H2S Conversion Research Articles

Improving H2S remediation efficiency through metal-free biochar modification: Nitrogen introduction and mesopore formation

Hydrogen sulfide (H₂S) poses substantial risks to human safety and infrastructure due to its toxicity and corrosive properties. In this study, we present a novel approach to enhance the selective catalytic oxidation of H₂S by synthesizing a nitrogen-doped mesoporous carbon catalyst (denoted as M/B-X-PZ-T) through pyrolysis at 600–800 °C. Our catalyst, derived from commercial biochar, incorporates melamine as a nitrogen source and employs KCl and ZnCl₂ as porogens via the salt-templating method. The resulting catalyst, M/B-1-PZ-700, exhibits an impressive specific surface area of up to 1269.77 m²/g and a high mesopore ratio, with effective nitrogen doping reaching up to 15.35 at%. Remarkably, M/B-1-PZ-700 demonstrated exceptional performance, achieving 100 % H₂S conversion and 94 % sulfur selectivity at 170 °C, surpassing previous nitrogen-doped carbon catalysts. Furthermore, our optimized catalyst maintained over 95 % H₂S conversion and superior sulfur yield for 36 h, indicating excellent long-term stability. This metal-free catalyst derived from biochar offers a promising, sustainable, and eco-friendly solution for effectively mitigating hazardous H₂S emissions.

Enhanced decomposition of H2S to H2 via iron sulfide nanoparticles: A comprehensive experimental and theoretical evaluation

Hydrogen sulfide (H2S), a common pollutant in both fossil and bio-based fuels, can be transformed into valuable hydrogen (H2) through a two-step thermochemical process known as sulfur looping. This scheme, derived from the chemical looping approach, employs a metal-sulfide-based sulfur carrier as a solid intermediate. Iron sulfide, a benign and abundant material, is a promising candidate as the sulfur carrier; however, it faces challenges related to its poor kinetic activity. In this study, we demonstrate the exceptional performance of nano-sized sulfur carriers for the sulfur looping scheme through comprehensive experimental and theoretical analyses. We synthesized iron sulfide nanoparticles that exhibit a remarkable ∼69% enhancement in reactivity over the bulk-sized sulfur carrier. This enhancement is attributed to the high surface area and the nanoscale effects that enhance intrinsic activity. Furthermore, for the first time, we evaluated the effect of co-feeding carbon dioxide (CO2), a prevalent component in industrial acid gas streams alongside H2S. Our combined thermodynamic, atomistic density functional theory (DFT), and experimental studies indicate that the presence of CO2 enhances the conversion of H2S. Additionally, to gauge the sulfur looping process’s superiority at a larger scale, we conducted comprehensive thermodynamic analyses under industrial acid gas conditions. These analyses reveal an improvement of ∼22 percentage points in energy efficiency and ∼8 percentage points in exergy efficiency over the state-of-the-art Claus process. This study, integrating experiments, atomistic DFT studies, and process simulations, provides valuable guidance in the design of high-performance sulfur carriers for efficient H2S splitting to H2.

Sulfur modified N-doped carbocatalysts promote the selectivity for H2S selective oxidation

Sulfur element is widely applied as a non-metallic dopant into carbon framework for the modulation of their chemical activities. An interesting question is whether the intrinsic catalytic performances for the H2S selective oxidation to sulfur can be manipulated by sulfur element introduction into carbocatalysts. In this study, we employ a simple solvent-free method to introduce S atoms into framework of N-doped carbocatalysts, resulting in a notable enhancement of the product S selectivity with negligible loss of H2S selective oxidation. The experimental results show that the as-synthesized N-S-C-2 catalyst exhibits a H2S conversion of 97.5 % and sulfur selectivity of >80 % at a high O2-to-H2S ratio (2.5) under continuous mode (over the dew point temperature of sulfur, c.a. 210 °C), while also demonstrating robust stability (> 100 h), anti-CO2 (up to 50 vol%) and anti-oxidation properties. Kinetic analysis and H2S/O2-TPD-MS results reveal that S introduction attenuates the adsorption and dissociation of H2S and O2 by the N-doped carbon catalyst. Furthermore, density functional theory calculations elucidate that S doping elevates the adsorption energies of H2S and O2 at the pyridinic N site, thereby moderately reducing the adsorption of H2S and O2, consequently preventing the over-oxidation of H2S to SO2 and enhancing S selectivity. The double doping promotion effect of carbon materials reported in this investigation offers an alternative insight for the development of highly selective carbon desulfurization catalysts.

