Experimental and numerical investigation of stability and emissions of hydrogen-assisted oxy-methane flames in a multi-hole model gas-turbine burner

This paper reports experimental and numerical study of stability and combustion characteristics of premixed oxy-methane flames with hydrogen-enrichment (CH₄–H₂/O₂–CO₂ flames) in a model multi-hole burner for clean energy production in gas turbines. The combustor lean blow-out (LBO) limit was presented on an equivalence ratio (Ø) - hydrogen fraction (HF: volumetric fraction of H₂ in a mixture of H₂+CH₄) map spanning over Ø-values of 0.1–1 and HF-values of 0–70% at fixed hole jet velocity and oxygen fraction (OF: volumetric fraction of O₂ in a mixture of O₂+CO₂) of 5.2 m/s and 30%, respectively. The condition of the combustion chamber is assumed to be depicted by the corrugated premixed flame regime. The premixed turbulent flame was modeled using the reaction progress variable flame front topology approach with the Large Eddy Simulation (LES) technique. The recorded combustor stability maps showed great resistance of the micromixer burner technology to flashback, recommending its use for stable gas turbine operation. The results show that H₂-enrichment widens the combustor operability limits (higher turndown ratio) by extending the LBO from Ø = 0.45 at HF = 0% down to Ø = 0.15 at HF = 70% with a slight reduction in the heat release factor by 0.1. The high reactivity and higher flame speed of H₂ ensures the sustenance of flame at lower equivalence ratios. At high equivalence ratios, H₂ addition enhances the reaction rates and makes both the primary and secondary reaction zones shorter and more intense. Increasing HF leads to increase in the Damköhler number (Da) and decrease in both the Karlovitz number (Ka) and flame thickness. The CO emission at the combustor outlet reduced significantly from 241 ppm at HF = 0% to 33.1 ppm at HF = 10%, then it increased back to 364 ppm at HF = 50%.     

The enhancement of magnetic field assisted water electrolysis hydrogen production from the compact disc recordable waste polycarbonate layer

E-waste is growing rapidly in today's data technology era while the need for green energy is critical. Current compact disc recordable (CD-R) e-waste utilization for hydrogen production by electrolysis is still classified as gray hydrogen production. This study aims to synthesize electrocatalyst for green hydrogen production from CD-R polycarbonate layer. The elemental and morphological characterizations were performed in this study along with molecular dynamics simulation and direct electrolysis experiment. The electrolysis test results shows EMF and high Bisphenol-A (BPA) content from 3 g polycarbonate produce 26000 ppm H₂ almost tripled the EMF only with 10000 ppm H₂ and doubled the EMF with 1 g polycarbonate 15000 ppm H₂. EMF and BPA cooperatively reduces water ionization energy through diamagnetic response and aromatic resonance which vibrates water molecule. Following that, the EMF slowed down OH⁻ ion movement causes the H⁺ movement towards electron become unrestricted. In conclusion, the EMF-BPA cooperation increases hydrogen evolution reaction (HER) through water ionization energy reduction and ion transfer modification.     

Impact of H2-enriched natural gas on pollutant emissions from domestic condensing boilers: numerical simulations of the combustion chamber

The addition of green hydrogen to the gas mixture feeding domestic boilers may help the ecological transition of the residential sector. However, there are concerns about the combustion process as hydrogen shows power density and reactivity that are much different than those of natural gas. In this work, we perform three-dimensional simulations with detailed kinetics to describe and comprehend the combustion process in a real modern boiler, equipped with a perforated premixed burner (presenting a pattern of small holes and slits), with the purpose also to evaluate the impact of green hydrogen. The flame structure is complex and characterized by the interaction of flames exiting from neighbor holes and slits; these flames may merge and lead to very intense flames, especially at high flow rates. The presence of a flow distributor, upstream of the burner, induces different velocities at the holes and slits, ultimately affecting the morphology, propagation and interactions of the flames. This behavior is observed for all investigated H₂ concentrations, i.e., up to 50% by vol. The model is validated against available measurements of carbon monoxide and nitric oxides in flue gases, which both indicate very satisfactory predictions. More specifically, the addition of green H₂ has a beneficial effect on both CO and NO emissions. More specifically the CO emissions at the nominal power are observed to diminish from 154 to 18 ppm when shifting from 0 to 50% H₂ in the fuel mixture, while NO emissions decrease from 20 to only 5 ppm. This latter reduction is a surprising and encouraging result; the reason is due to the fact that the addition of hydrogen in the fuel mixture leads naturally to more dilute operating conditions in a condensing boiler. We believe that the proposed model represents a valid tool to explore strategies to improve the combustion process with alternative fuels.     

