trends in the adsorption energy and activation of NOx molecules (including NO/NO2 and the strong greenhouse gas N2O) due to differences in the adsorption sites (from Pt sites to Pt-Ba proximity sites and finally to Ba sites) were found, and the essential reasons for such variations were elucidated by an exhaustive electronic structure analysis. The results of this study are an interesting complement to the current mechanism for storage and reduction of NOx.

Band edges positions prediction of the of Ag nanocluster-decorated titania surfaces and their relationship to NO and NO2 interaction from first-principles calculations

Metal nanoclusters deposited on oxides have been widely used in photocatalysis playing an important role in the design of model catalysts with applications in heterogeneous catalysis. In particular, we are interested in the potential activity of these cluster-supported systems for the removal of nitrogen oxides either by possible catalytic reduction and/or by their adsorption. In this work, using first-principles methods, we evaluate the main characteristics of Agn (n = 1–4) nanoclusters isolated and deposited on anatase TiO2(101) and rutile TiO2(110) surfaces. Our results indicate that they are preferably adsorbed on rutile surface. The different formation energy at each surface can be explained using a Bader charge analysis. Particularly for Ag4 the lowest formation energy is obtained for tetrahedral geometry while the isolated Ag4 geometry is planar. Small silver deposits placed superficially on titania surfaces modify its electronic structures and improve the conduction band edges positions for possible NO reduction. Band edges positions with respect to the vacuum potential have been studied. The comparison of the conduction band minimum with the reduction potentials of NO/N2O and N2O/N2 shows that they are higher, being Ag3 on rutile and Ag1, Ag2 and Ag4P on anatase better for NO reduction. To complete the analysis, the calculation of work function, energy gap, ionization energy and electron affinity are relevant since they allow the location of semiconductor band edges at point of zero charge. Finally, the adsorption of nitrogen oxides is studied where the NO2 adsorption is favored over NO.

Adsorption capacity of biocarbons from residue of supercritical extraction of raw plants

Abstract Bioadsorbents prepared by chemical activation (H3PO4) of the residue of supercritical extraction of green tea leaves and marigold flowers were characterized by elemental analysis, Boehm titration, adsorption/desorption isotherm and scanning electron microscopy (SEM). The adsorption performance aimed at the removal of malachite green, nitrogen oxide and hydrogen sulfide was investigated. The impacts of various influential parameters of malachite green adsorption such as: contact time (8 h), initial dye concentration (20–140 mg/L), temperature (25–65 °C) and adsorbent mass (0.015–0.025 g) were investigated. The adsorption kinetic follows pseudo second-order reaction kinetics (R 2 > 0.99). The adsorption process was best described by the Langmuir isotherm and the maximum capacity of the monolayer was from 126.58 mg/g to 333.33 mg/g for the biocarbons obtained. The negative values of Gibbs free energy indicate the spontaneous character of the process. The presence of steam in the stream of the mixture of gases had a positive effect on adsorption of nitrogen oxide and hydrogen sulfide by the bioadsorbents obtained. The most effective adsorbent of malachite green and toxic gas pollutants proved to be the biocarbon obtained from the residues of supercritical extraction of green tea leaves.

Density Functional Study on Adsorption of NH3 and NOx on the γ-Fe2O3 (111) Surface.

γ-Fe2O3 is considered to be a promising catalyst for the selective catalytic reduction (SCR) of nitrogen oxide (NOx). In this study, first-principle calculations based on the density function theory (DFT) were utilized to explore the adsorption mechanism of NH3, NO, and other molecules on γ-Fe2O3, which is identified as a crucial step in the SCR process to eliminate NOx from coal-fired flue gas. The adsorption characteristics of reactants (NH3 and NOx) and products (N2 and H2O) at different active sites of the γ-Fe2O3 (111) surface were investigated. The results show that the NH3 was preferably adsorbed on the octahedral Fe site, with the N atom bonding to the octahedral Fe site. Both octahedral and tetrahedral Fe atoms were likely involved in bonding with the N and O atoms during the NO adsorption. The NO tended to be adsorbed on the tetrahedral Fe site though the combination of the N atom and the Fe site. Meanwhile, the simultaneous bonding of N and O atoms with surface sites made the adsorption more stable than that of single atom bonding. The γ-Fe2O3 (111) surface exhibited a low adsorption energy for N2 and H2O, suggesting that they could be adsorbed onto the surface but were readily desorbed, thus facilitating the SCR reaction. This work is conducive to reveal the reaction mechanism of SCR on γ-Fe2O3 and contributes to the development of low-temperature iron-based SCR catalysts.

Enhancement of NOx adsorption performance on zeolite via a facile modification strategy.