Upcycling acid waste gas containing H2S and CO2 into syngas and sulfur by non-thermal plasma coupled with Zn-Mo/Al2O3 catalyst

Synergistic conversion of H2S and CO2 into syngas and sulfur in one step, not only achieves harmless treatment, but also produces valuable chemicals, which is an ideal strategy for waste gas upcycling. Nevertheless, due to the kinetic inertia and high thermodynamic stability of H2S and CO2, the process of the reaction has not received enough attention. Non-thermal plasma has advantages over thermal processes in the process of enhanced conversion owning to its non-equilibrium properties. Herein, a novel method of non-thermal plasma coupled by Zn-Mo/Al2O3 catalyst was demonstrated for the simultaneous conversion of H2S and CO2. Furthermore, compared to the single component catalysts (ZnS/Al2O3 and MoS2/Al2O3), the Zn-Mo/Al2O3 catalysts with different Zn/Mo ratios had excellent catalytic performance. In particular, the ZM(4/4) catalyst showed complete conversion of H2S and approximately 62 % of CO2 conversion, with the highest energy efficiency of 0.95 mmol/kJ and 120 h long-term stability. Meanwhile, the mechanism of the synergistic reaction between non-thermal plasma and catalysis was revealed by means of in-situ optical emission spectrometry. This study offers a new strategy for catalyst design for the highly efficient conversion of H2S-CO2 acid waste gas via plasma-catalytic method, and highlights the synergy between Zn-Mo/Al2O3 catalyst and non-thermal plasma to promote catalytic performance.

Highly effective direct conversion of H2S into COx-free H2 and S at low temperature over novel MoxC@ZrO2 microwave catalysts

Direct decomposition of H2S into H2 and S is an attractive alternative to the Claus process, because COx-free H2 and S can be simultaneously recovered from an abundant and toxic waste gas, which has huge social economic and ecological environmental benefits. However, it is still a great challenge to achieve the direct H2S decomposition reaction with high efficiency due to the thermal equilibrium limitation. Herein, a core-shell structured MoxC@ZrO2 was developed as novel microwave catalyst for microwave catalytic H2S decomposition. More specifically, the H2S conversion over MoxC@ZrO2 catalyst is as high as 99.9% at 650 °C, which immensely surpasses the H2S equilibrium conversion (6.1% at 650 °C). This study provides an effective strategy for the design of highly active microwave catalysts, and supplies a strategy for efficiently catalytic decomposition of H2S waste and recovering high-value hydrogen and sulfur at lower reaction temperatures.

A novel cryogenic-thermochemical approach for clean hydrogen production from industrial flue gas streams with carbon capture and storage

The present work aims to develop a novel integrated energy system for clean hydrogen production from the industrial flue gas stream. The particular system incorporates a cryogenic distillation unit for H2S and CO2 separation and a thermochemical cycle for hydrogen production. The industrial flue gaseous mixture is considered a major feedstock for the present system. H2S is retrieved from the waste gaseous stream and fed to the two-step sulfur looping thermochemical cycle to perform clean hydrogen production. In this way, clean hydrogen production, elemental sulfur production, carbon capture, and storage are achieved. The entire integrated energy system is simulated in the Aspen Plus process simulator and is investigated thermodynamically in terms of energy and exergy performances. Various parametric studies are conducted to assess the significance of operating parameters on the system performance. The H2S and CO2 removal rates from the waste feed stream are found to be 85.55 % and 84.62 %. The H2S conversion into hydrogen is determined to be 66.67 %. The energy and exergy efficiencies of the two-step thermochemical cycle are found to be 53.93 % and 23.69 %, respectively. The parametric studies show that the hydrogen production rates of 3.63 kmol/h, 2.46 kmol/h, and 1.78 kmol/h are achieved at sulfurization temperatures of 200 °C, 300 °C, and 500 °C, respectively. The study further concludes that 44.60 % of the total input exergy is lost due to the presence of irreversibilities within the system. The overall energy and exergy efficiencies of the integrated energy system are found to be 82.99 % and 55.39 %, respectively.

