Pub Date : 2024-11-29DOI: 10.1016/j.cattod.2024.115147
Alberta Genco , Elisa I. García-López , Bartolomeo Megna , Conchi Ania , Giuseppe Marcì
A series of Nb2O5 semiconductors and their composites with TiO2 have been prepared following a hydrothermal treatment at varied synthetic conditions, and tested for the photoreforming of aqueous solutions of ethanol. The photo-reforming activity has been tested under UV and natural solar light irradiation, both in the absence and in the presence of Pt as co-catalyst. Our data has shown that the Nb2O5-TiO2 composite prepared by a hydrothermal treatment of three days displayed the highest photocatalytic activity, with a hydrogen production of 138 mmolH2h−1g−1 under UV light (apparent quantum yield of ca. 44 %) and 40 mmolH2kJ−1g−1 under natural solar light (apparent quantum yield of ca. 85 % considering only the UV fraction of sunlight). The exalted photocatalytic activity of this material was attributed to the concomitance of two favorable events, namely the possible formation of a heterojunction between the two semiconductors and the optimal ratio of them in this composite.
{"title":"Nb2O5 based photocatalysts for efficient generation of H2 by Photoreforming of aqueous solutions of ethanol","authors":"Alberta Genco , Elisa I. García-López , Bartolomeo Megna , Conchi Ania , Giuseppe Marcì","doi":"10.1016/j.cattod.2024.115147","DOIUrl":"10.1016/j.cattod.2024.115147","url":null,"abstract":"<div><div>A series of Nb<sub>2</sub>O<sub>5</sub> semiconductors and their composites with TiO<sub>2</sub> have been prepared following a hydrothermal treatment at varied synthetic conditions, and tested for the photoreforming of aqueous solutions of ethanol. The photo-reforming activity has been tested under UV and natural solar light irradiation, both in the absence and in the presence of Pt as co-catalyst. Our data has shown that the Nb<sub>2</sub>O<sub>5</sub>-TiO<sub>2</sub> composite prepared by a hydrothermal treatment of three days displayed the highest photocatalytic activity, with a hydrogen production of 138 mmol<sub>H2</sub>h<sup>−1</sup>g<sup>−1</sup> under UV light (apparent quantum yield of ca. 44 %) and 40 mmol<sub>H2</sub>kJ<sup>−1</sup>g<sup>−1</sup> under natural solar light (apparent quantum yield of ca. 85 % considering only the UV fraction of sunlight). The exalted photocatalytic activity of this material was attributed to the concomitance of two favorable events, namely the possible formation of a heterojunction between the two semiconductors and the optimal ratio of them in this composite.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115147"},"PeriodicalIF":5.2,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-28DOI: 10.1016/j.cattod.2024.115143
Lin Gao , Zixian Jia , Lijiao Qin , Haocheng Sun , Xinwei Zhang , Baozhong Li , Xuehai Wang , Jiquan Liu , Jinbo Bai
The recovery of Zn/ZnO nanoparticles from spent alkaline batteries was studied. This catalyst was employed for glycolysis of polyethylene terephthalate (PET) to produce bis(2-hydroxyethyl) terephthalate (BHET). The reaction temperature, catalyst/PET ratio and reaction time were investigated. Under the optimal conditions of 190 ℃ and 2 hours, with a catalyst/PET ratio of 2 %, the PET conversion rate and BHET yield of this process were 99 % and 81 %, respectively. The experimental results show that the catalyst exhibits high catalytic activity, is easy to separate, and has good reusability. In addition, this catalyst can deal effectively with impurities and dyes present in waste PET. Finally glycolysis kinetic studies were conducted on the reaction of PET degradation, and the activation energy of 118.8 kJ·mol−1 were obtained.
