The direct conversion of syngas to aromatics (STA) on Oxide/Zeolite bifunctional catalysts enables high selectivity for aromatic hydrocarbons. However, achieving simultaneous high CO conversion and aromatic selectivity remains big challenges for further application. The oxide component is required to demonstrate both robust and synergistic capabilities for CO activation, along with a well-matched efficiency for H2 activation. In this study, we successfully synthesized oxides with these desired characteristics through a simple lean-oxygen calcination strategy. This approach enhanced the oxygen vacancies (Ov) concentration in ZnCrOx spinels while preventing the formation of substantial amorphous ZnCrOx, which exhibits an excessively strong H2 activation capability detrimental to aromatic selectivity. The resulting Zn1Cr1.75-1%O2, when coupled with H-ZSM-5 to form a bifunctional catalyst for STA reaction, achieved a CO conversion exceeding 70% with aromatic selectivity close to 80%. Notably, it demonstrated a record space-time yield of 9.63 mmol center dot gcat-1 center dot h-1 on a carbon basis, outperforming all previously reported catalysts. Air-calcination yields an Ov-deficient ZnCrOx spinel leading to low CO conversion. N2-calcination produces an amorphous ZnCrOx oxide, resulting in low aromatic selectivity, compromised by excessive H2 activation. Lean-oxygen calcination enables the oxide to achieve balanced H2 activation capability by preventing amorphization, while significantly boosting CO conversion via abundant Ov sites.

Propane dehydroaromatization (PDA) provides a promising route to produce valuable chemicals such as benzene, toluene and xylene via non-petroleum feedstocks, in which Ga-modified MFI zeolites demonstrate high activity but are susceptible to severe coke deposition. The defect-derived silanols (Si-OH) in zeolite formed during synthesis has emerged as a predominant factor, making the prolongation of the catalyst longevity a major challenge. Here, we developed a gallosilicate MFI zeolite with silanol-defect remediated (Ga-MFI-AHFS) through an ammonium hexafluorosilicate post-treatment, which exhibited an extraordinary activity and stability. Ga-MFI-AHFS exhibits a nearly unchanged propane conversion around 82.0 % with aromatics selectivity around 64.5 % compared to a 25.4 % conversion decline on the raw zeolite with defects exposed during the 20-h CO2 assisted PDA reaction. The results of FTIR and MAS NMR showed a decreased content of silanol nests as well as the internal Si-OH groups, indicating the successful repair of silicon hydroxyl defects. The restored framework endows the Ga-MFI-AHFS zeolite with an excellent coking resistance, giving a much lower coking-rate of 5.8 × 10-8 molC/molC-in-produced-Aromatics, which is one-sixth of that on Ga-MFI. This work developed a facile route to prepare Ga-MFI zeolite with suppressed silanol-defects, which could help to realize a stable dehydroaromatization of light alkanes.

Methane (CH 4 ) serves as a commonly utilized fuel gas in various industrial and everyday settings. Given its flammable, explosive, and greenhouse gas nature, the real‐time monitoring of its concentration in the air holds vital importance across practical applications. The tetrahedral structure of methane molecules features high bond energies, posing a significant challenge for chemical detection over metal oxide‐sensitive layers. In this research, a multicomponent assembly method is used to synthesize ordered mesoporous tin oxide (SnO 2 ) with uniform large mesopores (≈ 10 nm) and pore wall functionalized with Pd x Pt nanoalloys (≈ 2.5 nm), and due to the unusual C–H bond activation capabilities of Pd x Pt nanoalloys and semiconducting properties of mesoporous SnO 2 , the obtained Pd 2 Pt@m‐SnO 2 is used to fabricate gas sensors which showcases a wide applicability range in detecting concentrations ranging from 50 to 20 000 ppm at 400 °C, and it yields a substantial CH 4 response of 9.19 (1000 ppm) and an ultralow limit of the detection value of 175.9 ppb. Furthermore, the sensor is successfully incorporated into a portable device, evidencing its capability for accurate CH 4 detection in real‐world scenarios.

