Journal of Catalysis最新文献

{"title":"Role of copper and cerium species in Cu/CeZSM catalysts for direct methane to methanol reaction: Insights of structure–activity relationship","authors":"Pranay Rajendra Chandewar, Debaprasad Shee","doi":"10.1016/j.jcat.2024.115916","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115916","url":null,"abstract":"The direct methane to methanol (DMTM) conversion was studied in a fixed bed reactor under varying reaction parameters including temperature, and weight hourly space velocity (WHSV) and CH₄:O₂ over several CeO₂-ZSM5, CeO₂-SiO₂ and CeO₂-Al₂O₃ supported CuO catalysts prepared by wetness impregnation method and characterized by several techniques including N₂ adsorption desorption, X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), ultraviolet visible spectroscopy (UV–vis), temperature programmed reduction (H₂-TPR), temperature programmed desorption (CO₂-TPD) and CO-diffuse reflectance infrared Fourier transform spectroscopy (CO-DRIFT) studies. The characterization results confirm the formation of bis(µ-oxo) dicopper or mono-(µ-oxo) dicopper species considered as the active sites for the DMTM reaction. Moreover, various copper (Cu²⁺, Cu⁺ and Cu⁰) and cerium (Ce³⁺ and Ce⁴⁺) species are coexisted in a redox cycle equilibrium (Cu⁺ + Ce⁴⁺ ⇌ Cu²⁺ + Ce³⁺) depending on CeO₂ loading. XPS studies indicates the generation of lattice and adsorbed oxygen species on deposition of CeO₂ and their ratio varied with the CeO₂ loading. Moreover, the different cerium species induces charge unbalance, oxygen vacancies, and formation of unsaturated chemical bonds on the catalyst’s surface. The deposition of CeO₂ and CuO incorporates more Lewis’s acid sites in xCu/yCe-ZSM5 composite catalysts and even formation of additional Lewis’s acid sites originated from exchanged copper species. The various copper and cerium species formed in the composite catalysts strongly influenced the methane molecule activation, and selectivity and yield of methanol. The surface Cu²⁺ species promotes the formation of methanol and prevents the methanol overoxidation forming oxygenates and carbon dioxide. In addition to the Cu²⁺ species, the lattice and adsorbed oxygen generated on deposition of CeO₂ also influence the formation and oxidation of methanol. Thus, optimum surface concentration of Cu²⁺ and lattice to adsorbed oxygen maximizes the yield of methanol. The process parameters also the affect the methane conversion and methanol selectivity and yield. The methanol selectivity of 6.34 % with methane conversion of 37.89 % was achieved over 20Cu/15CeZ catalysts at 873 K, 1030 ml hr^-1 gcat⁻¹ and CH₄:O₂ = 2:1. A plausible reaction mechanism of oxidation of methane to methanol based on the activity results and in-situ DRFIT studies of methanol oxidation.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"24 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Air termination of hydrocarbon-reduced Cr(Vi)/silica","authors":"Jared L. Barr, Kathy S. Clear, Masud M. Monwar, Mitchell Refvik, Max P. McDaniel","doi":"10.1016/j.jcat.2024.115904","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115904","url":null,"abstract":"The initiation of the Phillips commercial polymerization catalyst, comprising simultaneous reduction and self-alkylation of the Cr(VI), has again been examined, this time by using oxygen to terminate live Cr–alkyls formed during reduction. Cr(VI)/silica catalysts were first reduced by an alkane or alkene, then exposed to oxygen, followed by immediate hydrolysis to liberate the species thus formed. The brief exposure to oxygen significantly increased the amount of oxygenated products obtained from Cr(VI) including both monomeric and oligomeric species. This suggests that Cr–alkyls formed during reduction were converted into Cr–alkoxides or other oxygenated terminal species. This approach produces an interesting insight into the state of Cr during and shortly after initiation.