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A novel Ti-doped Ce– Sn mixed oxide (Ce–Sn–Ti) catalysts were developed for the selective catalytic reduction (SCR) of NOx with NH3. The addition of titanium could improve SCR activity at a low-temperature window. By optimizing the element proportions, the NOx conversion of Ce0.6Sn2.4Ti2 catalysts could reach more than 90% in a wide-operating temperature window (200 –450 °C). The appropriate doping Ti formed Sn–O-Ti, Sn–O-Ce and Ti–O-Ce structures, which could increase the content of Ce3+ through electrons transfer from Sn or Ti to Ce (Ce3+ + Ti4+ ↔ Ce4+ + Ti3+ and 2Ce4+ + Sn2+ ↔ 2Ce3+ + Sn4+). The solid solution structure increased specific surface areas, active sites (Ce3+), and Lewis acid sites over the Ce0.6Sn2.4Ti2 catalysts. According to DRIFTS results, only bidentate nitrate could react with adsorbed NH3 species. However, adsorbed NH3 species could quickly react with the gaseous NO. The NH3-SCR reaction mechanism over Ce0.6Sn2.4Ti2 catalysts mainly followed the Eley –Rideal mechanism. The electron transfer between tin, cerium, and titanium elements led to generate more active sites (Ce3+) used for NH3 and NOx activation/oxidation, which improved SCR activity. The NH3-SCR reaction mechanism over Ce0.6Sn2.4Ti2 catalyst mainly followed the Eley−Rideal mechanism, in which adsorbed NH3 species could quickly react with the gaseous NO to generate N2 and H2O. [ABSTRACT FROM AUTHOR]

Bimetallic catalysts have been widely employed in the lignin hydrogenolysis research, which is attributed to that the interaction between the two metals can regulate the catalyst surface properties, thus improving the catalytic performance. The metal promoters can change the adsorption strength and orientation between the catalyst surface and the substrates, the active sites dispersion and the catalyst stability, so the activity, selectivity and stability of bimetallic catalysts are better than those of the corresponding monometallic catalysts in lignin hydrogenolysis. The effects between the two metals can be divided into the following four types: the electronic (ligand) effect, synergistic effect, stabilizing effect and geometric (ensemble) effect. Herein, these four different effects between the two metals and the reaction mechanisms over different bimetallic catalysts in lignin hydrogenolysis are discussed in this minireview, aiming to point out the challenges and further perspectives in the design of efficient bimetallic catalysts. [ABSTRACT FROM AUTHOR]

Novel Mn−Eu−Fe catalysts were prepared via co‐precipitation method for NOx removal by selective catalytic reduction with NH3 (NH3−SCR). The Mn−Eu−Fe(1)‐500 catalyst possessed the highest level of low‐temperature activity, giving 98 % NO conversion at 100 °C. This catalyst also exhibited excellent H2O resistance capacity, even at a high gas hourly space velocity (GHSV) of 75,000 h−1. The NO conversion still maintained at approximately 90 % in the presence of 15 % H2O at 230 °C after 50 h, and the adverse effects of H2O could be quickly eliminated after the removal of H2O. Detailed characterization and analysis indicated that strong interactions among Mn, Eu and Fe resulted in the excellent low‐temperature SCR activity and H2O resistance of the Mn−Eu−Fe(1)‐500 catalyst. The strong interactions lead to larger specific surface area, higher concentrations of Mn4+, Fe3+ and Oα; improved redox properties, increased acid sites and acid strength, and more adsorption amounts of NO/NH3 in the presence of H2O. The Mn−Eu−Fe(1)‐500 catalyst is a potential future catalyst for low‐temperature NOx removal derived from high‐H2O‐content flue gases of natural gas combustion. [ABSTRACT FROM AUTHOR]