The accurate identification of short-lived reaction intermediates within multitudinous molecular matrices is of vital importance for the in-depth mechanistic study of heterogeneous catalytic processes. Here we present an analytical approach employing high-speed pulsed vacuum microreactor-coupled low-energy electron impact time-of-flight mass spectrometry (HSP-LEEI-TOF-MS) for monitoring fleeting intermediates in catalytic reactions, in which a reaction conducted in near ambient pressure can be enabled through a microsecond-range reactant pulsing and the products in exit flow can be simultaneously and entirely monitored by an energy-tunable EI ionization TOF-MS, ensuring a high sensitivity in discovering intermediates and universality to investigate catalytic reactions in different scenarios. By applying this platform to propane dehydroaromatization process, a key intermediate identified as allene and/or propyne (C3H4) has been first discovered and identified over gallosilicate MFI zeolites, which is different from the transformation route of propane over aluminosilicate MFI zeolite, unveiling a concealed mechanism in which the formation of C3H4 might play a critical role in the aromatization of propane over zeolite catalysts. Our results demonstrate both the analytical power of HSP-LEEI-TOF-MS and the critical role of intermediate stabilization in determining products in alkane conversion catalysis.

The development of highly efficient and stable non-noble metal catalysts for volatile organic compound (VOCs) abatement remains a pressing challenge. Mn-based perovskites exhibit superior thermal stability as redox catalysts but suffer from limited activity in light alkane combustion. This study systematically investigates the performance of SmMnO3 (SMO) perovskite catalysts for propane oxidation through selective etching of Sm species. By precisely controlling the etching process, the removal of surface Sm exposes more active sites and significantly increases the specific surface area from 22.05 m2·g−1 for pristine SMO to 66.15 m2·g−1. SEM and N2 adsorption–desorption analysis revealed that prolonged etching induces surface roughening and pore channel expansion. XPS and XANES measurements confirmed that an increased Mn4+/Mn3+ ratio enhances reactant adsorption and accessibility to active sites. The etched catalysts exhibited markedly improved activity for propane oxidation, achieving a ~50 °C reduction in light-off temperature compared to the raw SMO. This performance enhancement is attributed to the synergistic effects of enhanced oxygen mobility, elevated Mn4+ content, and abundant oxygen vacancies. Further characterization via Raman spectroscopy and H2-TPR revealed weakened Jahn–Teller distortion and lower reduction temperatures, reflecting optimized Mn–O interactions and superior redox properties. Among the samples, SMO-20 demonstrated exceptional stability. Moreover, the SMO-20/cordierite monolithic catalyst maintained outstanding catalytic performance over 1000 h of operation. This work offers a facile and effective approach to engineer perovskite catalysts and provides new insights into structure–activity relationships in VOC oxidation.

Improving the comprehension of intricate crystallization processes at the molecular level is crucial for the customized design of efficient zeolite materials. However, the alternating dominance of classical and non-classical crystallization mechanisms, especially in multi-component solutions (monomers, oligomers, and amorphous particles), complicates mechanistic differentiation. Herein, we unveiled the structure and composition changes of ZSM-5 zeolite at various stages via selectively removing soluble species from the synthesis solution. We revealed that highly ordered, aluminum-rich subcrystals serve as essential precursors, triggering rapid non-classical aggregation growth, followed by a ripening phase dominated by single-molecule addition. Notably, aluminum species are excluded from the aggregation growth process and reincorporated via monomer addition, accounting for the compositional heterogeneity and an aluminum-enriched surface of the final product. Remarkably, for the first time, the fact and reason behind the preferential formation of aluminum-rich nuclei, as well as the changes in Al species during the rapid growth and ripening stages have well been thoroughly verified and clarified through syngas to aromatics reaction and theoretical simulations. These findings provide valuable theoretical guidance for the directional synthesis of zeolite and the control of dynamic process variables.