Modeling & experimental studies on enhancement of H2S conversion using catalytic membrane reactor for hydrogen production

Abstract Acidic gases such as H2S and CO2 are generated in the refineries during coal gasification. These pollutant gases need to be treated before releasing to the atmosphere. Conventionally, H2S gas is treated by Claus process in which H2S is converted to elemental S and H2O, in presence of O2 at ∼1,200 K. In the present energy scenarios, hydrogen has got importance as a source of clean fuel for industrial application. The H2S generated in the refineries can be a potential precursor of hydrogen. If this hydrogen can be obtained by thermal decomposition of H2S, that can increase the overall economic value of the H2S containing streams and the produced hydrogen can be used for hydrocracking and hydro-treating in refineries, as well as to synthesize value-added products for chemical industries. However, H2S thermal decomposition is an endothermic and equilibrium limited reaction (equilibrium conversion is only ∼15 % at 1,000 K), requiring a very high temperature (∼1,500 K) to achieve even a conversion of greater than 40 %. Packed Bed Catalytic Membrane Reactor (PBCMR) for thermal decomposition of H2S can be a potential technology augmentation and process intensification to increase this equilibrium conversion. In this work, modeling and experimental studies of H2S thermal decomposition using in-house designed & developed PBCMR have been carried out. The modeling studies were validated with experimental data. Clay-alumina ceramic tubular membrane (L: 250 mm; OD: 12 mm; thickness: 2 mm) was fabricated using extrusion process having an average membrane pore size of ∼1 μm and with a porosity of ∼20 %. Pt (2 %) coated alumina extrudes were used as catalyst to accelerate the reaction kinetics. Experimental studies showed that H2S to hydrogen conversion of ∼90 % is achieved using PBCMR at ∼1,523 K, compared to only ∼40 % conversion in a conventional packed bed tubular reactor (without membrane). Modelling studies were carried out to study the influence of operating parameters such as, reactor wall temperature, feed temperature, pressure and feed velocity. Studies showed that reactor wall temperature is having the most dominant effect on H2S conversion, which is confirmed by experimental findings. The studies offer useful insights into the application of PBCMR technology for management of waste gas stream containing H2S and recovery of hydrogen.

Rhodoquinone-dependent electron transport chain is essential for Caenorhabditis elegans survival in hydrogen sulfide environments

Hydrogen sulfide (H2S) has traditionally been considered as an environmental toxin for animal lineages; yet, it plays a signaling role in various processes at low concentrations. Mechanisms controlling H2S in animals, especially in sulfide-rich environments, are not fully understood. The main detoxification pathway involves the conversion of H2S into less harmful forms, through a mitochondrial oxidation pathway. The first step of this pathway oxidizes sulfide and reduces ubiquinone (UQ) through sulfide-quinone oxidoreductase (SQRD/SQOR). Because H2S inhibits cytochrome oxidase and hence UQ regeneration, this pathway becomes compromised at high H2S concentrations. The free-living nematode C. elegans feeds on bacteria and can face high sulfide concentrations in its natural environment. This organism has an alternative ETC that uses rhodoquinone (RQ) as the lipidic electron transporter and fumarate as the final electron acceptor. In this study, we demonstrate that RQ is essential for survival in sulfide. RQ-less animals (kynu-1 and coq-2e KO) cannot survive high H2S concentrations, while UQ-less animals (clk-1 and coq-2a KO) exhibit recovery, even when provided with a UQ-deficient diet. Our findings highlight that sqrd-1 uses both benzoquinones and that RQ-dependent ETC confers a key advantage (RQ regeneration) over UQ in sulfide-rich conditions. C. elegans also faces cyanide, another cytochrome oxidase inhibitor, whose detoxification leads to H2S production, via cysl-2. Our study reveals that RQ delays killing by the HCN-producing bacteria Pseudomonas aeruginosa PAO1. These results underscore the fundamental role that RQ-dependent ETC serves as a biochemical adaptation to H2S environments, and to pathogenic bacteria producing cyanide and H2S toxins.

Tungsten-needle intensifies microwave-sustained plasma accelerating direct H2S conversion to H2