{"title":"Using waste to treat waste: Catalysts from spent alkaline batteries for glycolysis of PET waste","authors":"Lin Gao , Zixian Jia , Lijiao Qin , Haocheng Sun , Xinwei Zhang , Baozhong Li , Xuehai Wang , Jiquan Liu , Jinbo Bai","doi":"10.1016/j.cattod.2024.115143","DOIUrl":"10.1016/j.cattod.2024.115143","url":null,"abstract":"<div><div>The recovery of Zn/ZnO nanoparticles from spent alkaline batteries was studied. This catalyst was employed for glycolysis of polyethylene terephthalate (PET) to produce bis(2-hydroxyethyl) terephthalate (BHET). The reaction temperature, catalyst/PET ratio and reaction time were investigated. Under the optimal conditions of 190 ℃ and 2 hours, with a catalyst/PET ratio of 2 %, the PET conversion rate and BHET yield of this process were 99 % and 81 %, respectively. The experimental results show that the catalyst exhibits high catalytic activity, is easy to separate, and has good reusability. In addition, this catalyst can deal effectively with impurities and dyes present in waste PET. Finally glycolysis kinetic studies were conducted on the reaction of PET degradation, and the activation energy of 118.8 kJ·mol<sup>−1</sup> were obtained.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115143"},"PeriodicalIF":5.2,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-28DOI: 10.1016/j.cattod.2024.115146
Rocío Maderuelo-Solera , Francisco José García-Mateos , Gabriela Rodríguez-Carballo , Cristina García-Sancho , Juana María Rosas , Ramón Moreno-Tost , José Rodríguez-Mirasol , Tomás Cordero , Pedro Maireles-Torres , Juan Antonio Cecilia
Olive stones have been used to synthesize activated carbon using H3PO4 as activating agent under pyrolytic treatment. Then, Zr species have been incorporated by impregnation and subsequent calcination, obtaining acid catalysts with Lewis and Brønsted sites, which are involved in the one-pot reaction of furfural in value-added products. All catalysts display a high micro- and mesoporosity. The catalysts showed different behavior as a function of the temperature, obtaining full conversion after 24 hours at 110 ºC, being mainly selective towards furfuryl alcohol and i-propyl furfuryl ether. The study at higher temperature (170 ºC) reached the full conversion after only 45 minutes, being preferentially selective towards i-propyl levulinate and γ-valerolactone. The catalysts are prone to suffer deactivation processes due to the formation of humins on the surface of the catalysts, which cause a decrease of the available active sites.
{"title":"Zr-doped phosphorus-containing activating carbons catalysts for the valorization of furfural into valuables products in one-pot reaction","authors":"Rocío Maderuelo-Solera , Francisco José García-Mateos , Gabriela Rodríguez-Carballo , Cristina García-Sancho , Juana María Rosas , Ramón Moreno-Tost , José Rodríguez-Mirasol , Tomás Cordero , Pedro Maireles-Torres , Juan Antonio Cecilia","doi":"10.1016/j.cattod.2024.115146","DOIUrl":"10.1016/j.cattod.2024.115146","url":null,"abstract":"<div><div>Olive stones have been used to synthesize activated carbon using H<sub>3</sub>PO<sub>4</sub> as activating agent under pyrolytic treatment. Then, Zr species have been incorporated by impregnation and subsequent calcination, obtaining acid catalysts with Lewis and Brønsted sites, which are involved in the one-pot reaction of furfural in value-added products. All catalysts display a high micro- and mesoporosity. The catalysts showed different behavior as a function of the temperature, obtaining full conversion after 24 hours at 110 ºC, being mainly selective towards furfuryl alcohol and i-propyl furfuryl ether. The study at higher temperature (170 ºC) reached the full conversion after only 45 minutes, being preferentially selective towards i-propyl levulinate and γ-valerolactone. The catalysts are prone to suffer deactivation processes due to the formation of humins on the surface of the catalysts, which cause a decrease of the available active sites.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115146"},"PeriodicalIF":5.2,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143179877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-25DOI: 10.1016/j.cattod.2024.115145
Jiamin Wang , Shanhui Zhu , Zexiang Lv , Xiangyu Jia , Xiaoming Li , Mei Dong , Weibin Fan
Selective cleavage of C–O bond in biomass-derived furfuryl alcohol (FFA), with complex chemical functional groups, poses a great challenge to biomass upgrading. In this work, Pt/Mg2AlO catalysts were prepared by urea hydrolysis (Pt-HT), coprecipitation (Pt-CP) and sol-gel (Pt-SG) methods to study the interfacial property caused by support synthesis methods during selective hydrogenation of FFA to 1,2-pentanediol (1,2-PeD). The results clearly showed that 1,2-PeD yield on Pt-HT was 60.3 %, better than those on Pt-CP and Pt-SG catalysts. The superior catalytic activity of Pt-HT is ascribed to effective adsorption and split of C–O bonds, facilitated by plentiful interfacial oxygen vacancies and Pt0 species. Furthermore, the superior selectivity of 1,2-PeD is related to the deforming non-parallel adsorption mode of FFA rings on Pt-HT resulting from their interaction with interfacial oxygen vacancies.