Nitrate with its high stability and persistence in water can pose a serious threat to both human health and aquatic ecosystems. To tackle this issue, the electrochemical nitrate reduction reaction (NO 3 RR) is considered the most effective solution for reducing excess nitrate (NO 3 –) in water and wastewater, into a value-added product ammonia (NH 3). The efficiency of NO 3 – removal during the electrochemical reduction process is directly influenced by the genuine catalysts, enable them one of the most crucial factors. The objective of this review is to elucidate the function of copper-based catalysts in the electrochemical conversion of NO 3 – to NH 3 and to identify the factors that affect the performance of these catalysts. We have also devised strategies that can be applied to enhance catalytic efficiency, along with offering an overview of the recent advancements achieved in the design of copper-based electrocatalysts. This comprehensive review will provide a detailed insight into the role of Cu-based materials in electrochemical NO 3 – reduction and the advancement of effective electrode materials for the intended reactions. [Display omitted] • A Critical Review of Fundamentals and Challenges in Electrocatalytic Reduction of Nitrate. • Cu-Based Catalysts for Electrochemical Reduction of Nitrate to Ammonia: Mechanisms and Performance. • Efficient and Selectively Electrocatalysts Based on Copper for Nitrate Reduction to Ammonia: Advancements and Prospects. • Innovative Strategies for the Development of Novel Electrocatalysts for Nitrate Reduction. • Enhancing Nitrate Electrocatalytic Reduction through Nano-Enabled Copper-Based Catalysts and Single-Atom Catalysts. [ABSTRACT FROM AUTHOR]

Cu-ZK-5 catalyst can be successfully synthesized by using inorganic templates with low cost and organic templates with low toxicity, respectively. Based on this, this paper has conducted research on the small-pore ZK-5 zeolite (KFI topology) to explore its feasibility as a diesel vehicle SCR catalyst. The T 90 and T 50 of Cu-ZK-5 catalysts prepared by organic template were 180–550 ℃ and 145 ℃, respectively. Meanwhile, the Cu-ZK-5 (org.) possesses better hydrothermal stability and better SO 2 -resistance ability. The main reasons are that the Cu-ZK-5 (org.) had higher crystallinity, more surface acid sites and isolated Cu2+ species. [Display omitted] • Cu-ZK-5 catalysts with template agents exhibited significantly different catalytic performance of NH 3 -SCR. • Cu-ZK-5 catalyst prepared by organic template has more stable framework structure. • Cu-ZK-5 catalyst synthesized by organic templates can generate more isolated Cu2+ sites and more acidic sites. [ABSTRACT FROM AUTHOR]

Cr and Zr oxides with solid solution structure are described for SCR (Selective catalytic reduction) of NO removal, and the mechanism pathway is studied. [Display omitted] • CrZrO x catalysts were the first time used in SCR of NO removal. • NO conversion of Cr 2 O 3 was significantly improved by the addition of ZrO 2 in CrZrO x catalysts. • Cr and Zr combination formed Cr-O-Zr bond as well as solid solution structure. • Structure change increased Cr6+, O a , acid sites and facilitated Langmuir-Hinshelwood mechanism. Novel CrZrO x catalysts were designed and synthesized by the co-precipitation method and the first time used for selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). The promotional effect of ZrO 2 on Cr 2 O 3 catalysts was investigated. The SCR performance of Cr 2 O 3 was significantly enhanced with the appropriate addition of ZrO 2 in CrZrO x , owing to the formation of solid solution structure and Cr-O-Zr conjunction bonds. Among the tested CrZrO x catalysts, the catalyst with Cr:Zr = 1:1 showed the optimal NO x removal efficiency at low temperatures, with the highest NO removal efficiency of 97.5% at 180 °C , excellent SO 2 and H 2 O resistance at 300 °C with 50 ppm SO 2 and 5% H 2 O. It appears that the reaction mechanisms followed the Langmuir-Hinshelwood model and NH 3 *, NH 4 +*, monodentate nitrates and nitrites were the major active intermediate species. The structure change modified the surface properties of the CrZrO x catalyst, increasing the concentrations of the acid sites, surface adsorbed oxygen O a and Cr6+, which were responsible for the enhancement of SCR performance. [ABSTRACT FROM AUTHOR]