Exploring highly efficient and robust non-noble metal catalysts for VOC abatement is crucial but challenging. Mn-based perovskites are a class of redox catalysts with good thermal stability, but their activity in the catalytic combustion of light alkanes is insufficient. In this work, we modulated the Mn-O bond strength in a Mn-based perovskite via defect engineering, over which the catalytic activity of propane combustion was significantly enhanced. It demonstrates that the oxygen vacancy concentration and the Mn-O bond strength can be efficiently modulated by finely tuning the Ni content in SmNixMn1-xO3 perovskite catalysts (SNxM1-x), which in turn can enhance the redox ability and generate more active oxygen species. The SN0.10M0.90 catalyst with the lowest Mn-O bond strength exhibits the lowest apparent activation energy, over which the propane conversion rate increases by 3.6 times compared to that on the SmMnO3 perovskite catalyst (SM). In addition, a SN0.10M0.90/cordierite monolithic catalyst can also exhibit a remarkable catalytic performance and deliver excellent long-term durability (1000 h), indicating broad prospects in industrial applications. Moreover, the promotional effect of Ni substitution was further unveiled by density functional theory (DFT) calculations. This work brings a favorable guidance for the exploration of highly efficient perovskite catalysts for light alkane elimination.

The acidity and Ga-species status in the zeolite play a crucial role in the CO2-assisted propane dehydroaromatization (CO2-PDA). In this work, a copper modified Ga-MFI zeolite (Cu/Ga-MFI) with well dispersed framework Ga species was fabricated. A remarkable aromatics selectivity of 73% at propane conversion of 93.6% was achieved on Cu/Ga-MFI catalyst. The Ga atoms in MFI framework can create a moderate acid strength, while the introduced Cu provide an appropriate Brønsted/Lewis acid distribution, enhancing the synergy between metal-related species and the zeolite. Besides, DFT results indicate that the acid sites in Ga-MFI are more preferable for the dehydrogenation of propane instead of the C-C cleavage. Moreover, CO2 can inhibit coke formation through reverse Boudouard and reverse water gas shift reaction, which endows Cu/Ga-MFI catalyst with superior anti-coking ability and regeneration stability. This work provides a novel approach for designing catalysts with high activity, aromatics selectivity, and stability for CO2-PDA reactions.

Developing highly active and thermally stable transition-metal-oxide catalysts for light alkane catalytic oxidation is of great importance but very challenging. In the work, the catalytic performance for propane deep oxidation was significantly enhanced on the Mn1NixOy solid solution catalyst by weakening the Mn-O bond strength of manganese oxide. The characterization results combined with DFT calculations demonstrated that the introduction of Ni could create additional defect sites, resulting in a significant improvement of the adsorption and the activation of both propane and oxygen molecules. The optimal Mn1Ni0.15Oy catalyst exhibits abundant oxygen vacancies with low Mn-O bond strength, high redox ability and oxygen mobility, which account for its superior activity. Specifically, the specific reaction rate on Mn1Ni0.15Oy is three times higher than that on pure Mn2O3. Moreover, a Mn1Ni0.15Oy/cordierite monolithic catalyst was made by wash-coating method, and exhibited remarkable catalytic performance and stability on catalytic oxidation of propane during the 45 days (1080 h) on stream, even after tens of high temperature thermal shocks (up to 650 degrees C), which declared to be satisfied for practical industrial applications. This work will shed light on designing high-efficiency and long-life environmental catalyst for VOCs elimination.

Supported platinum catalysts are widely used in the catalytic combustion of volatile organic compounds due to their excellent catalytic activity, but SO2 poisoning is one of the critical problems for the industrial application. In this work, a series of sulfated ceria-zirconia composite oxides (CeZrOx) supported platinum catalysts (Pt/CeZr-S) were prepared through the support sulfation strategy. In the catalytic combustion of toluene, the Pt/CeZr-S catalyst with 0.5 wt% Pt and 15 wt% sulfuric acid loading amounts exhibited the significantly increased ac-tivity compared with the reference Pt/CeZr catalyst. Moreover, the tolerance to SO2 poisoning of Pt/CeZr-S catalyst was greatly improved in the presence of 50 ppm SO2. Various characterization methods including XPS, NH3-TPD and in-situ DRIFTS were performed to reveal the structure-activity relationship and SO2 tolerance mechanism. The higher concentration of metallic Pt0 species resulting from the interaction of Pt species and acidic CeZr-S support contributed to the enhanced catalytic activity. Meanwhile, the increased acidity strength and total acidity amounts over Pt/CeZr-S catalysts could affect the sulfation process, resulting in significant inhibition of the adsorption and further accumulation of sulfur species.