{"title":"Selective hydrogenation of furfuryl alcohol to 1,2-pentanediol over Pt/Mg2AlO catalysts with different synthesis methods","authors":"Jiamin Wang , Shanhui Zhu , Zexiang Lv , Xiangyu Jia , Xiaoming Li , Mei Dong , Weibin Fan","doi":"10.1016/j.cattod.2024.115145","DOIUrl":"10.1016/j.cattod.2024.115145","url":null,"abstract":"<div><div>Selective cleavage of C–O bond in biomass-derived furfuryl alcohol (FFA), with complex chemical functional groups, poses a great challenge to biomass upgrading. In this work, Pt/Mg<sub>2</sub>AlO catalysts were prepared by urea hydrolysis (Pt-HT), coprecipitation (Pt-CP) and sol-gel (Pt-SG) methods to study the interfacial property caused by support synthesis methods during selective hydrogenation of FFA to 1,2-pentanediol (1,2-PeD). The results clearly showed that 1,2-PeD yield on Pt-HT was 60.3 %, better than those on Pt-CP and Pt-SG catalysts. The superior catalytic activity of Pt-HT is ascribed to effective adsorption and split of C–O bonds, facilitated by plentiful interfacial oxygen vacancies and Pt<sup>0</sup> species. Furthermore, the superior selectivity of 1,2-PeD is related to the deforming non-parallel adsorption mode of FFA rings on Pt-HT resulting from their interaction with interfacial oxygen vacancies.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115145"},"PeriodicalIF":5.2,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1016/j.cattod.2024.115134
Katiúscia M. Nobre Borba , Letícia Guerreiro da Trindade , Letícia Zanchet , Sibele Pergher , Urbano Diaz , Fernando Rey Garcia , Katia Bernardo-Gusmão
The use of MCM-41 led to the development of a silylated hybrid material (MS), which in turn played a crucial role in obtaining semiconducting polyphenylacetylene, with a conductivity of 8.13 × 10−5 S m−1. MS was also responsible for reducing the polyphenylacetylene band gap from 2.13 eV to 1.83 eV. When used in a capacitor, polyphenylacetylene exhibited stability after 3000 charge/discharge cycles and a capacitance seven times higher than that of poly(o-methoxyaniline) (POMA) polymer.
MCM-41的使用导致了硅烷化杂化材料（MS）的发展，这反过来又在获得导电率为8.13 × 10−5 S m−1的半导体聚苯乙炔方面发挥了关键作用。MS还能将聚苯乙炔的带隙从2.13 eV减小到1.83 eV。当用作电容器时，聚苯乙炔在3000次充放电循环后表现出稳定性，其电容比聚邻甲氧基苯胺（POMA）聚合物高7倍。
{"title":"Novel preparation of polyphenylacetylene semiconductor: Potential application in supercapacitors","authors":"Katiúscia M. Nobre Borba , Letícia Guerreiro da Trindade , Letícia Zanchet , Sibele Pergher , Urbano Diaz , Fernando Rey Garcia , Katia Bernardo-Gusmão","doi":"10.1016/j.cattod.2024.115134","DOIUrl":"10.1016/j.cattod.2024.115134","url":null,"abstract":"<div><div>The use of MCM-41 led to the development of a silylated hybrid material (MS), which in turn played a crucial role in obtaining semiconducting polyphenylacetylene, with a conductivity of 8.13 × 10<sup>−5</sup> S m<sup>−1</sup>. MS was also responsible for reducing the polyphenylacetylene band gap from 2.13 eV to 1.83 eV. When used in a capacitor, polyphenylacetylene exhibited stability after 3000 charge/discharge cycles and a capacitance seven times higher than that of poly(o-methoxyaniline) (POMA) polymer.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115134"},"PeriodicalIF":5.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142757804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a systematic theoretical study on the applicability of the hybrid Cun-TiO2 systems (n = 1 – 7) for photo electrochemical hydrogen evolution reaction. The preferred binding sites for hydrogen atom are determined. The hydrogen adopts a Cu-H-Ti bridging position when bound to Cu1-(TiO2)34 or Cu7-(TiO2)34 or Cu-H-Cu when bound to Cu2-(TiO2)34 or Cu4-(TiO2)34. In Cun-(TiO2)34 with n = 3, 5, 6 the H atom sits in the three coordinate site, similar to that found for its favourable position while on Cu(111). The population analysis reveals that in the selected cases, n = 1, 2, 5, 7, the hydrogen binding exhibits three centre two electron bond character. In all the cases studied here the adsorbate has a hydride character. Among the studied clusters, those containing 1, 4, and 7 copper atoms exhibit moderate Gibbs free H binding energies indicating them as the best candidates for hydrogen evolution. The obtained results are compared with data available in literature for metallic copper and other materials having isolated single Cu atom sites. Considering Cu atom efficiency as well as wide availability and use of the titania as a support, these materials may be competitive for H2 generation.