Characteristics of resistivity-type hydrogen sensing based on palladium-graphene nanocomposites

We describe the characteristics of resistivity-type hydrogen (H₂) sensors made of palladium (Pd)-graphene nanocomposites. The Pd-graphene composite was synthesized by a simple chemical route capable of large production. Synthesis of Pd nanoparticles (PdNPs) of various sizes decorated on graphene flakes were easily controlled by varying the concentration of Pd precursors. Resistivity H₂ sensors were fabricated from these Pd-graphene composites and evaluated with various concentrations of H₂ and interfering gases at different temperatures. Characteristics for sensitivity, selectivity, response time and operating life were studied. The results from testing the Pd-graphene indicated a potential for hydrogen sensing materials at low temperature with good sensitivity and selectivity. Specifically H₂ was measurable with concentrations ranging from 1 to 1000 ppm in laboratory air, with a very low detection limit of 0.2 ppm. The response of the sensors is almost linear. The resistivity of sensors changed approximately 7% in its resistance with 1000 ppm H₂ even at room temperature. The robust mechanical properties of graphene, which supported these PdNPs, exhibit structural stability and durability in H₂ sensors for at least six months. Moreover, the advantages in this work are experimental reproducibility in synthesis Pd-graphene composite and sensor fabrication process.     

Decarbonisation potential of dimethyl ether/hydrogen mixtures in a flameless furnace: Reactive structures and pollutant emissions

This article sheds light on the combustion characteristics of dimethyl ether and its mixtures with methane/hydrogen under flameless conditions at different equivalence ratios. It was found that combustion of 100% dimethyl ether in flameless conditions minimises the NO formation, keeping it less than 10 ppm with no CO or unburned hydrocarbons. Progressive addition of methane was found to reduce the NO, reaching up to zero value at 50% methane in molar fraction along with a marginal CO₂ reduction. However, large amounts of CO were found for higher methane levels, greater than 60% CH₄ in molar fraction. Reactive structures based on OH1 chemiluminescence revealed that adding methane results in increased ignition delay times and, consequently, a more distributed reaction zone characterised by reduced temperature gradients. No visible flame was observed for pure dimethyl ether as well as dimethyl ether/methane mixtures. Furthermore, a more intense and narrower reaction zone, characterised by the presence of a visible flame, was formed upon hydrogen addition. Adding hydrogen by 50% in molar fraction did not cause a noticeable rise in NO levels; however, CO₂ was lowered by about 18%. Further addition of hydrogen resulted in increased peak temperatures of about 1700 K and higher NO emissions of about 50 ppm. Additionally, a skeletal Chemical Reactor Network was built and simulated with the commercial software CHEMKIN Pro to investigate the effect of the different mixtures and operating conditions on NO formation from a chemical point of view. N₂O pathway was observed to be the root source of NO emissions for pure DME and DME/CH₄ mixtures, however; the thermal pathway became gradually more important as hydrogen concentration was increased in the mixture.     

Thermodynamic characterization of H2-brine-shale wettability: Implications for hydrogen storage at subsurface

Large-scale underground hydrogen storage (UHS) appears to play an important role in the hydrogen economy supply chain, hereby supporting the energy transition to net-zero carbon emission. To understand the movement of hydrogen plume at subsurface, hydrogen wettability of storage rocks has been recently investigated from the contact angles rock-H₂-brine systems. However, hydrogen wettability of shale formations, which determines the sealing capacity of the caprock, has not been examined in detail. In this study, semi-empirical correlations were used to compute the equilibrium contact angles of H₂/brine on five shale samples with various total organic content (TOC) at various pressures (5–20 MPa) and at 343 K. The H₂ column height that can be securely trapped by the shale and capillary pressures were calculated. The shale's H₂ sealing capacity decreased with increasing pressure, increasing depth and TOC values. The CO₂/brine equilibrium contact angles were generally higher than H₂/brine equilibrium, suggesting that CO₂ could be used as favorable cushion gas to maintain formation pressure during UHS. The utmost height of H₂ that can be safely trapped by shale 3 (with TOC of 23.4 wt%) reduced from 8950 to 8750 M while that of shale 5 (with TOC of 0.081 wt%) reduced slightly from 9100 M to 9050 M as the pressure was increased from 5 to 20 MPa. The capillary entry pressure decreased with increasing depth and shale TOC, implying that the capillary trapping effect, as well as the over-pressure required to move brines from the pores by hydrogen displacement, reduces with increasing depth, and shale TOC. However, the shales remained at strongly water-wet conditions, having an equilibrium contact angles of not more than 17° at highest pressure and TOC. The study suggests that the increasing contact angles with increasing pressure and shale TOC, as well as decreasing column height and capillary pressure with increasing depth for H₂-brine-shale systems might not be sufficient to exert significant influence on structural trapping capacities of shale caprocks due to low densities of hydrogen.     

