Platinum group metal (PGM)-free and Cr-free automotive three-way catalyst (TWC) was examined using two types of base-metal oxides for hydrocarbon preferential oxidation (HC-PROX) and NO reduction by CO in tandem configuration. MnOx-based binary mixed metal oxides (X1Mn2, X = Ba, Ca, Co, Cu, Fe, Mg, Ni, Zn, Zr) were investigated for the design of HC-PROX catalysts. Mg1Mn2 achieved both high propene oxidation activity and low CO oxidation activity, and the catalyst phase was determined as MgMn2O4 having the spinel structure. A tandem TWC composed of MgMn2O4 for HC-PROX and CuCo2O4 for NO-CO reaction showed comparable NO reduction activity and higher oxidation activity of propene and CO compared to Rh/ZrO2 as a benchmark. In-situ FTIR study clarified that the suppression of CO oxidation over MgMn2O4 is caused by strongly adsorbed acetate and formate on the catalyst surface.
{"title":"Design of platinum group metal-free automotive three-way catalyst: MgMn2O4 and CuCo2O4 in tandem layout","authors":"Keisuke Maruichi , Taichi Yamaguchi , Ryosuke Sakai , Kakuya Ueda , Akira Oda , Atsushi Satsuma","doi":"10.1016/j.apcata.2025.120305","DOIUrl":"10.1016/j.apcata.2025.120305","url":null,"abstract":"<div><div>Platinum group metal (PGM)-free and Cr-free automotive three-way catalyst (TWC) was examined using two types of base-metal oxides for hydrocarbon preferential oxidation (HC-PROX) and NO reduction by CO in tandem configuration. MnOx-based binary mixed metal oxides (X1Mn2, X = Ba, Ca, Co, Cu, Fe, Mg, Ni, Zn, Zr) were investigated for the design of HC-PROX catalysts. Mg1Mn2 achieved both high propene oxidation activity and low CO oxidation activity, and the catalyst phase was determined as MgMn<sub>2</sub>O<sub>4</sub> having the spinel structure. A tandem TWC composed of MgMn<sub>2</sub>O<sub>4</sub> for HC-PROX and CuCo<sub>2</sub>O<sub>4</sub> for NO-CO reaction showed comparable NO reduction activity and higher oxidation activity of propene and CO compared to Rh/ZrO<sub>2</sub> as a benchmark. In-situ FTIR study clarified that the suppression of CO oxidation over MgMn<sub>2</sub>O<sub>4</sub> is caused by strongly adsorbed acetate and formate on the catalyst surface.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120305"},"PeriodicalIF":4.7,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855003","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 : 2025-04-21DOI: 10.1016/j.apcata.2025.120303
Qing Hua , Lei Cheng , Wenqiang Qu , Da Wu , Yuehua Li , Zixiang Xu , Xi Cao , Ming Xie , Xiaodong Yan , Chunwei Dong , Dengsong Zhang
The reactive oxygen species (ROS) are of paramount importance for indoor volatile organic compounds removal through photocatalytic technology. However, generating abundant ROS under visible light remains challenging, resulting in the poor photocatalytic performance. Herein, we report a bismuth-modified tungsten oxide (WO3-Bi) photocatalyst with enhanced performance in the visible-light-driven degradation of acetaldehyde, a major indoor air pollutant. Bismuth atoms are atomically doped onto WO3 surface, in which the strong Bi-O adsorption strength facilitates the water and oxygen adsorption to provide abundant ROS. Mechanistic investigations reveal that the photocatalytic oxidation of acetaldehyde involves the C-C breaking of acetic acid into methanol, followed by the complete elimination. These results demonstrate that the surface modification in photocatalyst plays a pivotal role in improving ROS generation and photocatalytic performance, offering a robust and sustainable solution for indoor air purification under visible light.