{"title":"Single atom and sub-nanometer copper clusters deposited on titania for hydrogen evolution reaction: A density functional study","authors":"Dorota Rutkowska-Zbik , Vidya Kaipanchery , Renata Tokarz-Sobieraj","doi":"10.1016/j.cattod.2024.115142","DOIUrl":"10.1016/j.cattod.2024.115142","url":null,"abstract":"<div><div>We present a systematic theoretical study on the applicability of the hybrid Cu<sub>n</sub>-TiO<sub>2</sub> systems (n = 1 – 7) for photo electrochemical hydrogen evolution reaction. The preferred binding sites for hydrogen atom are determined. The hydrogen adopts a Cu-H-Ti bridging position when bound to Cu<sub>1</sub>-(TiO<sub>2</sub>)<sub>34</sub> or Cu<sub>7</sub>-(TiO<sub>2</sub>)<sub>34</sub> or Cu-H-Cu when bound to Cu<sub>2</sub>-(TiO<sub>2</sub>)<sub>34</sub> or Cu<sub>4</sub>-(TiO<sub>2</sub>)<sub>34</sub>. In Cu<sub>n</sub>-(TiO<sub>2</sub>)<sub>34</sub> with n = 3, 5, 6 the H atom sits in the three coordinate site, similar to that found for its favourable position while on Cu(111). The population analysis reveals that in the selected cases, n = 1, 2, 5, 7, the hydrogen binding exhibits three centre two electron bond character. In all the cases studied here the adsorbate has a hydride character. Among the studied clusters, those containing 1, 4, and 7 copper atoms exhibit moderate Gibbs free H binding energies indicating them as the best candidates for hydrogen evolution. The obtained results are compared with data available in literature for metallic copper and other materials having isolated single Cu atom sites. Considering Cu atom efficiency as well as wide availability and use of the titania as a support, these materials may be competitive for H<sub>2</sub> generation.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"446 ","pages":"Article 115142"},"PeriodicalIF":5.2,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.cattod.2024.115141
Kelly C.N.R. Pedro , Gabrielle A.R. da Silva , Mônica A.P. da Silva , Cristiane A. Henriques , Marta A.P. Langone
Lipases have been immobilized on various supports to catalyze hydrolysis, esterification, and transesterification reactions efficiently. Among a broad range of materials, mesoporous silica has attracted attention thanks to its distinct characteristics and advantages, being widely used for biocatalysis applications. In this work, the lipase from Thermomyces lanuginosus (TLL) was immobilized on six different carriers: two zeolites HZSM-5 (SAR 25 and 280), mesoporous Si-MCM-41, and silica-aluminas Siral 10, 20, and 40. TLL was efficiently immobilized in Siral 20 (99.9 %) and Siral 40 (99.9 %) using 26 mg g−1 of enzyme loading. Due to its more hydrophobic nature, Siral 40 was selected as the most suitable support for TLL immobilization using 5 mmol L−1 of sodium phosphate buffer solution, pH 7, and rotational stirring as the optimum condition. The effect of protein concentration on the TLL immobilization was investigated, and the results adjusted well (R2 > 0.99) on the Langmuir isotherm model. The Siral 40 presented a maximum adsorption capacity equal to 169 mgprotein gsupport−1. The heterogeneous biocatalyst (TLL-S40) was applied in biodiesel synthesis, olive oil hydrolysis, p-nitrophenyl-laurate hydrolysis, and ethyl oleate synthesis. The esterification reaction was successfully catalyzed by TLL-S40, leading to a conversion 2.6-fold higher than free TLL at 30 °C. The biocatalyst was reused for three operational cycles with a retention of 34 % of its initial conversion. The results show that Siral 40, a silica-alumina material, can potentially be employed in lipase immobilization for esterification reactions.