Adsorption is a promising technology for simultaneously capturing nitrogen oxides (NOx) from flue gases and recycling NO2 as a profitable chemical, for which a robust and efficient adsorbent provides the key step for success in practical applications. This work reports the enhancement of NOx adsorption performances with less cost of desorption energy on Cu-ZSM-5 zeolites prepared by a facile and rapid (690s) modification method, the incipient-wetness impregnation coupled with microwave drying (IM). In comparisons to H-ZSM-5, Na-ZSM-5 and conventionally liquid-phase ion-exchanged counterparts under sub-1000ppm NOx feed concentrations and room temperature, the IM sample renders a record NOx adsorption capacity (qt,NOx) of 0.878mmol/g from dry gas stream on zeolites, and an applicable qt,NOx of 0.1mmol/g from wet gas stream with a proper copper loading (2.1wt%). The temperature programmed desorption of NOx on the optimal IM sample saturated with NOx from wet gas stream exhibit primary peak temperature lower than reported Cu-ZSM-5 and significant NO2 proportion (72.6%) in desorbed NOx. Deeper insights into advantageous NOx oxidative adsorption over the properly-loaded Cu-ZSM-5 in terms of diverse adsorbate states and competitiveness towards H2O were gained, showing IM method a promising sorbent improvement strategy for practical use.

Adsorptive purification of NOx by HZSM-5 zeolites: Effects of Si/Al ratio, temperature, humidity, and gas composition

Adsorption is a promising technology for capturing nitrogen oxides (NOx) from humid flue gases, for which as the preferred NOx adsorbent, zeolite with an appropriate silica to alumina (Si/Al) ratio provides the key step for success in practical applications. In this work, the effects of Si/Al ratio, temperature, relative humidity (RH), and feed gas (NOx-H2O(g)–CO2–O2-N2) compositions on NOx sorption behavior on HZSM-5 zeolites were systematically investigated, based on a series of characterizations, fixed-bed adsorption and temperature programmed desorption (TPD) tests. The low-silica HZSM-5(25) showed the best performance (326.6 μmol/g and 39.2 μmol/g at dry and 90%RH) as compared to others with higher Si/Al ratios at each RH, in which the roll-up effect was positively correlated with the Si/Al ratios and humidity. O2 enhanced NOx adsorption and reached an optimal adsorption capacity at the concentration of 14%, while CO2 had little effect on NOx adsorption. The decrease in temperature increased NOx adsorption capacity on HZSM-5(25), benefitting from NO2 physisorption as well as satisfactory NO oxidation within the active adsorbent structure. The facile thermal desorption of NOx and significant NO–NO2 conversion on HZSM-5(25) was exhibited by bimodal TPD peaks at 343–353K and 533–543K respective for NO and NO2, in contrast to those on Silicalite-1. A potential “water-resistant” strategy via the enhancement of NOx adsorption competitiveness was revealed, providing a theoretical guideline for NOx adsorbent screening in industrial applications.

Combined density functional theory calculation and non-equilibrium Green's function approach to predict the sensitivity of nitrogen-containing gases over PtTenS2-n monolayers (n = 0–2)

Two-dimensional (2D) transition-metal dichalcogenide (TMD) monolayers are potential toxic gas sensors for next-generation industrial applications. In this study, we adopted density functional theory (DFT) calculations to investigate the sensing properties of harmful nitrogen-containing gases (NCGs) on Pt-based TMDs (PtTenS2-n monolayers, where n = 0–2). Our results showed that the electronic interactions of ammonia (NH3) on all TMDs and nitrogen oxides (NOx) on PtS2 were weak. However, the electronic interactions were strong between the NOx molecules and PtTe2 or Janus PtTeS monolayers. Moreover, the bandgap was reduced after NOx adsorption on the PtTe2 and Janus PtTeS monolayers; however, the reduced amplitude of NOx on the Janus PtTeS monolayer was more significant than that on the PtTe2 monolayer. By combining Non-Equilibrium Green’s Function (NEGF) calculations, the sensitivities were all found to be poor for the NCGs on PtS2. Nitrogen dioxide (NO2) exhibited higher sensitivity than those exhibited by NH3 and nitric oxide (NO) at 1.0 V on the PtTe2 monolayer; therefore, the selectivity of NO2 was high under this condition. In addition, NO and NO2 possessed high sensitivities at 0.6 and 0.4 V on the Janus PtTeS monolayer, respectively. Consequently, the sensitivity of NOx molecules on the Janus PtTeS monolayer was higher than that on the PtTe2 and PtS2 monolayers at relatively low applied biases. The results of this study indicate that the Janus PtTeS monolayer is a promising NOx gas sensor with both high selectivity and sensitivity for NCG-sensing applications.

Metal-Organic Frameworks for NOx Adsorption and Their Applications in Separation, Sensing, Catalysis, and Biology.

Nitrogen oxide (NOx ) is a family of poisonous and highly reactive gases formed when fuel is burned at high temperatures during anthropogenic behavior. It is a strong oxidizing agent that significantly contributes to the ozone and smog in the atmosphere. Thus, NOx removal is important for the ecological environment upon which the civilization depends. In recent decades, metal-organic frameworks (MOFs) have been regarded as ideal candidates to address these issues because they form a reticular structure between proper inorganic and organic constituents with ultrahigh porosity and high internal surface area. These characteristics render them chemically adaptable for NOx adsorption, separation, sensing, and catalysis. In additional, MOFs enable potential nitric oxide (NO) delivery for the signaling of molecular NO in the human body. Herein, the different advantages of MOFs for coping with current environmental burdens and improving the habitable environment of humans on the basis of NOx adsorption are reviewed.

