Pub Date : 2025-01-01DOI: 10.1016/S1872-5813(24)60481-0
Dan ZHOU , Hongyue ZHU , Yang ZHAO , Yiming LIU
The nitrogen-coordinated metal single-atom catalysts (M−N−C SACs) with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported. However, most of metal single atoms in these catalysts were buried in the carbon matrix, resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process. Herein, we reported a facile synthesis based on the hard-soft acid-base (HSAB) theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support. Benefiting from the highly accessible Co active sites, the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst, showing a high turnover frequency (TOF) of 0.93 e−·s−1·site−1 at 0.85 V vs. RHE, far exceeding those of some representative SACs with an ultra-high metal content. This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.
{"title":"De novo-design of highly exposed Co−N−C single-atom catalyst for oxygen reduction reaction","authors":"Dan ZHOU , Hongyue ZHU , Yang ZHAO , Yiming LIU","doi":"10.1016/S1872-5813(24)60481-0","DOIUrl":"10.1016/S1872-5813(24)60481-0","url":null,"abstract":"<div><div>The nitrogen-coordinated metal single-atom catalysts (M−N−C SACs) with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported. However, most of metal single atoms in these catalysts were buried in the carbon matrix, resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process. Herein, we reported a facile synthesis based on the hard-soft acid-base (HSAB) theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support. Benefiting from the highly accessible Co active sites, the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst, showing a high turnover frequency (TOF) of 0.93 e<sup>−</sup>·s<sup>−1</sup>·site<sup>−1</sup> at 0.85 V <em>vs.</em> RHE, far exceeding those of some representative SACs with an ultra-high metal content. This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"53 1","pages":"Pages 128-135"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/S1872-5813(24)60484-6
Caiyun WANG , Jiaofei WANG , Yujie ZHANG , Meirong KE , Xudong SONG , Weiguang SU , Yonghui BAI , Peng Lv , Guangsuo YU
Co-pyrolysis of biomass and waste plastics is one of the potential technologies to achieve the resourceful utilization of both, not only to prepare high value-added hydrocarbon-rich bio-oil, but also to achieve clean resourceful utilization of wastes and reduce environmental pollution. However, the products complexity limits its further application of co-pyrolysis technology. In this study, rice straw (RS), an agricultural waste, and polyvinyl chloride plastic (PVC) were used to investigate the individual and co-pyrolysis characteristics of them by thermogravimetric-mass spectrometry (TG-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and the synergistic regulation law of the pyrolysis products by CaO and HZSM-5 composite catalyst. The results show that interactions exist between PVC and RS during the co-pyrolysis process, which promotes the production of aromatic compounds. The relative content of hydrocarbon compounds in tar is as high as 66.78%. The relative content of aromatics reaches 64.17%. Compared with RS pyrolysis, content of oxygenated compounds in the co-pyrolysis tar fraction decreases by 62.05%, which effectively improves oxidative stability of the tar. CaO/HZSM-5 composite catalyst shows better light aromatic selectivity compared with the individual one. The relative content of C4–C10 hydrocarbons in the pyrolysis tar increases by 2.81% and 5.06%, respectively. Under the synergistic effect of CaO/HZSM-5 composite catalyst, relative content of monocyclic aromatic hydrocarbons in the tar is 34.34%, which is larger than the theoretical calculated value of 33.03%. And relative content of PAHs is 28.21%, which is smaller than the theoretical value of 31.22%. In addition, the CaO/HZSM-5 composite catalyst promotes immobilisation of Cl in the form of chlorides such as CaCl2 in the char, which significantly reduces the gas-phase release of elemental Cl.