{"title":"Tailoring reactant adsorption on WO3 via surface bismuth incorporation for enhanced photocatalytic degradation of acetaldehyde","authors":"Qing Hua , Lei Cheng , Wenqiang Qu , Da Wu , Yuehua Li , Zixiang Xu , Xi Cao , Ming Xie , Xiaodong Yan , Chunwei Dong , Dengsong Zhang","doi":"10.1016/j.apcata.2025.120303","DOIUrl":"10.1016/j.apcata.2025.120303","url":null,"abstract":"<div><div>The reactive oxygen species (ROS) are of paramount importance for indoor volatile organic compounds removal through photocatalytic technology. However, generating abundant ROS under visible light remains challenging, resulting in the poor photocatalytic performance. Herein, we report a bismuth-modified tungsten oxide (WO<sub>3</sub>-Bi) photocatalyst with enhanced performance in the visible-light-driven degradation of acetaldehyde, a major indoor air pollutant. Bismuth atoms are atomically doped onto WO<sub>3</sub> surface, in which the strong Bi-O adsorption strength facilitates the water and oxygen adsorption to provide abundant ROS. Mechanistic investigations reveal that the photocatalytic oxidation of acetaldehyde involves the C-C breaking of acetic acid into methanol, followed by the complete elimination. These results demonstrate that the surface modification in photocatalyst plays a pivotal role in improving ROS generation and photocatalytic performance, offering a robust and sustainable solution for indoor air purification under visible light.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120303"},"PeriodicalIF":4.7,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143860496","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 : 2025-04-18DOI: 10.1016/j.apcata.2025.120298
Xinbo Wang , Pengcheng Ma , Cong Yu , Junjie Bian , Xianglong Meng
Oil shale is a promising unconventional energy source whose processed oil products exhibit a H/C ratio comparable to that of crude oil. This study introduced a purely organic acid-base bifunctional porous material, HCP-BBA-S, and conducted a comprehensive investigation of its catalytic performance in the hydrothermal pyrolysis of oil shale under near-critical water conditions. Upon incorporation of the HCP-BBA-S catalyst, shale oil yield increased by 4.61–19.22 %, accompanied by a shift in oil composition towards lower carbon numbers and lower boiling points. Oxygen content in the products decreased significantly, improving oil quality and calorific value. Under optimized conditions, shale oil yield reached 41.85 %, with an H/C atomic ratio of 1.8 and a calorific value of 41.42 MJ/kg. These results highlight HCP-BBA-S as a highly effective catalyst for enhancing both the yield and quality of shale oil, offering a sustainable approach to unconventional energy resource utilization.
{"title":"Acid-base bifunctional porous organic polymers as efficient catalysts for oil shale upgrading","authors":"Xinbo Wang , Pengcheng Ma , Cong Yu , Junjie Bian , Xianglong Meng","doi":"10.1016/j.apcata.2025.120298","DOIUrl":"10.1016/j.apcata.2025.120298","url":null,"abstract":"<div><div>Oil shale is a promising unconventional energy source whose processed oil products exhibit a H/C ratio comparable to that of crude oil. This study introduced a purely organic acid-base bifunctional porous material, HCP-BBA-S, and conducted a comprehensive investigation of its catalytic performance in the hydrothermal pyrolysis of oil shale under near-critical water conditions. Upon incorporation of the HCP-BBA-S catalyst, shale oil yield increased by 4.61–19.22 %, accompanied by a shift in oil composition towards lower carbon numbers and lower boiling points. Oxygen content in the products decreased significantly, improving oil quality and calorific value. Under optimized conditions, shale oil yield reached 41.85 %, with an H/C atomic ratio of 1.8 and a calorific value of 41.42 MJ/kg. These results highlight HCP-BBA-S as a highly effective catalyst for enhancing both the yield and quality of shale oil, offering a sustainable approach to unconventional energy resource utilization.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120298"},"PeriodicalIF":4.7,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847714","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}
The methanol-to-olefins (MTO) process over SAPO-34 catalysts is significantly influenced by surface potential charge, affecting methanol adsorption, intermediate spillover, and coke formation. This study investigates the catalytic performance and mechanistic behavior of SAPO-34 catalysts modified through acidic (SP34-A), basic (SP34-B), and sequential acid-base (SP34-AB) etching, with the unmodified SAPO-34 (SP34-P) serving as a reference. The impact of surface potential charge on catalyst performance was examined using molecular dynamics (MD) simulations, NH3-TPD acidity measurements, and zeta potential analysis. The results reveal that a highly negative surface charge (SP34-A, −67 mV) intensifies methanol adsorption but limits spillover efficiency, promoting formaldehyde accumulation and increasing coke deposition, ultimately reducing catalyst lifetime. In contrast, a positive surface charge (SP34-B, +22 mV) enhances spillover and moderates adsorption strength, reducing coke formation and extending catalyst stability. The sequential acid-base etched catalyst (SP34-AB, +16.9 mV) achieves a well-balanced surface charge, optimizing methanol adsorption, spillover behavior, and diffusion efficiency. This balance minimizes secondary reactions, extends catalyst lifetime (586 min, 1.63 times longer than SP34-P), and improves light olefin selectivity (88.82 %), demonstrating the superior catalytic performance of SP34-AB. Structural and textural analysis further confirms that hierarchical porosity, induced via sequential etching, enhances mass transfer and mitigates diffusion limitations, preventing excessive coke formation. These findings establish surface potential charge as a critical parameter in SAPO-34 catalyst design, highlighting sequential acid-base etching as an effective modification strategy to enhance MTO efficiency and catalyst longevity.