A comparative study of H2S poisoning on electrode behavior of Ni/YSZ and Ni/GDC anodes of solid oxide fuel cells

The effect of sulfur poisoning on the activity and performance of Ni/Y₂O₃–ZrO₂ (Ni/YSZ) and Ni/Gd₂O₃–CeO₂ (Ni/GDC) cermet anodes of solid oxide fuel cells has been examined by polarization and electrochemical impedance spectroscopy (EIS) measurements at 800 °C. The anodes are alternately polarized in pure H₂ and H₂S-containing H₂ fuels with H₂S concentration gradually increased from 5 ppm to 700 ppm at 200 mA cm⁻² for 2 h. The results show that the anode potential of Ni/YSZ electrodes measured in pure H₂ decreases from 0.61 V to 0.34 V after exposure to H₂S-containing H₂ fuels with H₂S concentration increased from 5 to 700 ppm. On the other hand, the anode potential of Ni/GDC electrodes measured in pure H₂ decreases from 0.78 V to 0.72 V under identical test conditions. The degradation in performance for the hydrogen oxidation in H₂S-containing H₂ fuels is substantially smaller on Ni/GDC anodes, as compared to that on Ni/YSZ anodes. Similar trend is also observed for the change of the electrode polarization resistance for the hydrogen oxidation reaction on the Ni/YSZ and Ni/GDC anodes after exposure to H₂S-containing H₂ fuels. The SEM results indicate the structure modification of Ni/YSZ anodes only occurs on Ni particles, and in the case of Ni/GDC anodes, structural modification on both Ni and GDC phases occurs. The mixed ionic and electronic conductivity of GDC phase could be the primary reason for the high sulfur tolerance of the Ni/GDC cermet anodes.     

Room temperature sensing properties of networked GaN nanowire sensors to hydrogen enhanced by the Ga2Pd5 nanodot functionalization

Multiple-networked GaN nanowires with excellent sensing properties to hydrogen were realized by functionalizing their surfaces with Ga₂Pd₅-related nanodots. Compared to the bare-GaN nanowire sensors, functionalization improved the relative resistance responses by a factor of >50 at H₂ concentrations ranging from 100 to 2000 ppm. At room temperature, the nanodot-functionalized GaN nanowire sensors exhibited a relative resistance response of 34.1% at 100 ppm H₂. Interestingly, a shell layer was transformed mostly into Ga₂Pd₅-phased nanodots, which was confirmed by X-ray diffraction and transmission electron microscopy. The mechanisms responsible for the improvement induced by nanodot functionalization are proposed in terms of the hydrogen spillover effect.     

Effect of Pd-impregnation on performance,sulfur poisoning and tolerance of Ni/GDC anode of solid oxide fuel cells

Sulfur tolerance of Ni/Gd₂O₃–CeO₂ (Ni/GDC) anodes promoted by impregnated palladium nanoparticles is investigated using the electrochemical impedance spectroscopy (EIS) and galvanostatic polarization techniques in the H₂–H₂S fuels at 800 °C. The anodes are alternately polarized in pure H₂ and H₂S-containing H₂ fuels with H₂S concentration gradually increased from 5 to 700 ppm at 200 mA cm⁻². The degradation in performance for the hydrogen oxidation in H₂S-containing H₂ fuels especially at low H₂S concentration is substantially smaller on Pd-impregnated Ni/GDC cermet anodes, as compared to that on pure Ni/GDC anodes. The potential of Pd-impregnated Ni/GDC electrodes measured in pure H₂ decreases by 0.07 V after exposure to H₂S-containing H₂ fuels, substantially smaller than 0.13 V observed on pure Ni/GDC anodes under identical test conditions. The results show that Pd impregnation significantly enhances the sulfur tolerance of Ni/GDC cermet anodes particularly in the low H₂S concentration range (e.g., <100 ppm). The results indicate that the enhanced sulfur tolerance of Pd impregnated Ni/GDC anodes is most likely due to the promotion effect of impregnated Pd nanoparticles on the hydrogen dissociation and diffusion processes. The reduced moderation of the morphology and microstructure of the anodes in the presence of Pd nanoparticles may be the result of weaker interaction or adsorption of sulfur on Ni and GDC phases.     