{"title":"Immobilization of lipase on zeolite, silica, and silica-aluminas and its use in hydrolysis, esterification, and transesterification reactions","authors":"Kelly C.N.R. Pedro , Gabrielle A.R. da Silva , Mônica A.P. da Silva , Cristiane A. Henriques , Marta A.P. Langone","doi":"10.1016/j.cattod.2024.115141","DOIUrl":"10.1016/j.cattod.2024.115141","url":null,"abstract":"<div><div>Lipases have been immobilized on various supports to catalyze hydrolysis, esterification, and transesterification reactions efficiently. Among a broad range of materials, mesoporous silica has attracted attention thanks to its distinct characteristics and advantages, being widely used for biocatalysis applications. In this work, the lipase from <em>Thermomyces lanuginosus</em> (TLL) was immobilized on six different carriers: two zeolites HZSM-5 (SAR 25 and 280), mesoporous Si-MCM-41, and silica-aluminas Siral 10, 20, and 40. TLL was efficiently immobilized in Siral 20 (99.9 %) and Siral 40 (99.9 %) using 26 mg g<sup>−1</sup> of enzyme loading. Due to its more hydrophobic nature, Siral 40 was selected as the most suitable support for TLL immobilization using 5 mmol L<sup>−1</sup> of sodium phosphate buffer solution, pH 7, and rotational stirring as the optimum condition. The effect of protein concentration on the TLL immobilization was investigated, and the results adjusted well (R<sup>2</sup> > 0.99) on the Langmuir isotherm model. The Siral 40 presented a maximum adsorption capacity equal to 169 mg<sub>protein</sub> g<sub>support</sub><sup>−1</sup>. The heterogeneous biocatalyst (TLL-S40) was applied in biodiesel synthesis, olive oil hydrolysis, <em>p</em>-nitrophenyl-laurate hydrolysis, and ethyl oleate synthesis. The esterification reaction was successfully catalyzed by TLL-S40, leading to a conversion 2.6-fold higher than free TLL at 30 °C. The biocatalyst was reused for three operational cycles with a retention of 34 % of its initial conversion. The results show that Siral 40, a silica-alumina material, can potentially be employed in lipase immobilization for esterification reactions.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115141"},"PeriodicalIF":5.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.cattod.2024.115138
Bhagyesha S. Patil , Alejandra Torres-Velasco , Hashim A. Alzahrani , Skylar Pratt , Juan J. Bravo-Suárez
Tungsten based catalysts supported on silica (zWOX/SiO2) and silica promoted by titania (zWOX/yTiOX/SiO2) were studied for their catalytic activity towards propylene metathesis. The catalysts were prepared by a simple incipient wetness impregnation method using a large pore SiO2 of intermediate surface area (∼50 m2/g). Catalytic activity studies carried out in a fixed-bed reactor (723 K, 101 kPa propylene) indicated that propylene conversion increased with increasing W loading in zWOx/SiO2 catalysts (z = 0.5−6 W/nm2). It was shown that the catalytic activity of a poorly WOX dispersed 6WOX/SiO2 catalyst could be enhanced and maximized by an optimum titania promotion of 2 wt% TiO2 (∼3 Ti/nm2). In situ differential diffuse reflectance (DDR) UV-Vis spectroscopy at reaction conditions showed that TiOX domain size increased with increases in titania loading from isolated TiOX to TiOX clusters to TiO2 nanocrystals. The UV-Vis results also evidenced the existence of highly dispersed isolated WOX species, WOX clusters, and WO3 nanoparticles in the 6WOX/yTiOX/SiO2 (y = 0.5−6 wt% TiO2 or ∼0.7–9 Ti/nm2) catalysts. In situ DDR-UV-Vis, Raman, and mass spectrometry during propylene metathesis, and catalyst oxidation and reduction revealed the reasons for an optimum amount of titania promoter in 6WOX/2TiOX/SiO2. They were the result of a balanced interplay between two factors: (1) enhanced WOx species dispersion due to the presence of a trimeric TiOX cluster and (2) absence of catalyst deactivation (present at high TiO2 loadings) due to the trimeric TiOX cluster poor reactivity towards coke formation.