{"title":"Surface potential charge modulation and sequential etching strategies for optimizing SAPO-34 catalysts in the MTO process: Mechanistic insights into catalytic performance","authors":"Hossein Mozafari Khalafbadam, Jafar Towfighi Darian, Masoud Safari Yazd","doi":"10.1016/j.apcata.2025.120290","DOIUrl":"10.1016/j.apcata.2025.120290","url":null,"abstract":"<div><div>The methanol-to-olefins (MTO) process over SAPO-34 catalysts is significantly influenced by surface potential charge, affecting methanol adsorption, intermediate spillover, and coke formation. This study investigates the catalytic performance and mechanistic behavior of SAPO-34 catalysts modified through acidic (SP34-A), basic (SP34-B), and sequential acid-base (SP34-AB) etching, with the unmodified SAPO-34 (SP34-P) serving as a reference. The impact of surface potential charge on catalyst performance was examined using molecular dynamics (MD) simulations, NH<sub>3</sub>-TPD acidity measurements, and zeta potential analysis. The results reveal that a highly negative surface charge (SP34-A, −67 mV) intensifies methanol adsorption but limits spillover efficiency, promoting formaldehyde accumulation and increasing coke deposition, ultimately reducing catalyst lifetime. In contrast, a positive surface charge (SP34-B, +22 mV) enhances spillover and moderates adsorption strength, reducing coke formation and extending catalyst stability. The sequential acid-base etched catalyst (SP34-AB, +16.9 mV) achieves a well-balanced surface charge, optimizing methanol adsorption, spillover behavior, and diffusion efficiency. This balance minimizes secondary reactions, extends catalyst lifetime (586 min, 1.63 times longer than SP34-P), and improves light olefin selectivity (88.82 %), demonstrating the superior catalytic performance of SP34-AB. Structural and textural analysis further confirms that hierarchical porosity, induced via sequential etching, enhances mass transfer and mitigates diffusion limitations, preventing excessive coke formation. These findings establish surface potential charge as a critical parameter in SAPO-34 catalyst design, highlighting sequential acid-base etching as an effective modification strategy to enhance MTO efficiency and catalyst longevity.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120290"},"PeriodicalIF":4.7,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838330","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 : 2025-04-15DOI: 10.1016/j.apcata.2025.120289
Wenru Li , Peiling Zhang , Jianjun Liu , Xin Li , Shaolong Wan , Shuai Wang , Yong Wang , Jingdong Lin
The oxidative conversion of cyclohexane (OCC) to valuable olefins presents an innovative strategy for efficient utilization, overcoming its inherent resistance to traditional cracking methods. This study demonstrates the superior performance of hexagonal boron nitride (h-BN) in OCC, especially mitigating deep oxidation and dehydrogenation to achieve high olefin selectivity. At 550°C, with 32.5 % cyclohexane conversion, cyclohexene selectivity reaches 49.1 % and open-ring alkenes account for 20.1 %. The reaction is driven by gas-phase free radical mechanism, where higher reaction temperature and alkyl-oxygen ratio favor forming open-ring alkenes while maintaining high cyclohexene selectivity. The weak adsorption of olefins on h-BN and the suppression of deep oxidation and dehydrogenation through radical-mediated pathways are crucial for its exceptional performance. This approach effectively minimizes further oxidation and dehydrogenation of radicals and olefins, enhancing olefin selectivity. These findings provide a promising pathway for efficient cyclohexane utilization and advance the understanding of h-BN’s catalytic role in alkane oxidation process.