The Fe/(SZr) and S(Fe/Zr) sulfated iron-based catalysts, prepared by impregnation methods through changing the loading order of Fe2O3 and SO42− on ZrO2, were investigated on selective catalytic reduction (SCR) of NOx by ammonia. It was studied that the existent forms of Fe2O3 and SO42− on the surface of catalysts were affected by the loading order. The Fe/(SZr) catalyst surface had isolated Fe2O3 and SO42− species and followed both the L-H mechanism and the E-R mechanism, whereas the S(Fe/Zr) catalyst contained SO42− specie and sulfate only and mainly followed the E-R pathway. These factors affected the redox ability and NH3 adsorption, which might be key to the SCR reaction. [ABSTRACT FROM AUTHOR]

The selective catalytic reduction (SCR) has been widely used in industrial denitrification owing to its high denitrification efficiency, low operating costs, and simple operating procedures. However, coal containing a large amount of sulfur will produce SO2 during combustion, which makes the catalyst easy to be deactivated, thus limiting the application of this technology. This review summarizes the latest NH3-SCR reaction mechanisms and the deactivation mechanism of catalyst in SO2-containing flue gas. Some strategies are summarized for enhancing the poison-resistance through modification, improvement of support, the preparation of complex oxide catalyst, optimizing the preparation methods, and acidification. The mechanism of improving sulfur resistance of catalysts at low temperatures is summarized, and the further development of the catalyst is also prospected. This paper could provide a reference and guidance for the development of SO2 resistance of the catalyst at low temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • The rapid synthesis was achieved by adding H 2 O 2 and seeds; • 0·.4H 2 O 2 + 20 %-2d had excellent NH 3 -SCR performance; • H 2 O 2 could facilitate the Si-O-Si bond formation; • Seeds provided the surface of growth and accelerated the crystallization process. The ZK-5 zeolite was synthesized using an eco-friendly and rapid method by incorporating H 2 O 2 and seeds, omitting the traditional organic template. And the rapidly synthesized Cu-ZK-5 catalyst exhibit excellent NH 3 -SCR performance and hydrothermal stability. The synthesis mechanism is hypothesized to result from the synergistic effects of the seeds and H 2 O 2. The seeds inclusion could avoid non-uniform nucleation during the synthesis process and promote the crystal growth and crystallization process by providing a surface for crystal growth. The innovative addition of H 2 O 2 facilitated the formation of Si-O-Si bonds, thereby accelerating the zeolite crystallization process initiated by the seeds, which resulted in a more rapid incorporation of Si into the zeolite framework. Furthermore, characterization results indicated that the rapidly synthesized samples were rich in acidic sites and active Cu2+ species, with excellent NO adsorption capacity. These features likely contributed to the enhanced NH 3 -SCR performance and hydrothermal stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Temperature drives the evolution of Ag species dynamics. • The NH 3 -SCO reaction mechanism varies at different Ag sites. • The products formed depend on the state of the Ag species. Silver-based catalysts are extensively utilized in the selective catalytic oxidation of ammonia (NH 3 -SCO). However, enhancing low-temperature activity often causes a decline in N 2 selectivity, presenting a substantial challenge in balancing activity and N 2 selectivity. In this work, we introduced zirconium into the SnO 2 support, resulting in a significant enhancement of low-temperature activity by 200 °C for the Ag/Zr 0.2 Sn 0.8 O 2 catalyst; yet, this also led to the formation of N 2 O at low temperatures and NO x at high temperatures. Characterizations such as XPS and in situ DRIFTS revealed that the dynamic changes of silver species driven by temperature had a profound impact on the reaction mechanism and guided the formation of different products. Below 200 °C, the predominance of Ag+ directed the imide mechanism, with the –HNO species being the key intermediate leading to the production of N 2 O. Above 300 °C, Ag0 became dominant, favoring the internal selective catalytic reduction (i-SCR) mechanism and the production of NO x. This work provides novel insights into improving N 2 selectivity of Ag-based catalysts and contributes to a deeper understanding of the reaction mechanisms. [ABSTRACT FROM AUTHOR]