{"title":"In Situ DDR-UV-Vis and Raman spectroscopic study of titania promoting effect on silica supported tungsten catalysts for enhanced propylene metathesis","authors":"Bhagyesha S. Patil , Alejandra Torres-Velasco , Hashim A. Alzahrani , Skylar Pratt , Juan J. Bravo-Suárez","doi":"10.1016/j.cattod.2024.115138","DOIUrl":"10.1016/j.cattod.2024.115138","url":null,"abstract":"<div><div>Tungsten based catalysts supported on silica (<em>z</em>WO<sub>X</sub>/SiO<sub>2</sub>) and silica promoted by titania (<em>z</em>WO<sub>X</sub>/<em>y</em>TiO<sub>X</sub>/SiO<sub>2</sub>) were studied for their catalytic activity towards propylene metathesis. The catalysts were prepared by a simple incipient wetness impregnation method using a large pore SiO<sub>2</sub> of intermediate surface area (∼50 m<sup>2</sup>/g). Catalytic activity studies carried out in a fixed-bed reactor (723 K, 101 kPa propylene) indicated that propylene conversion increased with increasing W loading in <em>z</em>WOx/SiO<sub>2</sub> catalysts (<em>z</em> = 0.5−6 W/nm<sup>2</sup>). It was shown that the catalytic activity of a poorly WO<sub>X</sub> dispersed 6WO<sub>X</sub>/SiO<sub>2</sub> catalyst could be enhanced and maximized by an optimum titania promotion of 2 wt% TiO<sub>2</sub> (∼3 Ti/nm<sup>2</sup>). In situ differential diffuse reflectance (DDR) UV-Vis spectroscopy at reaction conditions showed that TiO<sub>X</sub> domain size increased with increases in titania loading from isolated TiO<sub>X</sub> to TiO<sub>X</sub> clusters to TiO<sub>2</sub> nanocrystals. The UV-Vis results also evidenced the existence of highly dispersed isolated WO<sub>X</sub> species, WO<sub>X</sub> clusters, and WO<sub>3</sub> nanoparticles in the 6WO<sub>X</sub>/<em>y</em>TiO<sub>X</sub>/SiO<sub>2</sub> (<em>y</em> = 0.5−6 wt% TiO<sub>2</sub> or ∼0.7–9 Ti/nm<sup>2</sup>) catalysts. In situ DDR-UV-Vis, Raman, and mass spectrometry during propylene metathesis, and catalyst oxidation and reduction revealed the reasons for an optimum amount of titania promoter in 6WO<sub>X</sub>/2TiO<sub>X</sub>/SiO<sub>2</sub>. They were the result of a balanced interplay between two factors: (1) enhanced WOx species dispersion due to the presence of a trimeric TiO<sub>X</sub> cluster and (2) absence of catalyst deactivation (present at high TiO<sub>2</sub> loadings) due to the trimeric TiO<sub>X</sub> cluster poor reactivity towards coke formation.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115138"},"PeriodicalIF":5.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142724093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-20DOI: 10.1016/j.cattod.2024.115140
Suelen Martins Stutz Gomes, Samara da Silva Montani, Luz Amparo Palacio, Fatima Maria Zanon Zotin
Three-way automotive catalysts (TWC) are based on noble metals and have two significant limitations: high cost and tendency to form, at low temperatures, nitrous oxide (N2O), which contributes to the greenhouse effect and ozone layer depletion. Thus, it is crucial to study possible substitutes for these components. In this work, catalysts prepared from copper and aluminum hydrotalcite-like materials impregnated with potassium were studied. The formation of the hydrotalcite phase and CuO phase in the catalyst was evidenced by X-ray diffraction (XRD). Temperature-programmed reduction (TPR) results showed that the alkali metal positively influences the reducibility of the catalyst, decreasing its reduction temperature. Temperature-programmed desorption (TPD) analysis revealed electronic promotion, confirming that the presence of potassium facilitates the desorption of molecular nitrogen from the surface and decreases that of N2O. Catalytic tests showed differences in the behavior of the catalysts depending on the pretreatment performed, suggesting that the interaction between potassium and oxidized or reduced copper gives rise to different catalytic sites. The formation of oxygen vacancies in potassium-containing catalysts, identified by XPS, and the increase in the copper metal surface area contributed to explaining the better performance of these catalysts. Also, based on the catalytic tests, more selective catalysts with the addition of potassium (minimizing N2O formation) were obtained, especially at a ratio of 0.025 K/Cu (mol/mol) and after a reducing pretreatment. This catalyst also showed 100 % N2O conversion in the reduction by CO at temperatures close to 100 °C, confirming its excellent performance in nitrous oxide abatement.