{"title":"Oxidative conversion of cyclohexane to olefins on hexagonal boron nitride","authors":"Wenru Li , Peiling Zhang , Jianjun Liu , Xin Li , Shaolong Wan , Shuai Wang , Yong Wang , Jingdong Lin","doi":"10.1016/j.apcata.2025.120289","DOIUrl":"10.1016/j.apcata.2025.120289","url":null,"abstract":"<div><div>The oxidative conversion of cyclohexane (OCC) to valuable olefins presents an innovative strategy for efficient utilization, overcoming its inherent resistance to traditional cracking methods. This study demonstrates the superior performance of hexagonal boron nitride (<em>h</em>-BN) in OCC, especially mitigating deep oxidation and dehydrogenation to achieve high olefin selectivity. At 550°C, with 32.5 % cyclohexane conversion, cyclohexene selectivity reaches 49.1 % and open-ring alkenes account for 20.1 %. The reaction is driven by gas-phase free radical mechanism, where higher reaction temperature and alkyl-oxygen ratio favor forming open-ring alkenes while maintaining high cyclohexene selectivity. The weak adsorption of olefins on <em>h</em>-BN and the suppression of deep oxidation and dehydrogenation through radical-mediated pathways are crucial for its exceptional performance. This approach effectively minimizes further oxidation and dehydrogenation of radicals and olefins, enhancing olefin selectivity. These findings provide a promising pathway for efficient cyclohexane utilization and advance the understanding of <em>h</em>-BN’s catalytic role in alkane oxidation process.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120289"},"PeriodicalIF":4.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850068","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 : 2025-04-14DOI: 10.1016/j.apcata.2025.120287
Chaowei Peng, Miao Shui, Haorui Wang, Hongfei Liu
The development of robust catalysts to drive the water oxidation half reaction, i.e. oxygen evolution, is crucial to achieve efficient artificial photosynthesis toward clean solar fuel production. The use of [RuII(bpy)3]2+ as photosensitizer and S2O82- as electron acceptor has been established as a standard photochemical protocol for activity assessment and mechanistic study of synthetic water oxidation catalysts. While a metal-based catalyst is considered indispensable for oxygen evolution therein, we here report that halide (Cl- and Br-) ions alone can straightforwardly drive water oxidation through acting as electron relays (X-→X2→XO-→O2). This may open up new strategies to manage the demanding four-electron transfer kinetics of the photocatalytic oxygen evolution reaction.
{"title":"An alternative photochemical water oxidation pathway driven by halide ions as electron relay","authors":"Chaowei Peng, Miao Shui, Haorui Wang, Hongfei Liu","doi":"10.1016/j.apcata.2025.120287","DOIUrl":"10.1016/j.apcata.2025.120287","url":null,"abstract":"<div><div>The development of robust catalysts to drive the water oxidation half reaction, i.e. oxygen evolution, is crucial to achieve efficient artificial photosynthesis toward clean solar fuel production. The use of [Ru<sup>II</sup>(bpy)<sub>3</sub>]<sup>2+</sup> as photosensitizer and S<sub>2</sub>O<sub>8</sub><sup>2-</sup> as electron acceptor has been established as a standard photochemical protocol for activity assessment and mechanistic study of synthetic water oxidation catalysts. While a metal-based catalyst is considered indispensable for oxygen evolution therein, we here report that halide (Cl<sup>-</sup> and Br<sup>-</sup>) ions alone can straightforwardly drive water oxidation through acting as electron relays (X<sup>-</sup>→X<sub>2</sub>→XO<sup>-</sup>→O<sub>2</sub>). This may open up new strategies to manage the demanding four-electron transfer kinetics of the photocatalytic oxygen evolution reaction.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"699 ","pages":"Article 120287"},"PeriodicalIF":4.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834181","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 : 2025-04-14DOI: 10.1016/j.apcata.2025.120288
Fangchao Wang , Rui Liu , Hongyi Cui , Ali Ramazani , Ali Morsali , Guoying Zhang
The epoxidation of long-chain α-olefins presents a significant challenge in synthetic chemistry, particularly when employing molecular oxygen from air as the sole oxidant under additive-free conditions. In this study, we demonstrate that manganese supported on mesoporous silica (Mn/MSN) effectively catalyzes the aerobic epoxidation of long-chain α-olefins without requiring initiators or sacrificial agents. Mechanistic investigations reveal a synergistic interplay between Mn(II) and Mn(III) species, which facilitates the selective cleavage the peroxo bonds (O–O) in alkyl hydroperoxide intermediates. Strategic incorporation of iron and zirconium into the Mn/MSN framework modulates the manganese oxidation states, enriching the Mn(II)/Mn(III) ratio and achieving a remarkable space-time yield of up to 200 mol epoxide mol⁻¹Mn h⁻¹ . Radical trapping experiments combined with high-resolution mass spectrometry corroborate the formation of allyl carbon-centered and alkoxy radical intermediates during the reaction. This work provides a feasible strategy for long-chain α-olefin aerobic epoxidation without any additives.