CeO 2 has high oxygen storage and release capacity, but the surface acidity is relatively weak. However, SnO 2 with plentiful acidity can act as acid sites. So, we develop a novel CeO 2 -SnO 2 composite oxide bifunctional catalyst with high SO 2 resistance. [Display omitted] • A novel CeO 2 -SnO 2 composite oxide catalyst with high SO 2 resistance is developed. • The effects of preparation methods on the physicochemical properties of CeO 2 -SnO 2 catalyst are explored. • The catalyst prepared by coprecipitation method leads to increased surface area, acid sites and proper redox property. The selective catalytic reduction for reducing NOx with NH 3 (NH 3 -SCR) has been widespread used in denitration. Considering the shortcomings of vanadium-based catalysts, a series of novel CeO 2 -SnO 2 composite oxide catalysts with good SO 2 tolerance were developed. The effects of preparation methods on the catalytic performance had been systematically studied by characterization methods, such as XRD, SEM, N 2 adsorption–desorption, H 2 -TPR, NH 3 -TPD, XPS and in situ Fourier transform infrared spectroscopy (FTIR). Characterization results concluded that the catalytic performance was closely related to the different physicochemical property resulting from preparation methods. CeO 2 -SnO 2 composite catalyst was prepared by coprecipitation method (CeSn-CP) that displayed high NH 3 -SCR activity and good SO 2 tolerance. The coprecipitation method resulted in the high dispersion of SnO 2 species and the formation of binary solid solution. Binary solid solution was beneficial to play the synergetic effect between CeO 2 and SnO 2 , which had improved reduction ability and acidity, and thus an apparent promotion of activity was presented. [ABSTRACT FROM AUTHOR]

Description: The α-2Mo1Sn catalyst formed solid solution structure with oligomeric MoO 3 in SnO 2 lattices, which possessed strong Sn-Mo interaction and catalyzed the HDO of guaiacol into phenol with full conversion and 92.5% phenol yield. [Display omitted] • A novel hybrid Mo-Sn oxide catalyst for effective HDO of lignin derivatives into monophenols is proposed for the first time. • The α-2Mo1Sn catalyst formed solution structure with oligomeric MoO 3 in SnO 2 lattices. • The α-2Mo1Sn achieved 92.5% yield of phenol in HDO of guaiacol, higher than that of the previously reported catalysts. • Comprehensive characterizations and catalytic measurements were conducted to figure out the catalysis mechanism. Novel Mo-Sn bimetallic oxide catalysts with highly dispersed oligomeric MoO 3 in SnO 2 lattices, which were synthesized by the co-precipitation method and pretreated by anhydrous ethanol, were first employed in the hydrodeoxygenation of various lignin derivatives to produce monophenols with high activity and selectivity. In comparison with the pure α-MoO 3 and the previous reported catalysts, the α-2Mo1Sn exhibited superior activity in the hydrodeoxygenation of guaiacol, with full conversion and 92.5% phenol yield at 300 °C under 4 MPa initial H 2 pressure in n-hexane for 4 h. According to comprehensive characterizations and catalytic measurements, the excellent performance of α-2Mo1Sn was ascribed to the formation of abundant Sn-O-Mo-O V interfacial sites, which possessed strong Mo-Sn interaction with enhanced surface area, electron-donating group binding ability, Lewis acidity, and redox ability. It was demonstrated that over the present α-2Mo1Sn catalyst system, the Sn-O-Mo-O V interfacial sites could greatly facilitate the adsorption and activation of C aromatic -OCH 3 and C aromatic -CH 3 bonds, and thus significantly promote the demethoxylation and demethylation reaction to produce phenol. This work figures out the rational design of MoO 3 -based catalyst and displays a clear potential for the selective hydrodeoxygenation of lignin derivatives into monophenols. [ABSTRACT FROM AUTHOR]