Direct sustainable conversion of hydrogen sulfide (H2S) enables collaborative recovery of H and S resources via a metal-enhanced microwave plasma strategy, avoiding the hydrogen waste in the traditional Claus process. However, the metal size effect on microwave plasma property, the optimal process parameters, and the enhancement mechanism remain unclear in H2S conversion. Herein, the optimal tungsten needle (diameter: 1 mm, length: 60 mm, and tip angle: 10°) is experimentally proven for intensifying microwave discharge in multi-mode cavities. Theoretical calculations and plasma distribution reveal that the optimized tungsten needle achieves the ideal coupling with the microwave field, exhibiting extreme electric field augmentation around the needle tip. Tungsten-needle intensifies microwave-sustained plasma, realizing 40.2 % (90.1 %) conversion of 100 % (10 %) concentration H2S to H2 at a low microwave power of 300 W with a good stability of 30 hrs. Low power, large flow rate, and high H2S concentration are beneficial for improving energy efficiency. The excitation of microwave plasma is accompanied by a massive generation of highly energetic electrons. The direct high-energy electron-H2S collision contributes a lot to H2S splitting, especially for high-concentration H2S. In-situ optical emission spectroscopy confirms the vital S and H radicals in the plasma. The free radical reactions triggered by electron collisions are responsible for the production of H2 and S. This work opens an avenue to sustainable and low-carbon hydrogen production from the direct conversion and utilization of H2S.

Thermodynamic Reaction Study of Conversion of H2S and CO2 and the Promoting Effect of Light on the Reaction

H2S and CO2 are common coexisted gases widely existing in natural gas resources, and they need to be treated harmlessly. The traditional Claus treatment process only focuses on H2S treatment but ignores CO2. This article systematically conducted theoretical thermodynamic research on the thermocatalytic conversion of H2S and CO2. It was found that increasing the reaction temperature and H2S ratio would have a positive impact on the reaction, while increasing the pressure would lead to a decrease in the conversion rate of reactants and product yield, and introducing COS into the feed gas could have a promoting effect on the reaction. Furthermore, 5%Mo/Al2O3 catalyst was used to preliminarily explore the thermal and photothermal catalysis for H2S and CO2 conversion. The results showed that the photothermal catalysis significantly promoted the production of syngas (H2 and CO), and suppressed COS production in contrast to thermal catalysis. This indicates that the introduction of light could effectively convert H2S and CO2 into high‐value product syngas, providing important reference value for further research on the conversion of H2S and CO2.

Unlocking the one-step recovery of solid S8 products through sulfur electro-oxidation in an acidic media

The recognized sulfur oxidation reaction (SOR) is performed in alkaline condition, and its main products of NaSx (x=1–4) are dissolvable, increasing chemical consumption to obtain solid Sx products by the multi-step recovery. Herein, the dopant of atomic carbon on MoS2 nanosheets (C-MoS2) was fabricated by chemical vapor deposition, and it can one-step convert H2S gas to solid S8 products in an acidic solution. Results showed that the yield of S8 product on C-MoS2 reached up to 2.5 kg/m2/d with a Faraday efficiency of 87.1 % at 20 mA/cm2. Moreover, theoretical and experimental studies proved that the electron density surrounding S active site increased with the incorporation of atomic C into MoS2, subsequently improving the adsorption energy of H2S and decreasing the reaction energy to obtain S8 product. Our work provides a new guideline for the SOR research on the one-step conversion of H2S to S8 solid products in acidic condition.

Mitigation of ammonia and hydrogen sulfide emissions during aerobic composting of laying hen waste through NaOH-modified biochar

The impact of NaOH-modified biochar on the release of NH3 and H2S from laying hens' manure was examined for 44 days, using a small-scale simulated aerobic composting system. The findings revealed that the NaOH-modified biochar reduced NH3 and H2S emissions by 40.63% and 77.78%, respectively, compared to the control group. Moreover, the emissions of H2S were significantly lower than those of the unmodified biochar group (p < 0.05). The increased specific surface area and microporous structure of the biochar, as well as the higher content of alkaline and oxygenated functional groups, were found to facilitate the adsorption of NH3 and H2S. This enhanced adsorption capability was the primary reason for the significant reduction in NH3 emissions. Furthermore, during the high-temperature phase of composting, there was a notable alteration in the microbial community. The abundance of Limnochordaceae, Savagea, and IMCC26207 increased significantly which aided in the conversion of H2S to stable sulfate. These microorganisms also influenced the abundance of functional genes involved in sulfur metabolism, thereby inhibiting cysteine synthesis, along with the decomposition and conversion of sulfate to sulfite. This led to a significant decrease in H2S emissions. This study provides valuable data for the selection of deodorizers in the composting process of egg-laying hens. The results have significant implications for the application of NaOH-modified biochar for odor reduction in aerobic composting processes.

