As a representative sulfur-containing volatile organic compounds (S-VOCs), CH₃SH has attracted widespread attention due to its adverse environmental and health risks. The performance of Mn-based catalysts and the effect of their crystal structure on the CH₃SH catalytic reaction have yet to be systematically investigated. In this paper, two different crystalline phases of tunneled MnO₂ (α-MnO₂ and β-MnO₂) with the similar nanorod morphology were used to remove CH₃SH, and their physicochemical properties were comprehensively studied using high-resolution transmission electron microscope (HRTEM) and electron paramagnetic resonance (EPR), H₂-TPR, O₂-TPD, Raman, and X-ray photoelectron spectroscopy (XPS) analysis. For the first time, we report that the specific reaction rate for α-MnO₂ (0.029 mol g⁻¹ h⁻¹) was approximately 4.1 times higher than that of β-MnO₂ (0.007 mol g⁻¹ h⁻¹). The as-synthesized α-MnO₂ exhibited higher CH₃SH catalytic activity towards CH₃SH than that of β-MnO₂, which can be ascribed to the additional oxygen vacancies, stronger surface oxygen migration ability, and better redox properties from α-MnO₂. The oxygen vacancies on the catalyst surface provided the main active sites for the chemisorption of CH₃SH, and the subsequent electron transfer led to the decomposition of CH₃SH. The lattice oxygen on catalysts could be released during the reaction and thus participated in the further oxidation of sulfur-containing species. CH₃SSCH₃, S⁰, SO₃²⁻, and SO₄²⁻ were identified as the main products of CH₃SH conversion. This work offers a new understanding of the interface interaction mechanism between Mn-based catalysts and S-VOCs.

The one-step reaction approach from syngas with hydrogen sulfide (CO/H₂/H₂S) over potassium (K) promoted Molybdenum disulfide (MoS₂) materials can provide alternatives for the synthesis of methanethiol (CH₃SH). However, the direct confirmation and determination of the real active nature of K-induced 2H and 1T′-MoS₂ for this reaction and the corresponding phase transformation behavior and origin of K-induced 2H-MoS₂ from/to 1T′-MoS₂ remains unclear. Herein, we proved at the atomic level the precise position of K over 1T′-MoS₂ and 2H-MoS₂ species using the technique of HAADF-STEM. A relationship between K-induced 1T′ and 2H-MoS₂ phases and the catalytic property to synthesize CH₃SH was established, and K-intercalated 1T′-MoS₂ phase was confirmed to have excellent catalytic performances. Moreover, the behavior, origin, and influencing factors of phase transformation of 2H-MoS₂ from/to 1T′-MoS₂ in the existence of K were well proved.

Steam reforming of glycerol to produce hydrogen is considered to be the very promising strategy to generate clean and renewable energy. The incipient-wetness impregnation method was used to load Ni on the reducible carrier TiO₂ (P25). In the process of catalyst preparation, the interaction and electronic effect between metal Ni and support TiO₂ were adjusted by changing the calcination temperature, and then the activity and hydrogen production of glycerol steam reforming reaction (GSR) was explored. A series of modern characterizations including XRD, UV-vis DRS, BET, XPS, NH₃-TPD, H₂-TPR, TG, and Raman have been applied to systematically characterize the catalysts. The characterization results showed that the calcination temperature can contribute to varying degrees of influences on the acidity and basicity of the Ni/TiO₂ catalyst, the specific surface area, together with the interaction force between Ni and the support. When the Ni/TiO₂ catalyst was calcined at 600 °C, the Ni species can be produced in the form of granular NiTiO₃ spinel. Consequently, due to the moderate metal–support interaction and electronic activity formed between the Ni species and the reducible support TiO₂ in the NiO/Ti-600C catalyst, the granular NiTiO₃ spinel can be reduced to a smaller Ni⁰ at a lower temperature, and thus to exhibit the best catalytic performance.

CeO₂ nanosphere-supported nickel catalysts were prepared by the wetness impregnation method and employed for hydrogen production from glycerol steam reforming. The dried catalyst precursors were either reduced by H₂ after thermal calcination or reduced by H₂ directly without calcination. The catalysts that were reduced by H₂ without calcination achieved a 95% glycerol conversion at a reaction temperature of only 475 °C, and the catalytic stability was up to 35 h. However, the reaction temperature required of catalysts reduced by H₂ with calcination was 500 °C, and the catalysts was rapidly inactivated after 25 h of reaction. A series of physicochemical characterization revealed that direct H₂ reduction without calcination enhanced the concentration of oxygen vacancies. Thus, the nickel dispersion was improved, the nickel nanoparticle size was reduced, and the reduction of nickel was increased. Moreover, the high concentration of oxygen vacancy not only contributed to the increase of H₂ yield, but also effectively reduced the amount of carbon deposition. The increased active nickel surface area and oxygen vacancies synergistically resulted in the superior catalytic performance for the catalyst that was directly reduced by H₂ without calcination. The simple, direct hydrogen reduction method remarkably boosts catalytic performance. This strategy can be extended to other supports with redox properties and applied to heterogeneous catalytic reactions involving resistance to sintering and carbon deposition.

Praseodymium (Pr)-promoted MCM-41 catalyst was investigated for the catalytic decomposition of methyl mercaptan (CH₃SH). Various characterization techniques, such as X-ray diffraction (XRD), N₂ adsorption–desorption, temperature-programmed desorption of ammonia (NH₃-TPD) and carbon dioxide (CO₂-TPD), hydrogen temperature-programmed reduction (H₂-TPR), and X-ray photoelectron spectrometer (XPS), were carried out to analyze the physicochemical properties of material. XPS characterization results showed that praseodymium was presented on the modified catalyst in the form of praseodymium oxide species, which can react with coke deposit to prolong the catalytic stability until 120 h. Meanwhile, the strong acid sites were proved to be the main active center over the 10% Pr/MCM-41 catalyst by NH₃-TPD results during the catalytic elimination of methyl mercaptan. The possible reaction mechanism was proposed by analyzing the product distribution results. The final products were mainly small-molecule products, such as methane (CH₄) and hydrogen sulfide (H₂S). Dimethyl sulfide (CH₃SCH₃) was a reaction intermediate during the reaction. Therefore, this work contributes to the understanding of the reaction process of catalytic decomposition methyl mercaptan and the design of anti-carbon deposition catalysts.