Due to the intricate structure of catalysts, traditional catalyst design relies on iterative trial-and-error experiments. We have systematically established a catalyst design strategy to evaluate the performance of NH 3 -SCO reactions from the perspective of DFT calculations. Specifically, we used the catalyst formation energy as a stability descriptor and the adsorption energies of NH 3 , NH 2 , and O p-band center as performance descriptors, we identified the four most promising catalysts among 45 kinds of doped SnO 2 catalysts. Subsequently, experimental validation was performed to demonstrate the outstanding consistency between the DFT-driven descriptors and the stability and catalytic performance of the catalyst. Particularly, the Ce doping resulted in a 175 °C reduction in the T 90 compared to the SnO 2 catalyst. It is noteworthy that Ce doping promotes the cycling between oxygen vacancies and lattice oxygen, which contributes primarily to the enhancement of O 2 activation capability and, consequently, the improvement in catalytic activity. [Display omitted] • A catalyst design strategy based on DFT for NH 3 -SCO reaction has been established. • The activation of O 2 restricts the NH 3 -SCO reaction on SnO 2 catalyst. • The doping of Ce enhances the generation of surface bridging oxygen vacancies. • The synergy between oxygen vacancies and Ce promotes the activation of O 2. [ABSTRACT FROM AUTHOR]

A series modified Pt catalyst with excellent acetone catalytic oxidation activity and CO 2 selectivity through a relatively low temperature range. • Modified Pt catalyst was prepared for LTCO of acetone. • Excellent catalytic activity and CO 2 selectivity at a low temperature range. • The addition of Ce can promote the formation of more Pt0 (metal) on the support. Low temperature catalytic oxidation (LTCO) is an effective method of treatment for low concentrations of volatile organic compounds (VOCs) that uses efficient catalysts to reduce reaction activation energy and to improve reaction rates. A series of modified Pt catalysts (Pt-Ce, Pt-Zr) were successfully prepared, and they were used as catalysts for acetone oxidation. Several methods such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM) and Hydrogen-temperature-programmed reduction (H 2 -TPR) have been used to explore the reaction mechanisms between catalysts and acetone. The results show that Ce-modified Pt catalysts (Pt-Ce/TiO 2) display excellent performance for acetone oxidation, and the T 50 (temperature at 50% conversion rate) and T 90 of Pt-Ce/TiO 2 are 210 °C and 236 °C, respectively. The XPS results show that the amount of Pt0 (metal) in the Pt-Ce/TiO 2 was significantly higher than that in the Pt/TiO 2. The addition of Ce favors the formation of more Pt0 (metal) on the catalyst surface, which accelerates the acetone oxidation. It can be concluded that the additional Pt nanoparticles exposed to the catalyst surface accelerated the process of acetone oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Catalytic oxidation of acetone and benzene on Pt based catalyst was investigated. • Pt@Z and PtMn@Z catalyst showed opposite activity for VOCs. • Modulating electronic structure of Pt nanoparticles was investigated. • Removal of mixed VOCs was investigated. Revealing the role of Pt electronic structure in the catalytic degradation of VOCs is of great significance for developing efficient catalysts. Herein, the catalytic oxidation of acetone and benzene on the ZSM-5 confined Pt-based catalyst (Pt@Z) was investigated. Surprisingly, after introducing Mn to Pt@Z, the activity of the PtMn@Z catalyst for acetone was significantly increased, while the activity for benzene was decreased. It was found that Mn introduction led to electron transfer to Pt, which enhanced the adsorption of acetone and gaseous oxygen, and promoted acetone degradation. However, the high electron density of Pt inhibited the adsorption and degradation of benzene. Importantly, we used this phenomenon to regulate the electronic structure of Pt by simply adjusting the amount of Mn and achieving the synergistic removal of benzene and acetone. Therefore, this work provided an idea for the design of highly efficient catalytic materials with mixed VOCs. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are considered the culprit of secondary air pollution such as ozone, secondary organic aerosols, and photochemical smog. Among various technologies, catalytic oxidation is considered a promising method for the post-treatment of VOCs. Researchers are sparing no effort to develop novel catalysts to meet the requirements of the catalytic process. Compared with the powdered or granular catalysts, the monolithic catalysts have the advantages of low pressure drop, high utilization of active phases, and excellent mechanical properties. This review summarized the new design of monolithic catalysts (including new preparation methods, new supports, and new energy supply methods) for the post-treatment of VOCs. It addressed the advantages of the new designs in detail, and the scope of applicability for each new monolithic catalyst was also highlighted. Finally, the highly required future development trends of monolithic catalysts for VOCs catalytic oxidation are recommended. We expect this work can inspire and guide researchers from both academic and industrial communities, and help pave the way for breakthroughs in fundamental research and industrial applications in this field. The latest research progress of monolithic catalysts is divided into three parts: new preparation methods, new supports, and new energy supply methods. This manuscript addressed the advantages of these new designs in detail, and the scope of applicability for each new monolithic catalyst was also highlighted. [Display omitted] • The characteristics of the novel monolithic catalysts for VOCs are summarized. • High activity, low cost, and rapid preheating are the targets for the novel monolithic catalysts. • This review focuses on the beneficial effects of every new monolithic catalyst. • The perspectives and future challenges for the monolithic catalysts are proposed. [ABSTRACT FROM AUTHOR]