{"title":"Performance of copper-aluminum catalysts impregnated with potassium in NO and N2O reduction by CO","authors":"Suelen Martins Stutz Gomes, Samara da Silva Montani, Luz Amparo Palacio, Fatima Maria Zanon Zotin","doi":"10.1016/j.cattod.2024.115140","DOIUrl":"10.1016/j.cattod.2024.115140","url":null,"abstract":"<div><div>Three-way automotive catalysts (TWC) are based on noble metals and have two significant limitations: high cost and tendency to form, at low temperatures, nitrous oxide (N<sub>2</sub>O), which contributes to the greenhouse effect and ozone layer depletion. Thus, it is crucial to study possible substitutes for these components. In this work, catalysts prepared from copper and aluminum hydrotalcite-like materials impregnated with potassium were studied. The formation of the hydrotalcite phase and CuO phase in the catalyst was evidenced by X-ray diffraction (XRD). Temperature-programmed reduction (TPR) results showed that the alkali metal positively influences the reducibility of the catalyst, decreasing its reduction temperature. Temperature-programmed desorption (TPD) analysis revealed electronic promotion, confirming that the presence of potassium facilitates the desorption of molecular nitrogen from the surface and decreases that of N<sub>2</sub>O. Catalytic tests showed differences in the behavior of the catalysts depending on the pretreatment performed, suggesting that the interaction between potassium and oxidized or reduced copper gives rise to different catalytic sites. The formation of oxygen vacancies in potassium-containing catalysts, identified by XPS, and the increase in the copper metal surface area contributed to explaining the better performance of these catalysts. Also, based on the catalytic tests, more selective catalysts with the addition of potassium (minimizing N<sub>2</sub>O formation) were obtained, especially at a ratio of 0.025 K/Cu (mol/mol) and after a reducing pretreatment. This catalyst also showed 100 % N<sub>2</sub>O conversion in the reduction by CO at temperatures close to 100 °C, confirming its excellent performance in nitrous oxide abatement.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"447 ","pages":"Article 115140"},"PeriodicalIF":5.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1016/j.cattod.2024.115139
Marina Aliste , Lixy Olinda León-Morán , Carmen María Martínez-Escudero , Isabel Garrido , Fulgencio Contreras , Pilar Hellín , Pilar Flores , José Fenoll
In recent years, solar photo-Fenton (SPF) processes have gained interest owing to the use of a cost-free and sustainable radiation source and their effectiveness in removing pharmaceuticals, among other Emerging Pollutants (EPs), from wastewater. Especially, when iron complexes are used to work at neutral pH. The stability and biodegradability characteristics make ethylenediamine-N,N-disuccinic acid (EDDS), and nitrilotriacetic acid (NTA) suitable iron complexing agents. In this work, the removal of diclofenac (DCF) and ibuprofen (IBU), two of the most widely used Non-steroidal Anti-Inflammatory Drug (NSAID) for the treatment of pain, at 200 µg L−1 was studied in wastewater using SPF at natural pH, comparing EDDS and NTA as chelating agents for the first time. The main transformation products (TPs) were also monitored. For this purpose, a suitable analytical method using liquid chromatography coupled to triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS) with Electro Spray Ionization negative mode (ESI-) was applied to determine the pharmaceutical EPs and their main TPs in wastewater. Next, they were confirmed by LC-QTOF-HRMS. DCF was degraded 44 % faster with NTA (t1/2 53 min) than with EDDS (t1/2 77 min), although the final removal