Adsorption of nitrogen oxides on modified BN nanosheets: improved gas sensing and functionalization

DFT simulation of nitrogen oxide adsorption over modified defective BN nanosheets.

Electrochemical removal of NOx by La0.8Sr0.2Mn1−xNixO3 electrodes in solid electrolyte cells: Role of Ni substitution

Electrochemical removal of nitrogen oxides (NOx) by solid electrolyte cells (SECs) is a promising technology due to no required reductant. Herein, a series of La0.8Sr0.2Mn1−xNixO3 (0 ≤ x ≤ 0.5) perovskites were first synthesized and utilized as the electrode materials of SECs. The role of Ni substitution in electrode performance and NOx reduction mechanism were revealed by various experimental characterization and first-principle calculations. The results indicate that the moderate Ni substitution (x ≤ 0.3) increased the NOx conversion of electrodes while reduced the polarization resistance. The further investigation shows that this improvement was attributed to the more surface oxygen vacancies, better reducibility and higher Mn4+ proportion of the Ni-substituted perovskites. The electrochemical impedance spectroscopy (EIS) shows that these changes facilitated the NOx adsorption and dissociation processes on the electrode. According to first-principle calculations, the Ni-substituted perovskite had a lower formation energy of surface oxygen vacancy, while the NO molecule adsorbed on defect surface gained more electrons thus was easier to be reduced and dissociated. Finally, the electrode performance at different operating temperatures and the operational stability were verified.

Enhanced sensitivity of graphene nanoribbon gas sensor for detection of oxides of nitrogen using boron and phosphorus co-doped system: A first principles study

The adsorption of toxic gases Nitrogen Oxide (NO) and Nitrogen Dioxide (NO2) on armchair graphene nanoribbon substrate and its co-doped system has been investigated. Density Functional Theory (DFT) is used to explain the gas sensing performance of Boron (B) doped and Boron-Phosphorus (BP) co-doped armchair graphene nanoribbon (BCmPn-Gr; m,n = 0,1,2,3 and m + n = 3) for detection of these gases. The change in electronic and structural characteristics of armchair graphene nanoribbon (ArGNRs) before and after sensing of NO and NO2 gases is reported. Different configurations are used in our work such as Pristine, Boron doped and Boron-Phosphorus co-doped ArGNRs. Boron site is observed to be active site to study adsorption phenomenon due to accumulation of positive charge around it. Boron-Phosphorus based formation shows considerable enhancement of adsorption capabilities as compared to pristine structure alone. A significant increase in adsorption of NO and NO2 gases with increase in amount of Phosphorus atoms is observed. This work reveals that Boron Phosphorus co-doped system is considerably better than previously reported similar works. It can be utilized as effective gas sensing material.

Density functional theory researches for atomic structure, properties prediction, and rational design of selective catalytic reduction catalysts: Current progresses and future perspectives

• Using DFT to explore the adsorption of gas molecules on catalysts surface. • Investigating the characteristics of catalytic active sites and reaction mechanisms through DFT. • Explaining the catalysts poisoning process through DFT. • Illustrating the catalysts hydrothermal aging process through DFT. • Catalysts modification and design based on DFT. In recent years, molecular simulation methods, especially density functional theory (DFT), have attracted much attention and been widely used to study the SCR reaction theoretically and microscopically. This review discusses the application of DFT in SCR research from the aspects of surface adsorption, active site characteristics, reaction mechanism, poisoning mechanism, and hydrothermal aging mechanism to illustrate the status of quantum chemical computing in this field. The gas adsorption includes the adsorption of nitrogen oxides, ammonia, and their co-adsorption. The site and mechanism include the properties of different active sites, intermediate species analysis, and reaction mechanism research. The poisoning includes related research on sulfur poisoning and alkali metal poisoning. The hydrothermal aging includes research on dealumination and loss of active sites. It is demonstrated that the catalysts can be improved and rationally designed based on quantum chemistry calculations. Finally, the application of DFT in this field is evaluated, hoping to provide good suggestions for DFT calculations to further understand the more complicated reaction mechanisms and optimally design the SCR catalysts.

Pore Structure Analysis to Adsorb NOx Gas based on Porous Materials

We studied the adsorption of nitrogen oxides according to various porous materials room temperature, which can effectively to adsorb the nitrogen oxides. Based on results of measuring NOx concentration, the activated carbon materials have been shown to adsorb NOx well, and they have been shown to more efficiently removing NO2, which is very harmful to the environment. In particular, in the case of the coconut activated carbon, the removal efficiency of NO and NO2 was very excellent, and the removal rate of was 30% for 100 minutes and 19.5% for 840 minutes. Our measurement results confirmed that the activated carbon materials have a very large specific surface area and pore volume. In addition, the coconut activated carbon appears to have a large specific surface area and pore volume to remove NOx over a long period of time. Based on the experimental results, it is expected to be used as a material that efficiently removes nitrogen oxides at room temperature.