Achieving high-temperature stability/duration without compromising the activity remains an arduous task in catalyst design, particularly for MoS 2 materials. Herein, a robust catalyst with Mo doped Co 9 S 8 nanoparticles anchored on Al 2 O 3 matrix is fabricated, which could selectively convert lignin to arenes with high hydrodeoxygenation activity, selectivity and particularly excellent stability. In the hydrodeoxygenation of diphenyl ether, this catalyst afforded 99.8% conversion and 91.0% yield of benzene at 265 °C for at least 10 reaction runs. The resultant Mo-Co 9 S 8 structure with chemical connection by covalent bonds of Mo-S-Co type on the Co 9 S 8 surface demonstrates strong ability in the adsorption and activation of oxygen-containing substrates, which enables the effective C-O cleavage whilst avoids undesirable hydrogenation of benzene ring. The superior stability and water-resistance at elevated temperature was attributed to the anchoring effect of Al 2 O 3 matrix and "protection" of surface-rich Co 9 S 8 species to the active Mo-Co 9 S 8 center. This strategy provides new sights for the rational design of efficient and stable sulfide catalysts towards the applications in demanding high-temperature reactions. A facile strategy for fabricating high-temperature stable Mo-Co 9 S 8 /Al 2 O 3 catalyst was demonstrated, which could selectively convert lignin to arenes at 265 °C for at least 10 reaction runs, featuring high activity, selectivity and particularly excellent stability. [Display omitted] • High temperature stable and efficient Mo-Co 9 S 8 /Al 2 O 3 catalyst was fabricated. • Novel Mo-Co 9 S 8 structure with covalent bonds of Mo-S-Co type was formed on the Co 9 S 8 surface. • The catalyst could selectively convert lignin to arenes at 265 °C for at least 10 reaction runs. • The superior activity and stability were attributed to the formation of Mo-Co 9 S 8 center. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pt loaded MnNA monolithic catalyst were prepared for the removal of VOCs. • Pt-MnNA-P exhibited the best catalytic performance in the removal of acetone with a T 90 of 220 °C. • Pt-MnNA-P could keep its high catalytic activity for at least 48 h and exhibited excellent water resistance ability. • The reduction of Pt particle size and their high dispersion are the keys to the high activity of the Pt-MnNA-P. For large-scale application, increasing the activity of monolithic catalysts at low temperatures and achieving the high utilization efficiency of noble metal oxides remain formidable challenges. In this study, MnO 2 nanoarrays (MnNA) coated on honeycomb cordierite were prepared, and Pt nanoparticles were loaded on their surface. The probe reaction (oxidation of acetone) was set to explore their catalytic activities. By increasing the dispersion of Pt, the catalytic activity can be further improved with a T 50 of 189 °C and T 90 of 220 °C, which also exhibited water-resistance stability for 42 h. In this paper, the dispersed Pt particles can improve the activity of surface lattice oxygen of MnO 2 nanoarrays, and the possible reaction paths were subsequently discussed. This work offers a direct case for interpreting the catalytic behavior of MnNA coated on honeycomb cordierites, which could potentially promise broader insights into the construction and application of nanoarray structures in environmental engineering. [ABSTRACT FROM AUTHOR]