Tungsten oxide nanoparticles encapsulated by porous carbon for boosting H2S selective oxidation performance

Effective advancements for H2S removal are desperately expected to meet security and ecological necessities as natural guidelines on H2S emissions. Selective catalytic oxidation, as a green technology, has attracted attention owing to its direct conversion of H2S to S without thermodynamic constraints. Herein, we report a carbon-encapsulated WO3 (C@WO3–300) catalyst with nearly 100 % H2S conversion and 99 % S selectivity. Importantly, it likewise accomplishes noteworthy catalytic stability (over 120 h of continuous operation) and water resistance. Excellent durability may be attributed to the ideal porosity of C@WO3, which facilitates the adsorption and activation of H2S and O2. Additionally, the abundant lone pair electrons of carbon support can optimize the chemical environment of WO3-based catalysts and thereby benefit the O2 activation. This study provides a new avenue for the rational design of efficient and durable catalysts for continuous catalytic oxidative desulfurization.

Modeling and simulation of a novel chemical process for clean hydrogen and power generation

The present work aims to develop a novel chemical process for clean hydrogen and power production and simulate it accordingly through a unique thermodynamic equilibrium model. This particular process is based on a partial oxidation of hydrogen sulfide (H2S) at superadiabatic conditions to study its respective chemical products. The simulation of superadiabatic partial oxidation of H2S is developed through the present model for the first time in the Aspen Plus. The process is further studied by varying different operating variables with an overall goal of optimizing the H2S conversion into hydrogen. The developed model predicts a satisfactory H2 production flow rate coupled with a low-sulfur dioxide (SO2) output within the superadiabatic partial oxidation regime at an operating pressure below 0.5 bar. The H2S conversion into H2 is then found to be 23.48 % at 0.25 bar. The overall energy and exergy efficiencies of the system are found to be 87.51 % and 70.08 % respectively. The dissociation of H2S in the presence of stoichiometric air results in elemental sulfur and hydrogen production rates of 0.0019 kg/s and 0.0012 kg/s, respectively.

Reactive regeneration in novel hybrid solvent: Achieving dual objectives of H2S conversion and absorbent regeneration

In this work, we developed a composite solution (FILs/DFP) using ionic liquids (FILs) and 4-formylmorpholine (DFP) for natural gas desulfurization. Among these, [TND-C][Tf2N]/DFP exhibited an impressive H2S uptake of 3.65 mol/mol and H2S/CO2 selectivity of 25 at 30 °C and 1 bar. The 1H NMR, FTIR, and DFT calculations revealed that the dense hydrogen bonding network and the active sites of tertiary amines in FILs/DFP were the main factors for the efficient uptake of H2S. Furthermore, we propose a viable reaction regeneration strategy at room temperature, successfully addressing the challenges of absorber regeneration, the catalytic activity of the FILs remained above 95 % even after six cycles. Overall, this strategy eliminates the high energy losses of H2S desorption and allows for the recycling of FILs with minimal energy consumption. This simultaneously achieving dual objectives of H2S conversion and absorbent regeneration process shows promising applications in natural gas desulphurization.

Engineering bifunctional sites in covalent polymers for boosting photocatalytic H2S oxidation

The development of catalyst for photocatalytic hydrogen sulfide (H2S) oxidation with excellent efficiency and regeneration properties is a significant challenge. Herein, the pyridine units as bifunctional sites are incorporated in covalent polymers (CPs) by CN coupling reaction, which exhibit photocatalytic H2S selective oxidation to sulfur conversion (95 %) under visible light in a continuous flow system, more than twice that of the pristine sample (40 %). Meanwhile, the photocatalytic H2S conversion rate had a linear function relationship with pyridinic N content, demonstrating the substantial role of pyridine in photocatalytic H2S oxidation process. According to experimental results, the pyridine unit not only acted as the structural base site to improve the H2S chemisorption, but also served as electron withdrawing unit to construct electron donor-acceptor (D-A) structure with benzene, which optimized the light absorption, charge separation and migration. In addition, series in-situ measurements and electron density difference simulations revealed the significant role of electron D-A structure in H2S adsorption and activation process. By exploring the effect of pyridine unit in CPs on H2S conversion process, this work provides a new idea for the subsequent study of photocatalytic H2S oxidation.