Two operating modes of palladium film hydrogen sensor based on suspended micro hotplate

Palladium film hydrogen sensor based on suspended micro hotplate has been fabricated to operate at elevated temperature with low power consumption. Below 150 °C, the response of the sensor to H₂ is represented by an increase in resistance. At higher temperature, the phenomenon of resistance reduction appears when it comes into contact with H₂. We have researched the reasons for this phenomenon and proposed that the sensitive mechanism is the redox reaction of Pd film on the suspended structure. The suspended substrate can affect the temperature at which redox of the Pd film occurs, and be sensitive to the changes of the surrounding gas stream. When the working temperature is 400 °C, the magnitude of response (S) changes to −0.4% within 2 s for 200 ppm H₂, and S changes to −3% within 10 s for 4000 ppm H₂. This micro hotplate based hydrogen sensor can control the range of operating temperature according to the performance requirements.     

A resonant photoacoustic cell for hydrogen gas detection

Hydrogen gas (H₂) detection plays an important role in many fields. With the continuous demand and development of clean energy, it is urgent to study new hydrogen gas sensors for stable and accurate H₂ detection. The purpose of this research is to develop a new H₂ sensor based on the resonant photoacoustic (PA) cell as the sensing element. The sensitivity of the resonant PA cell to the resonant frequency is sufficiently utilized. The optimization of its resonance frequency was investigated minutely for the H₂ sensor. Detection utilizes resonance frequency differences between H₂ and air as a sensing mechanism. The resonance frequency tracking is adopted and implemented by the field-programmable gate array (FPGA) device. The minimum detection limit of about 74 ppm for H₂ has been demonstrated by preliminary experiments. The response time of the sensor is about 5 s. This sensor detects concentrations ranging from 74 ppm to 100% in 1 atm. The preliminary test result shows that the H₂ sensor based on this structure has a larger application perspective.     

Facial fabrication of an inorganic/organic thermoelectric nanocomposite based gas sensor for hydrogen detection with wide range and reliability

A novel method for fabrication of a thermochemical hydrogen (TCH) gas sensor composed of platinum (Pt)-decorated graphene sheets and a thermoelectric (TE) polymer nanocomposite was investigated. The hydrogen sensing characterization for the device included gas response, response time (T₉₀), recovery time (D₁₀), and reliability testing, which were systematically conducted at room temperature with a relative humidity of 55%. Here, the Pt-decorated graphene sheets act as both an effective hydrogen oxidation surface and a heat-transfer TE polymer nanocomposite having low thermal conductivity. This property plays an important role in generating output voltage signal with a temperature difference between the top and bottom surfaces of the nanocomposite. As a result, our TCH gas sensor can detect the range of hydrogen from 100 ppm to percentage level with good linearity. The best response and recovery time revealed for the optimized TCH gas sensor were 23 s and 17 s under 1000 ppm H₂/air, respectively. This type of sensor can provide an important component for fabricating thermoelectric-based gas sensors with favorable gas sensing performance.     

Synthesis and characterizations of highly responsive H2S sensor using p-type Co3O4 nanoparticles/nanorods mixed nanostructures

High-quality p-type semiconducting Co₃O₄ with mixed morphology of nanoparticles/nanorods are synthesized using a hydrothermal route for high response and selective hydrogen sulphide (H₂S) sensor application. XRD and Raman studies revealed the crystal structure and molecular bonding for obtained Co₃O_4, respectively. The nanoparticles/nanorods-like structures were confirmed for Co₃O₄ using FESEM and TEM analysis. The EDS and XPS spectra analysis were carried out for elemental composition and chemical atomic states of Co₃O₄. The Co₃O₄ sensor is investigated for gas sensing properties in dynamic conditions. The sensor exhibited the highest selectivity towards H₂S among various hydrogen-contained gases at 225 °C. The sensor revealed a high response of 357% and 44% for 100 and 10 ppm H₂S gas concentrations, respectively. The Co₃O₄ sensor exhibited a systematic dynamic resistance response for 100–10 ppm range H₂S gas. The excellent dynamic resistance repeatability of the sensor was shown towards 25 ppm H₂S gas. The response of Co₃O₄ sensor was investigated at different operating temperatures and H₂S concentrations. The sensor stability and H₂S sensing mechanism for the Co₃O₄ sensor have been reported. Highly uniform and mixed nanostructures of Co₃O₄ can be the potential sensor material for real-time high-performance H₂S sensor application.     