percentages, including photolysis, were similar (90–93 %). In contrast, IBU removal with EDDS (t1/2 116 min) was twice as fast as with NTA (t1/2 231 min), whereas photolysis was ineffective. Twenty TPs were monitored, of which only three were detected because of the low concentration used in this study: DCF-2C (m/z 258.0326), DCF-6B (m/z 310.0040), and IBU-4 (m/z 221.1181). Their behaviour followed a formation-elimination profile, but only the complete oxidation of DCF-6 was achieved. This work focuses on the kinetic aspects and TPs formed, which are useful for improving knowledge for the development of efficient processes to abate organic pollutants in real aqueous matrices. Therefore, more EPs should be thoroughly studied to determine the efficiency of EDDS and NTA as iron-chelating agents and the necessity of implementing the SPF process in WWTPs.
{"title":"Solar photo-Fenton with Fe3+-EDDS and Fe3+-NTA at neutral pH for removal of ibuprofen, diclofenac and their main transformation products in wastewater","authors":"Marina Aliste , Lixy Olinda León-Morán , Carmen María Martínez-Escudero , Isabel Garrido , Fulgencio Contreras , Pilar Hellín , Pilar Flores , José Fenoll","doi":"10.1016/j.cattod.2024.115139","DOIUrl":"10.1016/j.cattod.2024.115139","url":null,"abstract":"<div><div>In recent years, solar photo-Fenton (SPF) processes have gained interest owing to the use of a cost-free and sustainable radiation source and their effectiveness in removing pharmaceuticals, among other Emerging Pollutants (EPs), from wastewater. Especially, when iron complexes are used to work at neutral pH. The stability and biodegradability characteristics make ethylenediamine-N,N-disuccinic acid (EDDS), and nitrilotriacetic acid (NTA) suitable iron complexing agents. In this work, the removal of diclofenac (DCF) and ibuprofen (IBU), two of the most widely used Non-steroidal Anti-Inflammatory Drug (NSAID) for the treatment of pain, at 200 µg L<sup>−1</sup> was studied in wastewater using SPF at natural pH, comparing EDDS and NTA as chelating agents for the first time. The main transformation products (TPs) were also monitored. For this purpose, a suitable analytical method using liquid chromatography coupled to triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS) with Electro Spray Ionization negative mode (ESI<sup>-</sup>) was applied to determine the pharmaceutical EPs and their main TPs in wastewater. Next, they were confirmed by LC-QTOF-HRMS. DCF was degraded 44 % faster with NTA (t<sub>1/2</sub> 53 min) than with EDDS (t<sub>1/2</sub> 77 min), although the final removal percentages, including photolysis, were similar (90–93 %). In contrast, IBU removal with EDDS (t<sub>1/2</sub> 116 min) was twice as fast as with NTA (t<sub>1/2</sub> 231 min), whereas photolysis was ineffective. Twenty TPs were monitored, of which only three were detected because of the low concentration used in this study: DCF-2C (<em>m/z</em> 258.0326), DCF-6B (<em>m/z</em> 310.0040), and IBU-4 (<em>m/z</em> 221.1181). Their behaviour followed a formation-elimination profile, but only the complete oxidation of DCF-6 was achieved. This work focuses on the kinetic aspects and TPs formed, which are useful for improving knowledge for the development of efficient processes to abate organic pollutants in real aqueous matrices. Therefore, more EPs should be thoroughly studied to determine the efficiency of EDDS and NTA as iron-chelating agents and the necessity of implementing the SPF process in WWTPs.</div></div>","PeriodicalId":264,"journal":{"name":"Catalysis Today","volume":"446 ","pages":"Article 115139"},"PeriodicalIF":5.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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