Parametric investigation and RSM optimization of DBD plasma methods (direct & indirect) for H2S conversion in the air

Hydrogen sulfide (H2S) is known as a harmful pollutant for the environment and human health, and its emission control is a high priority. Non-thermal plasma is an effective technology in this field. In this study, for the first time, the performance of direct and indirect H2S plasma conversion methods was compared, optimized, and modeled with the CCD method. H2S was diluted in zero air, and the study investigated the effect of discharge power, relative humidity, total flow rate, initial H2S concentration, and their interactions. ANOVA results showed that the models for H2S conversion efficiency and energy yield were significant and efficient. The direct method achieved a maximum conversion efficiency of 56 % and energy yield of 3.43 g/kWh, while the indirect method produced 68 % conversion efficiency and 1.59 g/kWh energy yield. According to the process optimization results, the direct conversion method is more optimal than the indirect conversion method due to the presence of active species and high-energy electrons in the plasma treatment, and it is a better choice if there are suitable working conditions.

Implantation of guanidine chemical adsorption sites in hyper-crosslinked polymers for effective adsorption and conversion of H2S

The efficient and selective separation of H2S is of critical scientific importance in the desulphurization of natural gas. In this work, we demonstrate a novel approach for incorporating guanidine chemical adsorption sites into hyper-crosslinked polymers (HCPs) for the first time. As expected, these HCPs exhibited excellent H2S adsorption capacity of up to 7.66 mmol·g−1 and high separation selectivity values of 133 for H2S/CO2 (0.15/0.85) and 977 for H2S/CH4 (0.15/0.85) at 25 °C and 1 bar. These HCPs maintained their structural stability after adsorbing H2S and successfully catalyzed the conversion of H2S to thiols with an approximate yield of 99 % under mild conditions. The results obtained from X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR), In-situ FTIR spectrometer (FTIR), and density functional theory (DFT) calculations validated that the HCPs achieved good selective trapping and catalytic conversion of H2S through chemisorption interaction and activation. This study provides valuable insights into the development of porous materials for efficient removal and conversion of H2S, while also highlights the potential of HCPs in gas separation and conversion.

Designed Synthesis of Fe/Zr Bimetallic Organic Framework to Enhance the Selective Conversion of H2S to Sulfur.

The development of stable and effective catalysts to convert toxic H2S into high value-added sulfur is essential for production safety and environmental protection. However, the inherent defects of traditional iron- and zirconium-based catalysts, such as poor activity, high oxygen consumption, and low sulfur selectivity, limit their further developments and applications. Herein, the Fe-Zr bimetallic organic framework FeUIO-66(x) with different cubic morphologies was synthesized via a facile solvothermal method. The results indicate that the introduction of Fe not only increases the specific surface area and weak L-sites of the catalyst without changing its crystal structure, which provides enough reaction space and more active sites for the adsorption and activation of H2S, but also reduces the activation energy of the reaction, significantly promoting the selective oxidation of H2S. As a result, the as-obtained FeUIO-66(1) catalyst exhibits the highest desulfurization activity and superior durability and water resistance stability, and its H2S conversion and sulfur selectivity within 50 h are 100 and 88%, respectively. More importantly, the structure of the catalyst after the desulfurization reaction is consistent with that of the fresh counterpart. The study offers new insights into the development of effective and stable bimetallic catalysts to eliminate H2S and recycle sulfur.

Modulating oxygen vacancies of Fe-doped Ti-based materials with ultrathin nanosheets for enhancing H2S-to-S selective oxidation

Developing highly efficient catalysts for the transformation of hydrogen sulfide (H2S) pollutants into value-added products is crucial for both fundamental catalytic research and industrial chemistry. Herein, ferrititanate nanosheets (H0.8Ti1.2Fe0.8O4, denoted as NS-HTFO) exfoliated from lepidocrocite-type titanates are employed for the first time to catalyze the conversion of H2S to elemental sulfur. Collective experimental characterizations reveal that the as-designed NS-HTFO catalyst possesses ultrathin 2D structure and a large specific surface area, featuring abundant oxygen vacancies. Compared with its sandwich-like precursor of K0.8Ti1.2Fe0.8O4 (denoted as L-KTFO), the NS-HTFO catalyst displays notably enhanced desulfurization activity, achieving 100 % H2S conversion and over 93 % sulfur selectivity at temperatures ranging from 90 to 270 °C. Moreover, no significant decline in sulfur yield is observed over the course of a 100-hour evaluation, showing outstanding breakthrough sulfur capacity up to 4163 mg/gcat. This performance exceeds that of most recently reported catalysts. The possible catalytic mechanism for H2S-to-S selective oxidation over the NS-HTFO catalyst has also been investigated.