{"title":"Synergistic effect of CaO/HZSM-5 composite catalyst in regulating co-pyrolysis products of rice straw and PVC","authors":"Caiyun WANG , Jiaofei WANG , Yujie ZHANG , Meirong KE , Xudong SONG , Weiguang SU , Yonghui BAI , Peng Lv , Guangsuo YU","doi":"10.1016/S1872-5813(24)60484-6","DOIUrl":"10.1016/S1872-5813(24)60484-6","url":null,"abstract":"<div><div>Co-pyrolysis of biomass and waste plastics is one of the potential technologies to achieve the resourceful utilization of both, not only to prepare high value-added hydrocarbon-rich bio-oil, but also to achieve clean resourceful utilization of wastes and reduce environmental pollution. However, the products complexity limits its further application of co-pyrolysis technology. In this study, rice straw (RS), an agricultural waste, and polyvinyl chloride plastic (PVC) were used to investigate the individual and co-pyrolysis characteristics of them by thermogravimetric-mass spectrometry (TG-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and the synergistic regulation law of the pyrolysis products by CaO and HZSM-5 composite catalyst. The results show that interactions exist between PVC and RS during the co-pyrolysis process, which promotes the production of aromatic compounds. The relative content of hydrocarbon compounds in tar is as high as 66.78%. The relative content of aromatics reaches 64.17%. Compared with RS pyrolysis, content of oxygenated compounds in the co-pyrolysis tar fraction decreases by 62.05%, which effectively improves oxidative stability of the tar. CaO/HZSM-5 composite catalyst shows better light aromatic selectivity compared with the individual one. The relative content of C<sub>4</sub>–C<sub>10</sub> hydrocarbons in the pyrolysis tar increases by 2.81% and 5.06%, respectively. Under the synergistic effect of CaO/HZSM-5 composite catalyst, relative content of monocyclic aromatic hydrocarbons in the tar is 34.34%, which is larger than the theoretical calculated value of 33.03%. And relative content of PAHs is 28.21%, which is smaller than the theoretical value of 31.22%. In addition, the CaO/HZSM-5 composite catalyst promotes immobilisation of Cl in the form of chlorides such as CaCl<sub>2</sub> in the char, which significantly reduces the gas-phase release of elemental Cl.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"53 1","pages":"Pages 82-94"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/S1872-5813(24)60501-3
Sarfraz MUHAMMAD, Yang LI, He YANG, Lijun JIN, Dekang LI, Haoquan HU
Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents. In this study, a series of red mud (RM)-based sorbents impregnated with sodium halides (NaBr and NaI) are presented to capture elemental mercury (Hg0) from flue gas. The modified RM underwent comprehensive characterization, including analysis of its textural qualities, crystal structure, chemical composition, and thermal properties. The results indicate that the halide impregnation substantially impacts the surface area and pore size of the RM. Hg0 removal performance was evaluated on a fixed-bed reactor in simulated flue gas (consisting of N2, O2, CO2, NO and SO2, etc.) on a modified RM. At an optimal adsorption temperature of 160 °C, NaI-modified sorbent (RMI5) offers a removal efficiency of 98% in a mixture of gas, including O2, NO and HCl. Furthermore, pseudo-second-order model fitting results demonstrate the chemisorption mechanism for the adsorption of Hg0 in kinetic investigations.