• 0.01 Pt-20Co/HZSM-5 exhibits excellent DCM catalytic performance. • Co could anchor Pt atoms, thus realizing the single-atom dispersion of Pt. • The formed single-atom Pt increase the oxygen vacancies on the surface of Co 3 O 4. • The synergies of Pt, Co and HZSM-5 is crucial in the catalytic process. The catalytic degradation of chlorinated volatile organic compounds (CVOCs) at low temperatures is a great challenge. In this work, Pt-Co/HZSM-5 ternary catalysts were synthesized and used for the catalytic oxidation of dichloromethane (DCM). By adding only trace amounts of Pt (0.01 wt. %), Pt-Co/HZSM-5 ternary catalyst exhibits better CO 2 yield and lower by-product yield than Co/HZSM-5 catalyst. Besides, it maintained stable activity for at least 45 h without substantial changes. The addition of water vapor to the DCM degradation process on Pt-Co/HZSM-5 ternary catalysts was shown to promote DCM conversion, CO 2 yield, and HCl yield. Catalyst characterization shows that Co (in the form of Co 3 O 4) could effectively anchor Pt atoms, thus realizing the single-atom dispersion of Pt. In turn, the formed single-atom Pt increases the proportion of oxygen vacancies on the surface of Co 3 O 4 , thereby enhancing the redox properties of Co 3 O 4. In the catalytic oxidation process, DCM first adsorbed and dechlorinated on the surface of HZSM-5 due to abundant acid sites and then completely dissociated under the interaction of Pt and Co. Thanks to the synergies of Pt, Co, and HZSM-5, Pt-Co/HZSM-5 exhibited appropriate redox ability, a suitable distribution of acid sites, and sufficient surface adsorbed oxygen, possibly explaining its lower by-product yields and the more efficient formation and desorption of HCl. [ABSTRACT FROM AUTHOR]

Description: The Ni/AC catalyst synthesized by MOCVD method exhibited high catalytic activity and selectivity in the hydrogenation of ethyl levulinate (EL) into γ-valerolactone (GVL). [Display omitted] • A novel Ni/AC catalyst was successfully prepared by metal-organic chemical vapor deposition (MOCVD) method. • The 2 wt% Ni/AC (MOCVD) presented smaller Ni nanoparticles with higher dispersion. • For the 2 wt% Ni/AC (MOCVD) catalyst, 99.7 % conversion of ethyl levulinate (EL) and 79.8 % yield of γ-valerolactone (GVL) were obtained under optimum conditions. GVL (γ-valerolactone) is identified as an important biomass platform molecule due to its wide application. In this work, a series of novel supported Ni catalysts with different supports and Ni loading were synthesized via metal-organic chemical vapor deposition (MOCVD) method for the hydrogenation of EL (ethyl levulinate) to GVL. Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), nitrogen adsorption/desorption, inductively coupled plasma optical emission spectroscopy (ICP-OES) and transmission electron microscopy (TEM) were used to characterize the as-synthesized catalysts. The results showed that the 2 wt.% Ni/AC(MOCVD) presented superior catalytic activity when compared with the catalyst prepared by impregnation method. This behavior is explained in terms of the smaller Ni nanoparticles (4.28 nm) and higher dispersion on 2 wt.% Ni/AC(MOCVD). Among the catalysts, the 2 wt.% Ni/AC catalyst exhibited the best catalytic performance with 99.7 % EL conversion and 79.8 % GVL yield under 1 MPa initial H 2 pressure (measured at room temperature) at 250 °C for 2 h. In addition, the reaction conditions were optimized and the stability of the catalyst were also investigated. The insights gained from this study in the design of high dispersed Ni particles with smaller particle size via MOCVD method will facilitate the metal-catalyzed hydrogenation of EL to GVL. [ABSTRACT FROM AUTHOR]