Reactive structures and NOx emissions of methane/hydrogen mixtures in flameless combustion

Methane/hydrogen combustion represents a concrete solution for the energy scenario to come. Indeed, the addition of hydrogen into the natural gas pipeline is one of the solutions foreseen to reduce CO₂ emissions. Nevertheless, the replacement of methane by hydrogen will enhance the reactivity of the system, increasing NOx emissions. To overcome this issue, non-conventional combustion technologies, such as flameless combustion represent an attractive solution. This study aims to improve our understanding of the behaviour of methane/hydrogen blends under flameless conditions by means of experiments and simulations. Several experimental campaigns were conducted to test fuel flexibility for different methane/hydrogen blends, varying the injector geometries, equivalence ratio and dilution degree. It was found that a progressive addition of hydrogen in methane enhanced the combustion features, reducing the ignition delay time and loosing progressively the flameless behaviour of the furnace. Reducing the air injector diameter or increasing the fuel lance length were found to be efficient techniques to reduce the maximum temperature of the system and NOx emissions in the exhausts, reaching values below 30 ppm for pure hydrogen. MILD conditions were achieved up to 75%H₂ in molar fraction, with no visible flame structures. Additionally, RANS-based simulations were also conducted to shed further light on the effect of adding hydrogen into the fuel blend. A sensitivity study was conducted for three different fuel blends: pure methane, an equimolar blend and pure hydrogen. The effect of chemistry detail, mixing models, radiation modeling and turbulence models on in-flame temperatures and NOx emissions was also studied. In particular, it was found that the usage of detailed chemistry for NOx, coupled with an adjustment of the PaSR model, filled the gap between experiments and predictions. Finally, a brute-force sensitivity revealed that NNH is the most important route for NOx production.     

Review on using the depleted gas reservoirs for the underground H2 storage: A case study in Niigata prefecture,Japan

Underground hydrogen storage (UHS) in depleted hydrocarbon reservoirs is a prospective choice to store enormous volumes of hydrogen (H₂). However, these subsurface formations must be able not only to store H₂ in an effective and secure manner, but also to produce the required volumes of H₂ upon demand. This paper first reviews the critical parameters to be considered for geological analysis and reservoir engineering evaluation of UHS. The formation depth, the interactions of rock-brine-H₂, the caprock (seal) and well integrity are the most prominent parameters as far as UHS is concerned. In respect of these critical parameters, tentative H₂ storage is screened from the existing gas storage fields in the Niigata prefecture of Japan, and it was revealed that the Sekihara gas field is a suitable candidate for UHS with a storage capacity of 2.06 × 10⁸ m³ and a depth of 1000 m. Then, a series of numerical simulations utilizing CMG software was conducted to find out the extent to which critical parameters alter H₂ storage capacity. The results demonstrated that this field, with a recovery factor of 82.7% in the sixth cycle of production is a prospective site for H₂ storage.     

Simulation of 12-bed vacuum pressure-swing adsorption for hydrogen separation from methanol-steam reforming off-gas

This study focuses on analysis of a 12-bed vacuum pressure-swing adsorption (VPSA) process capable of purifying hydrogen from a ternary mixture (H₂/CO₂/CO 75/24/1 mol%) derived from methanol-steam reforming. The process produces 9 kmol H₂/h with less than 2 ppm and 0.2 ppm of CO2 and CO, respectively, to supply a polymer electrolyte membrane fuel cell. The process model is developed in Aspen Adsorption® using the “uni-bed” approach. A parametric study of H₂ purity and recovery with respect to adsorption pressure, adsorbent height, activated carbon:zeolite ratio, feed composition, and number of beds is performed. Results show 12-bed VPSA can meet the H₂ purity goals, with H₂ recovery as high as 75.75%. Adsorption occurs at 7 bar, the column height is 1.2 m, and the adsorbent ratio is 70%:30%. A 4-bed VPSA can achieve the same purity goals as the 12-bed process, but H₂ recovery decreases to 61.34%.     