{"title":"Optimizing Mn/SiO2 catalyst for additive - free epoxidation of long - chain α -olefins in air","authors":"Fangchao Wang , Rui Liu , Hongyi Cui , Ali Ramazani , Ali Morsali , Guoying Zhang","doi":"10.1016/j.apcata.2025.120288","DOIUrl":"10.1016/j.apcata.2025.120288","url":null,"abstract":"<div><div>The epoxidation of long-chain α-olefins presents a significant challenge in synthetic chemistry, particularly when employing molecular oxygen from air as the sole oxidant under additive-free conditions. In this study, we demonstrate that manganese supported on mesoporous silica (Mn/MSN) effectively catalyzes the aerobic epoxidation of long-chain α-olefins without requiring initiators or sacrificial agents. Mechanistic investigations reveal a synergistic interplay between Mn(II) and Mn(III) species, which facilitates the selective cleavage the peroxo bonds (O–O) in alkyl hydroperoxide intermediates. Strategic incorporation of iron and zirconium into the Mn/MSN framework modulates the manganese oxidation states, enriching the Mn(II)/Mn(III) ratio and achieving a remarkable space-time yield of up to 200 mol <sub>epoxide</sub> mol⁻¹<sub>Mn</sub> h⁻¹ . Radical trapping experiments combined with high-resolution mass spectrometry corroborate the formation of allyl carbon-centered and alkoxy radical intermediates during the reaction. This work provides a feasible strategy for long-chain α-olefin aerobic epoxidation without any additives.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120288"},"PeriodicalIF":4.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838328","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 : 2025-04-14DOI: 10.1016/j.apcata.2025.120286
Yifan Wei , Jingyi Liu , Hanbo Li , Xian Zhang , Ying Zhang , Jiangong Yang , Mingpei Wang , Zhen Liu , Zifeng Yan
The resource utilization of CO2 serves as a feasible method for emission reduction and the establishment of an artificial carbon cycle. This study primarily focuses on the direct synthesis of dimethyl ether (DME) from the hydrogenation of CO2. We have prepared bifunctional catalysts with metal oxides embedded in amorphous silicon-aluminum by an improved Stöber method. By precisely adjusting the Si/Al molar ratio and the CTAB/Si molar ratio in the synthesis precursor solution, structural characteristics and acid properties of the catalyst could be effectively regulated. The results indicated that compared to Cu/ZnO/Al2O3, the catalyst significantly enhanced the selectivity of DME and methanol (MeOH), reduced the selectivity of CO with a moderate conversion rate of CO2. The highest DME selectivity of 37.94 % was achieved at an Si/Al ratio of 8, with the total selectivity for methanol and DME reaching 52.96 %. The addition of cetyltrimethylammonium bromide (CTAB) increased the proportion of Brønsted acid sites and medium-strong acid sites, thereby enhancing methanol dehydration and suppressing the reverse water-gas shift reaction. The optimal selectivity for DME of 43 % was obtained over catalyst prepared with a CTAB/Si molar ratio of 0.1. This study provides a new strategy for the structural design of bifunctional catalysts for CO2 hydrogenation.