{"title":"Removal of elemental mercury from coal combustion flue gas by sodium halides impregnated red mud","authors":"Sarfraz MUHAMMAD, Yang LI, He YANG, Lijun JIN, Dekang LI, Haoquan HU","doi":"10.1016/S1872-5813(24)60501-3","DOIUrl":"10.1016/S1872-5813(24)60501-3","url":null,"abstract":"<div><div>Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents. In this study, a series of red mud (RM)-based sorbents impregnated with sodium halides (NaBr and NaI) are presented to capture elemental mercury (Hg<sup>0</sup>) from flue gas. The modified RM underwent comprehensive characterization, including analysis of its textural qualities, crystal structure, chemical composition, and thermal properties. The results indicate that the halide impregnation substantially impacts the surface area and pore size of the RM. Hg<sup>0</sup> removal performance was evaluated on a fixed-bed reactor in simulated flue gas (consisting of N<sub>2</sub>, O<sub>2</sub>, CO<sub>2</sub>, NO and SO<sub>2</sub>, etc.) on a modified RM. At an optimal adsorption temperature of 160 °C, NaI-modified sorbent (RMI5) offers a removal efficiency of 98% in a mixture of gas, including O<sub>2</sub>, NO and HCl. Furthermore, pseudo-second-order model fitting results demonstrate the chemisorption mechanism for the adsorption of Hg<sup>0</sup> in kinetic investigations.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"53 1","pages":"Pages 53-67"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143104664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/S1872-5813(24)60480-9
Yijing LI, Hanqiong JIA, Wenming HAO, Jinghong MA, Ruifeng LI
Facing the escalating challenge of processing heavier and lower-quality crude oils, the utilization of light cycle oil (LCO) derived from fluid catalytic cracking units is constrained by its high aromatic content. The transformation of LCO into lighter aromatic hydrocarbons through catalytic conversion emerges as a more advantageous and valuable strategy, addressing the surplus of diesel and the scarcity of light aromatics. Consequently, the hydroconversion of 9,10-dihydrophenanthrene (9,10-DHP), serving as a representative molecule of polycyclic aromatic hydrocarbons (PAHs), over metal-free zeolite Y catalysts with varying acidity, has been investigated in a stirred batch reactor. The experiments were conducted at temperatures ranging from 250 to 350 ℃ under a pressure of 4.0 MPa. The study delved into the impact of reaction temperature and the Brønsted acidity of zeolite Y on the reaction pathway. Product analysis revealed the formation of a diverse array of products, including biphenyls, naphthalenes, tetralins, indanes, alkylbenzenes, benzene, and minor alkanes, during the hydrocracking of 9,10-DHP. The reaction pathway for the hydrocracking of 9,10-DHP to monocyclic aromatic hydrocarbons (MAHs) over acidic zeolite Y was proposed to follow two potential routes: one involving hydrogen transfer leading to the formation of phenanthrene and tetrahydrophenanthrene, followed by terminal ring opening; the other characterized by a direct central ring opening. The interplay between these two pathways is contingent upon the reaction temperature and the acidity of the employed zeolite. Promoting central ring opening and suppressing hydrogen transfer can be realized by manipulating the reaction temperature and enhancing the acid density of the zeolite. However, excessive hydrogenation and cracking are observed with further increases in reaction temperature. Additionally, augmenting the strength of acidic sites is beneficial for ring opening and isomerization of hydrogenated aromatics, as well as dealkylation to produce MAHs. The findings underscore a promising approach for the design of PAHs hydrocracking catalysts and reaction techniques.
{"title":"Low temperature hydrocracking of 9,10-dihydrophenanthrene over Brønsted acidic zeolite Y","authors":"Yijing LI, Hanqiong JIA, Wenming HAO, Jinghong MA, Ruifeng LI","doi":"10.1016/S1872-5813(24)60480-9","DOIUrl":"10.1016/S1872-5813(24)60480-9","url":null,"abstract":"<div><div>Facing the escalating challenge of processing heavier and lower-quality crude oils, the utilization of light cycle oil (LCO) derived from fluid catalytic cracking units is constrained by its high aromatic content. The transformation of LCO into lighter aromatic hydrocarbons through catalytic conversion emerges as a more advantageous and valuable strategy, addressing the surplus of diesel and the scarcity of light aromatics. Consequently, the hydroconversion of 9,10-dihydrophenanthrene (9,10-DHP), serving as a representative molecule of polycyclic aromatic hydrocarbons (PAHs), over metal-free zeolite Y catalysts with varying acidity, has been investigated in a stirred batch reactor. The experiments were conducted at temperatures ranging from 250 to 350 ℃ under a pressure of 4.0 MPa. The study delved into the impact of reaction temperature and the Brønsted acidity of zeolite Y on the reaction pathway. Product analysis revealed the formation of a diverse array of products, including biphenyls, naphthalenes, tetralins, indanes, alkylbenzenes, benzene, and minor alkanes, during the hydrocracking of 9,10-DHP. The reaction pathway for the hydrocracking of 9,10-DHP to monocyclic aromatic hydrocarbons (MAHs) over acidic