Atom doping in α-Fe2O3 thin films to prevent hydrogen permeation

Prevention of hydrogen (H) penetration into passive films and steels plays a vital role in lowering hydrogen damage. This work reports effects of atom (Al, Cr, or Ni) doping on hydrogen adsorption on the α-Fe₂O₃ (001) thin films and permeation into the films based on density functional theory. We found that the H₂ molecule prefers to dissociate on the surface of pure α-Fe₂O₃ thin film with adsorption energy of −1.18 eV. Doping Al or Cr atoms in the subsurface of α-Fe₂O₃ (001) films can reduce the adsorption energy by 0.03 eV (Al) or 0.09 eV (Cr) for H surface adsorption. In contrast, Ni doping substantially enhances the H adsorption energy by 1.08 eV. As H permeates into the subsurface of the film, H occupies the octahedral interstitial site and forms chemical bond with an O atom. Comparing with H subsurface absorption in the pure film, the absorption energy decreases by 0.01–0.22 eV for the Al- and Cr-doped films, whereas increases by 0.82–0.96 eV for the Ni-doped film. These results suggest that doping Al or Cr prevents H adsorption on the surface or permeation into the passive film, which effectively reduces the possibility of hydrogen embrittlement of the underlying steel.     

Modeling study on a two-stage hydrogen purification process of pressure swing adsorption and carbon monoxide selective methanation for proton exchange membrane fuel cells

A two-stage hydrogen purification process based on pressure swing adsorption (PSA) and CO selective methanation (CO-SMET) is proposed to meet the stringent requirements of H₂-rich fuel for kW-scale skid-mounted or distributed proton exchange membrane fuel cell systems. The reforming gas is purified using dynamic adsorption model of PSA with activated carbon for initial purification and then kinetic model of CO-SMET with 50 wt% Ni/Al₂O₃ for CO deep removal. Sensitive analyses of the gas hourly space velocity, adsorption time and adsorption pressure etc. are studied. The results show that excellent H₂ purity and CO concentration below 1000 ppm for the initial target using the three-bed and four-bed PSA system at shorter adsorption time and higher pressure, and then CO concentration below 10 ppm with H₂ purity over 99.94% on CO-SMET. This work provides a small-scale and hydrogen-saving process for hydrogen purification can be achieved by the two-stage process.     

H2 PSA purifier for CO removal from hydrogen mixtures

A two-bed PSA purifier was developed to produce high purity hydrogen for fuel cell applications. Two types of hydrogen-rich mixtures produced from coal off-gas were used. Feed 1 consisted of a 99% H₂ mixture (H₂:CO:CO₂:N₂ = 99:0.1:0.05:0.85 vol.%) containing 0.1% CO while Feed 2 was a 95% H₂ mixture (H₂:CO:CO₂:CH₄:N₂ = 95:0.3:0.1:0.05:4.55 vol.%) containing 0.3% CO. An increase in the P/F ratio and adsorption pressure led to an almost linear decrease in H₂ recovery with increasing purity. However, a sharp drop in CO concentration occurred at a specific operating range in both feeds. The feed was purified to 1.1 ppm CO with 99.99+% H₂ purity and 80.0% recovery under 6.5 bar and 0.15 P/F ratio while CO in Feed 2 could be reduced to 6.7 ppm with 99.96% H₂ purity and 78.4% recovery. The PVSA process, which combined vacuum and purge steps, could improve recovery by about 10% compared to the PSA process.     

Simulation and experimental study of the NOx reduction by unburned H2 in TWC for a hydrogen engine

The unburned H₂ can be used to reduce NO emission in conventional TWC (three-way catalyst) for a hydrogen internal combustion engine when it works at equivalence ratio marginally higher than the stoichiometric ratio. To explore the effects and feasibility of this reaction, a Perfectly Stirred Reactor simulation model of TWC has been built with simplified mechanisms. Experiments on a 2.3 L turbocharged hydrogen engine are used to verify the conclusion. It shows that rising initial temperature accelerates the reduction of NO and the maximum reaction rate occurs at 400 °C temperature. The conversion efficiency of NO remains approximately 0 when temperatures below 300 °C. The efficiency reaches a peak value of approximately 98% with 400 °C and declines gradually. The unburned H₂ to NO mixing ratio greater than 1.5 in TWC guarantees 100% NO conversion efficiency. The experiments indicate that the NOx concentration decreases from 2056 ppm to 41 ppm at the stoichiometric ratio after the treatment of TWC and NOx reaches 0 ppm with a rich ratio. Results also demonstrate that the suitable reaction temperatures for TWC locate in the range of 400 °C–500 °C. Therefore, if the temperature and the mixing ratio are appropriate, it can achieve zero emissions with NOx reduction by unburned H₂ in conventional TWC for a hydrogen engine.