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"63 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dispersity-dependent activity of Pd on bare and pre-oxidized Cu(1 1 1) surface","authors":"Jiefu Zhang, Kai Zhang, Qingqing Wang, Xiaolin Tan, Dan Wang, Xiaojun Wu, Xiang Shao","doi":"10.1016/j.jcat.2024.115919","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115919","url":null,"abstract":"Bimetallic systems can be significantly affected in terms of the catalytic activity by their compositions as well as atomic structures. This study demonstrates that the single Pd atoms and ultrasmall clusters dispersed on the surface of Cu₂O/Cu(1 1 1) exhibit significantly enhanced oxophilicity and auto-oxidizes into a checkboard-like Pd₄O₈ structure by grabbing oxygen atoms from the Cu₂O thin film. As a comparison, the Pd ad-islands on the Cu(1 1 1) surface possess compressed lattice and present a lowered activity to oxygen, but in turn enhances the oxophilicity of the Cu substrate and leads to preferential formation of cuprous oxide overlayers on the Pd islands. The drastically different oxidative reactivity of Pd on the respective Cu₂O/Cu(1<!-- --> <!-- -->1<!-- --> <!-- -->1) and Cu(1<!-- --> <!-- -->1<!-- --> <!-- -->1) surfaces dictate close correlations to their dispersion statuses. It thus provides a strategy for tuning the catalytic activities of similar bimetallic systems.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"13 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced glucose-to-5-hydroxymethylfurfural transformation activity over CePO4 catalyst: Insights into crystal structure, acidic property and reaction pathway","authors":"Yanjuan Yang, Hansheng Wang, Yuhuan Li, Zixu Yang, Jing Xu","doi":"10.1016/j.jcat.2024.115912","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115912","url":null,"abstract":"The conversion of carbohydrates to high value-added 5-hydroxymethylfurfural (5-HMF) has aroused intensive research interest. Herein, a series of cerium phosphates was prepared by simple calcination accompanied by a hexagonal-monoclinic phase transformation. Hexagonal CePO₄-200 exhibits superior catalytic activity for the conversion of glucose to 5-HMF with a yield of 73 % compared with monoclinic CePO₄-800. The related characterization results confirm that hexagonal CePO₄-200 possesses unoccupied and open spaces leading to favorable coordination environments, good pore structure and high acid density, which contributed to activation and catalysis of glucose. Density functional theory (DFT) calculations proves that the hexagonal CePO₄-200 interface possesses a more effective charge transfer ability by comparing with monoclinic CePO₄-800 interface in Lewis acidic Ce³⁺ sites region thus enhancing the catalytic activity. Additionally, a feasible tandem reaction mechanism through glucose-to-fructose isomerization driven by Ce³⁺ acidic sites and fructose dehydration to 5-HMF catalyzed by P-OH group was proposed.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"1 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photothermal CO2 conversion to cyclic carbonate over titanium-substituted polyoxometalate within covalent organic frameworks","authors":"Ziru Wang, Tian Wang, Yali Zhao, Qinghua Ye, Peilei He","doi":"10.1016/j.jcat.2024.115908","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115908","url":null,"abstract":"The fixation of CO₂ with epoxides offers a promising approach for the converting CO₂ into valuable chemicals, particularly when driven by the synergistic combination of solar energy and thermal processes. Consequently, the development of innovative and efficient catalysts for photothermal CO₂ cycloaddition under visible light irradiation is of critical importance. In this study, we encapsulated titanium-substituted polyoxometalates ([PTi₂W₁₀O₄₀]⁷⁻, abbreviated as PTi₂W₁₀) within covalent organic frameworks (COFs), specifically EB-TFP. The resulting PTi₂W₁₀@EB-TFP composite exhibits outstanding performance in photothermal catalytic CO₂ cycloaddition, offering a product yield of 98.62 %, which significantly exceeds those obtained with the individual components PTi₂W₁₀ (61.39 %) and EB-TFP (50.34 %). In-situ experiments and theoretical calculations indicate that the superior catalytic performance arises from the photothermal catalytic pathway, rather than a synergistic interaction between photocatalytic and thermal pathways. Notably, photogenerated electrons are transferred to PTi₂W₁₀, promoting the activation of the epoxide, while the electron-deficient EB-TFP facilitates CO₂ activation. This work exemplifies the utilization of polyoxometalates as photothermal catalysts for CO₂ cycloaddition, offering a sustainable and efficient strategy to chemical conversion.