Developing efficient non-noble catalysts for low-temperature catalytic oxidation of light alkane is highly desirable and challenging. Herein, we developed a Mn1ZrxOy mixed oxide catalyst via a co-precipitation method, finding a significant promotional effect of Zr doping on the catalytic activity of MnO2 for propane oxidation. It is unraveled that doping Zr into MnO2 lattice can lead to higher redox ability and oxygen mobility, more oxygen vacancies and enhanced acidity, which are positively responsible for catalytic activity. The kinetic studies and in-situ DRIFTs revealed that the Zr doping does not change the reaction pathway, but facilitates the adsorption and activation of propane and oxygen molecules, thus accelerating the catalytic reaction. In addition, the density functional theory (DFT) calculations further confirmed the contribution of Zr doping in the adsorption of reactant molecules and the formation of oxygen vacancies. Among all, the Mn1Zr0.10Oy catalyst exhibits the highest catalytic activity with the lowest activation energy, and its reaction rate reaches 1.34 mu mol g(cat.)(-1) s(-1) at 245 degrees C, 8 times more than that of pure MnO2 catalyst. Moreover, the catalyst also displays good stability and reusability even under water vapor atmosphere.

Surface property modification of catalyst support is a straightforward approach to optimize the performance of supported noble metal catalysts. In particular, oxygen vacancies and hydroxyl groups play significant roles in promoting noble metal dispersion on catalysts as well as catalytic stability. In this study, we developed a nanoflower-like TiO2-supported Pd catalyst that has a higher concentration of oxygen vacancies and surface hydroxyl groups compared to that of commercial anatase and P25 support. Notably, due to the distinctive structure of the nanoflower-like TiO2, our catalyst exhibited improved dispersion and stabilization of Pd species and the formation of abundant reactive oxygen species, thereby facilitating the activation of CO and O2 molecules. As a result, the catalyst showed remarkable efficiency in catalyzing the low-temperature CO oxidation reaction with a complete CO conversion at 80 °C and stability for over 100 h.

Support properties regulation has been a feasible method for the improvement of noble metal catalytic performance. For Pd-based catalysts, TiO2-CeO2 material has been widely used as an important support. However, due to the considerable discrepancy in the solubility product constant between titanium and cerium hydroxides, it is still challenging to synthesize a uniform TiO2-CeO2 solid solution in the catalysts. Herein, an in situ capture strategy was constructed to fabricate a uniform TiO2-CeO2 solid solution as supports for an enhanced Pd-based catalyst. The obtained Pd/TiO2-CeO2-iC catalyst possessed enriched reactive oxygen species and optimized CO adsorption capability, manifesting a superior CO oxidation activity (T100 = 70 °C) and stability (over 170 h). We believe this work provides a viable strategy for precise characteristic modulation of composite oxide supports during the fabrication of advanced noble metal-based catalysts.

Thermo-catalytic CO2 hydrogenation with renewable energy has become one of the promising alternatives to fossil carbon-based routes for the production of bulk chemicals and has been extensively researched in recent years. And the heterogeneous oxide–zeolite (OX–ZEO) bifunctional catalysts have received much attention due to their high product selectivity. However, the need for multifunctional active sites, the complexity of tandem cascade reactions and the difficulty in understanding reaction mechanisms pose significant challenges for the design of effective catalysts. In this review, we present an overview of recent advances in the catalytic hydrogenation of CO2 to value-added products over OX–ZEO bifunctional catalysts, with particular emphasis on the role of the oxide. The nature of the metal oxide, the modification of oxides to improve catalytic performance in CO2 hydrogenation and the reaction mechanisms are discussed. Finally, the current challenges and future perspectives of the catalytic conversion of CO2 to hydrocarbons are briefly presented.

Coalbed methane is a significant source of methane in the atmosphere, which is a potent greenhouse gas with a considerable contribution to global warming, thus it is of great importance to remove methane in coalbed gas before the emission. Exploring the economical non-noble metal catalysts for catalytic methane combustion (CMC) has been a wide concern to mitigate the greenhouse effect caused by the emitted low-concentration methane. Herein, a series of Mn-doped Co3O4 catalysts have been synthesized by the environmentally friendly solid-state method. As a result, the Mn0.05Co1 catalyst performed the best CMC activity (T90 = 370 °C) and good moisture tolerance (3 vol% steam). The introduction of an appropriate amount of manganese conduced Co3O4 lattice distortion and transformed Co3+ to Co2+, thus producing more active oxygen vacancies. Mn0.05Co1 exhibited better reducibility and oxygen mobility. In situ studies revealed that methane was adsorbed and oxidized much easier on Mn0.05Co1, which is the crucial reason for its superior catalytic performance.