{"title":"CuZnAl embedded silicoaluminate catalyst promotion for the hydrogenation of carbon dioxide to dimethyl ether","authors":"Yifan Wei , Jingyi Liu , Hanbo Li , Xian Zhang , Ying Zhang , Jiangong Yang , Mingpei Wang , Zhen Liu , Zifeng Yan","doi":"10.1016/j.apcata.2025.120286","DOIUrl":"10.1016/j.apcata.2025.120286","url":null,"abstract":"<div><div>The resource utilization of CO<sub>2</sub> serves as a feasible method for emission reduction and the establishment of an artificial carbon cycle. This study primarily focuses on the direct synthesis of dimethyl ether (DME) from the hydrogenation of CO<sub>2</sub>. We have prepared bifunctional catalysts with metal oxides embedded in amorphous silicon-aluminum by an improved Stöber method. By precisely adjusting the Si/Al molar ratio and the CTAB/Si molar ratio in the synthesis precursor solution, structural characteristics and acid properties of the catalyst could be effectively regulated. The results indicated that compared to Cu/ZnO/Al<sub>2</sub>O<sub>3</sub>, the catalyst significantly enhanced the selectivity of DME and methanol (MeOH), reduced the selectivity of CO with a moderate conversion rate of CO<sub>2</sub>. The highest DME selectivity of 37.94 % was achieved at an Si/Al ratio of 8, with the total selectivity for methanol and DME reaching 52.96 %. The addition of cetyltrimethylammonium bromide (CTAB) increased the proportion of Brønsted acid sites and medium-strong acid sites, thereby enhancing methanol dehydration and suppressing the reverse water-gas shift reaction. The optimal selectivity for DME of 43 % was obtained over catalyst prepared with a CTAB/Si molar ratio of 0.1. This study provides a new strategy for the structural design of bifunctional catalysts for CO<sub>2</sub> hydrogenation.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120286"},"PeriodicalIF":4.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838329","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 : 2025-04-12DOI: 10.1016/j.apcata.2025.120281
Hanuman G. Kachgunde , Mariyamuthu Mariyaselvakumar , Lakhya Jyoti Konwar , Ankush V. Biradar
Aldehydes are a vital class of fine chemicals, widely utilized as intermediates in drug synthesis, as well as in the production of fragrances and flavors. In industrial settings, aldehydes are predominantly synthesized through hydroformylation reactions. Numerous phosphorus-containing homogeneous and heterogeneous ligands or supports have demonstrated catalytic activity in this process. In this study, we synthesized a rhodium-modified, melamine-paraformaldehyde polymer-based heterogeneous catalyst by condensation followed by a hydrothermal method. The amine groups in the polymer effectively anchored the rhodium, resulting in well-dispersed Rh nanoparticles on the PMF support. The absence of FTIR bands at 2053 and 2143 cm-1 confirmed the dissociation of Rh-complex. The HR-TEM identified the presence of ultrasmall Rh nanoparticles ( Avg. 2.9 nm) on the polymer. The synthesized catalyst demonstrated excellent hydroformylation activity, achieving over 99% styrene conversion with 95% selectivity toward aldehyde products under optimized conditions and maintained performance over four cycles. Rh-PMFH catalyst showed high TON and TOF- 12,302, 2,050 h-1, respectively. In addition, the catalyst showed excellent activity for a broad substrate scope.
{"title":"Melamine paraformaldehyde polymer as an excellent support for hydroformylations of various alkenes","authors":"Hanuman G. Kachgunde , Mariyamuthu Mariyaselvakumar , Lakhya Jyoti Konwar , Ankush V. Biradar","doi":"10.1016/j.apcata.2025.120281","DOIUrl":"10.1016/j.apcata.2025.120281","url":null,"abstract":"<div><div>Aldehydes are a vital class of fine chemicals, widely utilized as intermediates in drug synthesis, as well as in the production of fragrances and flavors. In industrial settings, aldehydes are predominantly synthesized through hydroformylation reactions. Numerous phosphorus-containing homogeneous and heterogeneous ligands or supports have demonstrated catalytic activity in this process. In this study, we synthesized a rhodium-modified, melamine-paraformaldehyde polymer-based heterogeneous catalyst by condensation followed by a hydrothermal method. The amine groups in the polymer effectively anchored the rhodium, resulting in well-dispersed Rh nanoparticles on the PMF support. The absence of FTIR bands at 2053 and 2143<!--> <!-->cm<sup>-1</sup> confirmed the dissociation of Rh-complex. The HR-TEM identified the presence of ultrasmall Rh nanoparticles ( Avg. 2.9<!