zeolite Y was proposed to follow two potential routes: one involving hydrogen transfer leading to the formation of phenanthrene and tetrahydrophenanthrene, followed by terminal ring opening; the other characterized by a direct central ring opening. The interplay between these two pathways is contingent upon the reaction temperature and the acidity of the employed zeolite. Promoting central ring opening and suppressing hydrogen transfer can be realized by manipulating the reaction temperature and enhancing the acid density of the zeolite. However, excessive hydrogenation and cracking are observed with further increases in reaction temperature. Additionally, augmenting the strength of acidic sites is beneficial for ring opening and isomerization of hydrogenated aromatics, as well as dealkylation to produce MAHs. The findings underscore a promising approach for the design of PAHs hydrocracking catalysts and reaction techniques.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 12","pages":"Pages 1848-1856"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/S1872-5813(24)60479-2
Jiannan LÜ, Yang LI, Lijun JIN, Haoquan HU
Coal pyrolysis integrated with dry reforming of low-carbon alkane (CP-DRA) is an effective way to improve tar yield. Ni/La2O3-ZrO2 with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA. In this study, the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N2 atmosphere (CP-N2) were characterized by using several methods to understand the effect of DRA on coal pyrolysis. The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA. The results showed that the tar from CP-N2 is mainly composed of aliphatic compounds with more Cal, Hal and CH+CH2, and the tar from CP-DRA contains more Car, Har, and CH3, and has lower weight-average molecular weight and more light tar content than CP-N2. A small amount of C2H6 addition in CP-DRA will raise the ratio of Hβ and CH+CH2. Electron paramagnetic resonance (EPR) analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration. The isotope trace experiment showed that alkanes provide ·H, ·CH3, etc. to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.
{"title":"Tar formation characteristic of integrated process of coal pyrolysis with dry reforming of low carbon alkane over Ni/La2O3-ZrO2","authors":"Jiannan LÜ, Yang LI, Lijun JIN, Haoquan HU","doi":"10.1016/S1872-5813(24)60479-2","DOIUrl":"10.1016/S1872-5813(24)60479-2","url":null,"abstract":"<div><div>Coal pyrolysis integrated with dry reforming of low-carbon alkane (CP-DRA) is an effective way to improve tar yield. Ni/La<sub>2</sub>O<sub>3</sub>-ZrO<sub>2</sub> with a La/Zr ratio of 4 was a good catalyst for DRA to inhibit carbon deposition and obtain high tar yield in CP-DRA. In this study, the fraction distribution and component of tars from CP-DRA and coal pyrolysis in N<sub>2</sub> atmosphere (CP-N<sub>2</sub>) were characterized by using several methods to understand the effect of DRA on coal pyrolysis. The isotope trace method was also used to discuss the role of low-carbon alkane in CP-DRA. The results showed that the tar from CP-N<sub>2</sub> is mainly composed of aliphatic compounds with more C<sub>al</sub>, H<sub>al</sub> and CH+CH<sub>2</sub>, and the tar from CP-DRA contains more C<sub>ar</sub>, H<sub>ar,</sub> and CH<sub>3</sub>, and has lower weight-average molecular weight and more light tar content than CP-N<sub>2</sub>. A small amount of C<sub>2</sub>H<sub>6</sub> addition in CP-DRA will raise the ratio of H<sub>β</sub> and CH+CH<sub>2</sub>. Electron paramagnetic resonance (EPR) analysis shows that the tar from CP-DRA has a higher radical concentration while the corresponding char has a lower radical concentration. The isotope trace experiment showed that alkanes provide ·H, ·CH<sub>3</sub>, etc. to stabilize the radicals from coal pyrolysis and result in more alkyl aromatic compounds during CP-DRA.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 12","pages":"Pages 1823-1833"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/S1872-5813(24)60495-0
Jian GONG , Xiujuan GAO , Guozhuang CAO , Xiaqing WANG , Jiacang LIANG , Faen SONG , Junfeng ZHANG , Xiaoxing WANG , Yizhuo HAN , Qingde ZHANG
The synthesis of high-value-added oxygenated chemicals (such as formaldehyde, methyl formate, dimethoxymethane, polyoxymethylene dimethyl ethers, etc.) from methanol/dimethyl ether through an oxidative route boasts advantages of high atom utilization efficiency, distinctive product characteristics, and low carbon emissions, attracting significant attention as a pathway for high-value utilization. However, the oxidation conversion of methanol/dimethyl ether also confronts several challenges, including difficulty in activating C-H bonds at low temperatures, susceptibility to deep oxidation at high temperatures, and difficulty in controlling the chain growth of C-O bonds in larger molecular products. This review will focus on the latest progress in elucidating the mechanisms of the activation and cleavage of C-H bonds in methanol/dimethyl ether molecules at low temperatures and the controllable chain growth of longer C-O bonds by relevant research teams. It aims to outline several representative catalytic reaction mechanisms, thereby providing valuable insights for this field and related research endeavors.