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"38 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinetics for Co catalyzed oxidative cyanation of biomass-based furfural","authors":"Youjie Li, Chenglong Yao, Xiaomei Wang, Jinzhu Chen, Yisheng Xu","doi":"10.1016/j.jcat.2024.115915","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115915","url":null,"abstract":"Oxidative cyanation of furfural (<strong>1a</strong>) to 2-furancarbonitrile (<strong>3a</strong>) by using NH₃ as a nitrogen source and O₂ as an oxidant is an effective strategy for biomass-based nitrile synthesis. Herein, Co catalyst supported on a nanocomposite of nitrogen-doped carbon and TiO₂ (Co/NC-TiO₂) was developed for the oxidative cyanation. The multiphase interface architecture of the catalyst enriched oxygen vacancies; moreover, the electron-rich NC nanocomponent facilitated Co²⁺/Co³⁺ valence transformation, thus promoting O₂ activation. The kinetic analysis demonstrated the condensation of <strong>1a</strong>/NH₃-to- (2-furanyl)methanimine (<strong>2a</strong>) as the rate-determining step, which was consecutively promoted by <strong>2a</strong>/O₂-to-<strong>3a</strong> dehydrogenation over the catalyst surface. A Langmuir-Hinshelwood mechanism was suggested for the oxidative dehydrogenation of the <strong>2a</strong>/O₂-to-<strong>3a</strong> step, in which O₂ is activated by an associative adsorption on the Co surface yielding a superoxide radical (O₂^•–) species for <strong>2a</strong> dehydrogenation with the release of H₂O₂. This research highlights a kinetic and mechanic understanding of the catalytic oxidative cyanation.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"22 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Au@Snβ zeolite as stable and active catalyst for the conversion of glycerol to methyl lactate","authors":"Shengqiang Zhou, Tianliang Lu, Lipeng Zhou, Xiaomei Yang","doi":"10.1016/j.jcat.2024.115913","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115913","url":null,"abstract":"Au/Sn-zeolite catalysts showed high activity for selective conversion of glycerol to methyl lactate, but suffered from poor stability under the reaction conditions in our previous report (ACS Catal. 2017, 7, 7274). Encapsulation of Au nanoparticles within zeolite is a promising strategy to enhance their stability in catalytic reaction. Herein, one-pot synthesis of Au@Snβ was achieved by a mercaptosilane-assisted hydrothermal synthesis method. The protocol involves crystallization of Snβ synthesis gels around coordinated Au precursors, resulting in Snβ framework constraining Au coordination complexes. The confinement of small (∼2.89 nm) and uniform Au particles within Snβ was achieved. The bifunctional catalyst composed of oxidative sites (Au) and Lewis acid sites (Sn) gave 77.3 % methyl lactate (MLA) yield from the base-free selective conversion of glycerol (GLY). The TOF value of Au@Snβ was higher than that of Au/Sn-zeolite in our previous report. Moreover, the special structure protects Au nanoparticles from sintering or agglomeration and improves the stability and recyclability in selective oxidation of GLY to MLA.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"18 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly stable biochar-encapsulated CoTi@BC nanocatalysts for lignin hydrogenolysis","authors":"Bowen Luo, Zhipeng Tian, Riyang Shu, Chao Wang, Ying Chen, Jianping Liu, Yuhe Liao","doi":"10.1016/j.jcat.2024.115914","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115914","url":null,"abstract":"Valorization of renewable lignin toward value-added fuels and chemicals can improve the economies of biorefinery. However, maintaining catalyst stability and preventing metal aggregation under the certain conditions of lignin hydrogenolysis remains a key challenge. Herein, hydrogenolysis of corncob enzymatic lignin was investigated using biochar-encapsulated CoTi@BC catalysts at the reaction temperature of 250 °C. Co₁Ti_0.5@BC catalyst with the addition of Ti species outperforms Co@BC catalyst, resulting in 82.5 % lignin liquefaction degree and 23.7 wt% yield of monophenols. Besides, the catalytic stability of Co₁Ti_0.5@BC catalyst is outstanding in the lignin hydrogenolysis, where almost no activity loss occurred after four recycle runs. Catalyst characterization suggests that the addition of moderate amounts of Ti species changed the reduction temperature of Co species and the interaction between metal sites and carbon layer. The uniform distribution of Ti species improves the dispersion of Co metal particles, and the carbon layer can protect the surface of metal nanoparticles from oxidation, thus maintaining the stability and the activity of Co metal sites. Furthermore, the mechanism of lignin hydrogenolysis with CoTi@BC catalysts was investigated based on the results of benzyloxyphenol hydrogenolysis. These findings demonstrate the unique advantages of biochar-encapsulated metal particles for efficient C-O bond cleavage and offer valuable insights for advancing lignin valorization and sustainable biorefinery development.