Syngas (CO/H2) is generally considered to be a non-petroleum carbon resource for production of liquid fuels and chemicals. Among routes of syngas conversion, the alternative to Fischer-Tropsch is a one-pass process converting syngas into value-added aromatics over metal oxides/zeolites (OX-ZEO). However, achieving high activity and high aromatics selectivity on the OX-ZEO catalysts remains a challenge. Impregnation of an appropriate amount of highly dispersed copper on CeZrOx can significantly improve CO conversion and selectivity to light aromatics. The characterizations and catalytic performance evaluations revealed that appropriate impregnation of copper on CeZrOx improves the H2 activation ability as well as effectively increases oxygen vacancy concentration. The synergistic effect of more active H and oxygen vacancy results in forming abundant oxygenated intermediate species. Furthermore, the optimal catalyst 1/200Cu-CeZrOx/ZSM-5@Si still maintains 35% CO conversion and 84% aromatics selectivity after 100 h of reaction.

As a versatile platform molecule, glycerol has been widely studied for the production of high value-added chemicals. In particular, catalytic hydrogenolysis of glycerol to 1,3-propanediol (1,3-PDO) is a highly desired route for glycerol valorization. Herein, hierarchically porous SiO2 nanospheres doped in situ with W (W-HPSN) were synthesized. The effect of the addition of short-chain alcohols (methanol, ethanol, and n-propanol) as co-solvents during the synthesis of W-HPSN on the catalytic performances of the Pt/W-HPSN catalysts in glycerol hydrogenolysis to 1,3-PDO was systematically investigated. The basic physicochemical properties, the chemical states of the active components, and the acidic properties of the catalysts were characterized by a variety of techniques. Compared with the Pt/W-HPSN-H2O catalyst prepared from W-HPSN synthesized only with water as the solvent, when the alcohols were added as the co-solvents, the specific surface area of the catalyst increased to different degrees. And aside from the micropores at 1.4 nm and the mesopores at >2 nm, new micropores appeared at 1.7 nm. In glycerol hydrogenolysis, the catalysts prepared from the W-HPSN synthesized with the addition of alcohols as the co-solvents also displayed improved glycerol conversion and 1,3-PDO selectivity, and the 1,3-PDO yields were in the order of Pt/W- HPSN- Me> Pt/ W-HPSN-Pr>Pt/W-HPSN- Et> Pt/ W-HPSN-H2O. On the best Pt/W-HPSN-Me catalyst synthesized with methanol as the co-solvent, the glycerol conversion and 1,3-PDO selectivity were 88.8% and 56.3%, respectively, in comparison to 64.1% and 40.7%, respectively, on the Pt/W-HPSN-H2O catalyst. Elemental analysis showed that the Pt and W loadings on the Pt/W-HPSN- H2O and Pt/W-HPSN-Me catalysts are identical. The X-ray photoelectron spectroscopy (XPS), Raman, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) characterizations revealed that the chemical states of the Pt and W species on the Pt/W-HPSN-H2O and Pt/W-HPSN-Me catalysts are similar. CO chemisorption and transmission electron microscopy (TEM) characterizations demonstrated that the Pt particle size on the Pt/W-HPSN-Me catalyst is smaller than that on the Pt/W-HPSN-H2O catalyst. And the cumene cracking reaction detected more in-situ generated Bronsted acid sites on the Pt/W-HPSN-Me catalyst than on the Pt/W-HPSN-H2O catalyst in H-2 atmosphere. On the basis of these characterization results, we propose that smaller Pt particle size and more in-situ generated Bronsted acid sites are conducive to a better catalytic performance of the Pt/W-HPSN catalyst. By further optimization of the composition of the W-HPSN-Me support, at the W/Si molar ratio of 1/320 and under the reaction conditions of 423 K, 4 MPa of H-2 pressure, and reaction time of only 12 h, the Pt/W-HPSN-Me catalyst afforded enhanced glycerol conversion and 1,3-PDO selectivity of 98.7% and 58.8%, respectively, thus giving rise to an outstanding 1,3-PDO yield of 58.0%. This work shows prospect for the HPSN material as an excellent catalyst support for the hydrogenolysis of glycerol to 1,3-PDO.