{"title":"Research progress in the oxidative conversion of methanol/dimethyl ether","authors":"Jian GONG , Xiujuan GAO , Guozhuang CAO , Xiaqing WANG , Jiacang LIANG , Faen SONG , Junfeng ZHANG , Xiaoxing WANG , Yizhuo HAN , Qingde ZHANG","doi":"10.1016/S1872-5813(24)60495-0","DOIUrl":"10.1016/S1872-5813(24)60495-0","url":null,"abstract":"<div><div>The synthesis of high-value-added oxygenated chemicals (such as formaldehyde, methyl formate, dimethoxymethane, polyoxymethylene dimethyl ethers, etc.) from methanol/dimethyl ether through an oxidative route boasts advantages of high atom utilization efficiency, distinctive product characteristics, and low carbon emissions, attracting significant attention as a pathway for high-value utilization. However, the oxidation conversion of methanol/dimethyl ether also confronts several challenges, including difficulty in activating C-H bonds at low temperatures, susceptibility to deep oxidation at high temperatures, and difficulty in controlling the chain growth of C-O bonds in larger molecular products. This review will focus on the latest progress in elucidating the mechanisms of the activation and cleavage of C-H bonds in methanol/dimethyl ether molecules at low temperatures and the controllable chain growth of longer C-O bonds by relevant research teams. It aims to outline several representative catalytic reaction mechanisms, thereby providing valuable insights for this field and related research endeavors.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 12","pages":"Pages 1774-1786"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/S1872-5813(24)60472-X
Yao CHEN , Chaoqiu CHEN , Wentao HAO , Wenlong WANG , Kun XIONG , Yong QIN
Platinum is one of the most efficient cocatalysts for photocatalytic reduction of carbon dioxide (CO2) to methane (CH4), but it still suffers from low CO2 reduction rate and low selectivity of CH4. In this study, Pt/TiO2 catalysts with adjustable Pt particle size (0.55-1.80 nm) were prepared by atomic layer deposition (ALD) and used for photocatalytic reduction of CO2 to CH4. The CH4 yield and selectivity of the Pt/TiO2 catalysts showed a volcanic variation trend with the increase of Pt particle size. The 10Pt/TiO2 with Pt particle size of 1.35 nm exhibit the highest methane yield (71.9 μmol/(g·h)). Especially, a high electron-based selectivity of 81.69% for CH4 (product-based selectivity of 90.20%), and 100% for hydrocarbons (CH4, C2H6, and C3H8) are achieved, no H2 formation was detected. The CO-DRIFTS, XPS, CO2-TPD, H2O-TPD, and H2-TPD characterizations suggest that the 10Pt/TiO2 exhibited optimal CO2 adsorption/activation capacity, suitable H2O activation capacity, and higher hydrogen desorption temperature, making the generation rate of active hydrogen species from H2O matches their consumption rate for CO2 hydrogenation. This study opens an avenue for rationally designing highly efficient and selective photocatalysts for photocatalytic CO2 reduction.