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"28 2 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In-situ synthesis of a heterogeneous NHC–CO2 catalyst for continuous DMC production","authors":"Zhentao Zhao, Yuxin Wang, Guangwen Xu, Lei Shi","doi":"10.1016/j.jcat.2024.115910","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115910","url":null,"abstract":"N-heterocyclic carbene CO₂ adducts (NHC–CO₂) are typical zwitterionic ionic liquid compounds, known for their strong nucleophilicity and significant catalytic ability. However, NHC–CO₂ is sensitive to water, and its complex and polluting preparation process limits its widespread application. Furthermore, most reported NHC–CO₂ compounds function as homogeneous catalysts, posing considerable challenges for separation. In this study, an in-situ green synthesis method was employed to develop a heterogeneous NHC–CO₂ catalyst, PS–IMIL. This approach not only prevents direct contact between the catalyst and water but also simplifies the preparation process and mitigates environmental pollution. The synthesis conditions of PS–IMIL were optimized, and its structure and properties were analyzed. Furthermore, the synthesis mechanism of PS–IMIL was investigated, and its kinetics were also studied. The results indicate that the interaction between the material ethylene carbonate (EC) and the precursor is crucial for the in-situ synthesis of PS–IMIL. The prepared PS–IMIL not only preserves the catalytic ability of NHC–CO₂ but also exhibits characteristics of being metal- and halogen-free. Remarkably, the catalytic activity and structure of PS–IMIL remain unchanged after 300 h of continuous use in dimethyl carbonate (DMC) production. Compared to similar catalysts, PS–IMIL exhibits excellent catalytic activity and stability. This study provides a solid theoretical and practical reference for the development of heterogeneous NHC–CO₂ catalysts. The synthesized PS–IMIL demonstrates significant potential for the industrial production of DMC and other carbonate esters.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"201 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of surface iodine atom on dissolved oxygen activation for enhanced photocatalytic advanced oxidation processes over Bi2WO6 nanosheet","authors":"Ji-Chao Wang, Haoran Ma, Weina Shi, Wanqing Zhang, Jinyu Wang, Yuxia Hou, Xiaonan Zheng, Jingjie Liu, Junhao Zhao","doi":"10.1016/j.jcat.2024.115909","DOIUrl":"https://doi.org/10.1016/j.jcat.2024.115909","url":null,"abstract":"Facing with the growing demand of wastewater purification in industry and human being, the effect of catalyst on the activation of dissolved oxygen molecule plays a critical role for advanced oxidation processes (AOPs). Surface I atom-doped Bi₂WO₆ (I-BWO) sheet was successfully synthesized through a two-step hydrothermal method. The decomposition degradation efficiencies of p-chlorophenol and rhodamine B pollutants for the optimized 2I-BWO sample were 14.5 times and 11.0 times than those of the pristine Bi₂WO₆. The MS results about intermediates explained the mechanism of 4-CP and RhB degradation. Facing with other four organic pollutants such as methylene blue, methyl orange, 4-nitrophenol and tetracycline, the COD removal efficiencies were also observably declined through the photocatalysis. Based on experimental and computational results, the surface I atom caused the disorder of surface structure, forming superior adsorption and activation site of dissolved oxygen molecule. Multiple oxidizing species including superoxide radical, hydroxide radical, singlet oxygen and hydrogen peroxide, were proven to be generated on the modified surface of Bi₂WO₆ sheet. This study contributes to understanding the impact of in iodine doping on surface structural regulation, thereby facilitating rational design of efficient photocatalysts for AOPs.","PeriodicalId":346,"journal":{"name":"Journal of Catalysis","volume":"85 1","pages":""},"PeriodicalIF":7.3,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}