• The morphology and activity of the monolithic Co 3 O 4 catalysts on Ni foam are depended on reaction time, CTAB and NH 4 F. • The Co 3 O 4 @MnOx-NF presents the highest catalytic activity for VOC oxidation. • Abundant Co3+ species are generated on the Co 3 O 4 @MnOx-NF due to self-decomposition and strong oxidizing property of KMnO 4. Monolithic Co 3 O 4 and Co 3 O 4 @MnOx catalysts have been successfully prepared by in-situ growth. The morphology control and formation mechanism of Co 3 O 4 on Ni foam was investigated in detail. Among the different samples, bamboo leaf-like Co 3 O 4 -NF-10 presented good catalytic activity for acetone oxidation (T 50 = 179 °C, T 90 = 193 °C), which was attributed to its low temperature reducibility, abundant Co3+ and surface adsorbed oxygen species (O ads). Therefore, Co 3 O 4 @MnOx-NF was further prepared to obtain abundant Co3+ and O ads species due to the redox reaction between MnO 4 − and Co2+. As expected, the Co 3 O 4 @MnOx-NF catalyst presented significantly improved activity for not only acetone but ethyl acetate and toluene oxidation compared to the Co 3 O 4 -NF-10. The high catalytic performance of Co 3 O 4 @MnOx-NF was ascribed to its good low-temperature reducibility, abundant Co3+ and O ads species. In addition, Co 3 O 4 @MnOx-NF presented a satisfactory cycle and long-term stability. This work shed light on the design of monolithic catalysts in VOC oxidation. [ABSTRACT FROM AUTHOR]

The key component of the catalytic oxidation technology is regarded to develop a stable and high activity catalyst. Herein, a series of PdMn/Ti catalysts have been prepared to oxidize acetone. By controlling the Mn amount, Pd dispersion on TiO 2 has been adjusted, which has been confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The X-ray photoelectron spectroscopy (XPS) results show that catalysts possessed more adsorbed oxygen content and an increasing proportion of palladium oxides after introducing manganese with multivalent states. Hydrogen-temperature programmed reduction (H 2 -TPR) shows that the introduction of Mn has improved the low temperature reducibility of the catalyst. Catalytic activities of catalysts with manganese are much higher than that of their counterparts without manganese. Among the prepared catalysts, the Pd 0.01 Mn 0.2 /Ti catalyst exhibited the excellent catalytic activity toward acetone oxidation. The T 95 of acetone is 259 °C under the conditions of 1000 ppm of acetone concentration and 30,000 mL/(g h) of WHSV. The high catalytically activity of the Pd 0.01 Mn 0.2 /Ti catalyst could be ascribed to its good low temperature reducibility and abundant adsorbed oxygen and palladium oxides content. In addition, high valence states of Mn also contributed to the good catalytic activity of the Pd 0.01 Mn 0.2 /Ti catalyst. Unlabelled Image • Pd-based catalysts are modified by a simply and feasible method and applied successfully in acetone oxidation. • Pd-based catalysts with Mn modification have significantly enhanced catalytic activity and CO 2 yield at low temperature. • The high valence of Mn states could contribute to the improved catalytically activity of the Pd-based catalyst. [ABSTRACT FROM AUTHOR]