With the development of internet of things and artificial intelligence electronics, metal oxide semiconductor (MOS)-based sensing materials have attracted increasing attention from both fundamental research and practical applications. MOS materials possess intrinsic physicochemical properties, tunable compositions, and electronic structure, and are particularly suitable for integration and miniaturization in developing chemiresistive gas sensors. During sensing processes, the dynamic gas-solid interface interactions play crucial roles in improving sensors' performance, and most studies emphasize the gas-MOS chemical reactions. Herein, from a new view angle focusing more on physical gas-solid interactions during gas sensing, basic theory overview and latest progress for the dynamic process of gas molecules including adsorption, desorption, and diffusion, are systematically summarized and elucidated. The unique electronic sensing mechanisms are also discussed from various aspects including molecular interaction models, gas diffusion mechanism, and interfacial reaction behaviors, where structure-activity relationship and diffusion behavior are overviewed in detail. Especially, the surface adsorption-desorption dynamics are discussed and evaluated, and their potential effects on sensing performance are elucidated from the gas-solid interfacial regulation perspective. Finally, the prospect for further research directions in improving gas dynamic processes in MOS gas sensors is discussed, aiming to supplement the approaches for the development of high-performance MOS gas sensors.

Selective oxidation of higher alcohols to carbonyls is one of the most important chemical transformations in research and industrial chemistry. Gas phase selective oxidation of alcohols with air as oxidant is a "green chemistry" synthesis path, although it is a great challenge to maintain high conversion with high selectivity. In this work, we synthesized nanorod-like Mo-VOx catalysts through regulation of the Mo/V ratio via a solid-state reaction method, and the group of Mo promoted VOx catalysts exhibited the combination of high catalytic activity and selectivity. The methyl pyruvate (MP) selectivity over 0.17Mo-VOx catalysts reached 79.6% at a relatively lower reaction temperature of 180 degrees C with 90.1% methyl lactate conversion. The characterization results revealed that the 0.17Mo-VOx catalysts showed a nanorod-like morphology with larger specific surface area and smaller crystalline size, generated active MoV2O8 crystalline phase, and could give rise to active V4+/V5+ redox couples as well as surface oxygen species. In terms of structure-activity relationship, when Mo was initially introduced into VOx, the MoV2O8 phase was gradually formed, and MP yield over yMo-VOx catalysts increased significantly together with V4+ proportion. However, excessive Mo would not form more active MoV2O8 phases, and the MP yield decreased.

In the catalytic oxidation of volatile organic compounds, Co-based oxide catalysts show excellent potential and draw more and more attention, but SO2 poisoning in actual applications is one of the key problems to be solved. In this work, a series of treated halloysite (HLS)-supported Fe-modified Co oxide catalysts were prepared. In the catalytic oxidation of propane, the catalysts with 15 wt % Co loading amounts showed the best catalytic activity, while 2 wt % Fe modifications showed the best promotional effects. The introduction of Fe not only improved the catalyst activity but also enhanced the tolerance to SO2 poisoning. Various characterizations of physical-chemical properties, in situ diffuse reflectance infrared transform spectroscopy, and density functional theory calculation results showed that the active components of Co/HLS catalysts reacted with SO2 to form sulfate species, which could not provide sufficient catalytic activity afterward. The Fe species in Fe-Co/HLS catalysts could reduce the strong adsorption of SO2 on Co oxides and inhibit the formation of stable sulfate species, thus effectively reducing the effect of SO2 poisoning on the catalysts. Furthermore, the adsorption of reactants and the formation of intermediates proceeded on the surface of Fe-Co/HLS catalysts with a greater efficiency, and SO2 on the surface mainly existed in the form of surface-adsorbed SO2 species. Only a small proportion of SO2 could form SO3 species and sulfate species, thus achieving the purpose of protecting the active sites and maintaining the catalytic activity. The present study of halloysite-supported Fe-modified Co oxide catalysts would provide help for the development of Co oxide catalysts with excellent catalytic performance and tolerance to SO2 poisoning.