--> <!-->nm) on the polymer. The synthesized catalyst demonstrated excellent hydroformylation activity, achieving over 99% styrene conversion with 95% selectivity toward aldehyde products under optimized conditions and maintained performance over four cycles. Rh-PMF<sub>H</sub> catalyst showed high TON and TOF- 12,302, 2,050<!--> <!-->h<sup>-1,</sup> respectively. In addition, the catalyst showed excellent activity for a broad substrate scope.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"700 ","pages":"Article 120281"},"PeriodicalIF":4.7,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838332","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 : 2025-04-11DOI: 10.1016/j.apcata.2025.120285
Asma M.O. Aldajani , Mounib Bahri , Elena F. Kozhevnikova , Ivan V. Kozhevnikov
The reverse water gas shift (RWGS) was studied in the presence of catalysts based on Keggin-type polyoxometalates (POMs) such as heteropoly acids H3PMo12O40 and H3PW12O40 and their Co(II) and Ni(II) salts. Under reaction conditions, molybdenum POMs decomposed to form Mo oxide species, which exhibited high activity, selectivity and resistance to deactivation in the RWGS reaction. The catalysts formed from H3PMo12O40 supported on SiO2, TiO2 and γ-Al2O3 produced CO with 100 % selectivity at 31–33 % CO2 conversion at 600 °C and a CO2:H2 molar ratio of 1:1 (cf. 39 % equilibrium conversion). H3PMo12O40/SiO2 was more active than MoO3/SiO2 with the same Mo loading, revealing a phosphorus enhancement effect on the activity of molybdenum species. This effect can be attributed to the influence of phosphate on the dispersion of the Mo oxide active phase. This is supported by STEM, which shows different morphologies of Mo oxide species in H3PMo12O40/SiO2 and MoO3/SiO2 catalysts. Chemical looping and H2-TPR of fresh and spent Mo catalysts show that the reaction occurs through the redox mechanism involving the reduction of Mo(VI) oxide species to Mo(IV) with H2, followed by reoxidation of Mo(IV) with CO2 to form CO (reverse Mars–van Krevelen mechanism). Contrary to the Mo catalysts, tungsten POMs, exhibited no RWGS activity, which can be attributed to their resistance to reduction.
{"title":"Polyoxometalates as catalyst precursors for reverse water gas shift","authors":"Asma M.O. Aldajani , Mounib Bahri , Elena F. Kozhevnikova , Ivan V. Kozhevnikov","doi":"10.1016/j.apcata.2025.120285","DOIUrl":"10.1016/j.apcata.2025.120285","url":null,"abstract":"<div><div>The reverse water gas shift (RWGS) was studied in the presence of catalysts based on Keggin-type polyoxometalates (POMs) such as heteropoly acids H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub> and H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> and their Co(II) and Ni(II) salts. Under reaction conditions, molybdenum POMs decomposed to form Mo oxide species, which exhibited high activity, selectivity and resistance to deactivation in the RWGS reaction. The catalysts formed from H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub> supported on SiO<sub>2</sub>, TiO<sub>2</sub> and γ-Al<sub>2</sub>O<sub>3</sub> produced CO with 100 % selectivity at 31–33 % CO<sub>2</sub> conversion at 600 °C and a CO<sub>2</sub>:H<sub>2</sub> molar ratio of 1:1 (cf. 39 % equilibrium conversion). H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub>/SiO<sub>2</sub> was more active than MoO<sub>3</sub>/SiO<sub>2</sub> with the same Mo loading, revealing a phosphorus enhancement effect on the activity of molybdenum species. This effect can be attributed to the influence of phosphate on the dispersion of the Mo oxide active phase. This is supported by STEM, which shows different morphologies of Mo oxide species in H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub>/SiO<sub>2</sub> and MoO<sub>3</sub>/SiO<sub>2</sub> catalysts. Chemical looping and H<sub>2</sub>-TPR of fresh and spent Mo catalysts show that the reaction occurs through the redox mechanism involving the reduction of Mo(VI) oxide species to Mo(IV) with H<sub>2</sub>, followed by reoxidation of Mo(IV) with CO<sub>2</sub> to form CO (reverse Mars–van Krevelen mechanism). Contrary to the Mo catalysts, tungsten POMs, exhibited no RWGS activity, which can be attributed to their resistance to reduction.</div></div>","PeriodicalId":243,"journal":{"name":"Applied Catalysis A: General","volume":"699 ","pages":"Article 120285"},"PeriodicalIF":4.7,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824524","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}
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