{"title":"Size regulation of Pt cocatalysts and its effect on the performance of photocatalytic CO2 transformation to CH4","authors":"Yao CHEN , Chaoqiu CHEN , Wentao HAO , Wenlong WANG , Kun XIONG , Yong QIN","doi":"10.1016/S1872-5813(24)60472-X","DOIUrl":"10.1016/S1872-5813(24)60472-X","url":null,"abstract":"<div><div>Platinum is one of the most efficient cocatalysts for photocatalytic reduction of carbon dioxide (CO<sub>2</sub>) to methane (CH<sub>4</sub>), but it still suffers from low CO<sub>2</sub> reduction rate and low selectivity of CH<sub>4</sub>. In this study, Pt/TiO<sub>2</sub> catalysts with adjustable Pt particle size (0.55-1.80 nm) were prepared by atomic layer deposition (ALD) and used for photocatalytic reduction of CO<sub>2</sub> to CH<sub>4</sub>. The CH<sub>4</sub> yield and selectivity of the Pt/TiO<sub>2</sub> catalysts showed a volcanic variation trend with the increase of Pt particle size. The 10Pt/TiO<sub>2</sub> with Pt particle size of 1.35 nm exhibit the highest methane yield (71.9 μmol/(g·h)). Especially, a high electron-based selectivity of 81.69% for CH<sub>4</sub> (product-based selectivity of 90.20%), and 100% for hydrocarbons (CH<sub>4</sub>, C<sub>2</sub>H<sub>6</sub>, and C<sub>3</sub>H<sub>8</sub>) are achieved, no H<sub>2</sub> formation was detected. The CO-DRIFTS, XPS, CO<sub>2</sub>-TPD, H<sub>2</sub>O-TPD, and H<sub>2</sub>-TPD characterizations suggest that the 10Pt/TiO<sub>2</sub> exhibited optimal CO<sub>2</sub> adsorption/activation capacity, suitable H<sub>2</sub>O activation capacity, and higher hydrogen desorption temperature, making the generation rate of active hydrogen species from H<sub>2</sub>O matches their consumption rate for CO<sub>2</sub> hydrogenation. This study opens an avenue for rationally designing highly efficient and selective photocatalysts for photocatalytic CO<sub>2</sub> reduction.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 12","pages":"Pages 1798-1809"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/S1872-5813(24)60489-5
Zhiqun SHI , Xueqing GONG
Polarons are widely considered to play a crucial role in the charge transport and photocatalytic performance of materials, but the mechanisms of their formation and the underlying driving factors remain a matter of controversy. This study delves into the formation of polarons in different crystalline forms of TiO2 and their connection with the materials’ structure. By employing density functional theory calculations with on-site Coulomb interaction correction (DFT + U), we provide a detailed analysis of the electronic polarization behavior in the anatase and rutile forms of TiO2. We focus on the polarization properties of defect-induced and photoexcited excess electrons on various TiO2 surfaces. The results reveal that the defect electrons can form small polarons on the anatase TiO2(101) surface, while on the rutile TiO2(110) surface, both small and large polarons (hybrid-state polarons) are formed. Photoexcited electrons are capable of forming both small and large polarons on the surfaces of both crystal types. The analysis indicates that the differences in polaron distribution are primarily determined by the intrinsic properties of the crystals; the structural and symmetry differences between anatase and rutile TiO2 lead to the distinct polaron behaviors. Further investigation suggests that the polarization behavior of defect electrons is also related to the arrangement of electron orbitals around the Ti atoms, while the polarization of photoexcited electrons is mainly facilitated by the lattice distortions. These findings elucidate the formation mechanisms of different types of polarons and may contribute to understanding the performance of TiO2 in different fields.
{"title":"A density functional theory study of polarons on different TiO2 surfaces","authors":"Zhiqun SHI , Xueqing GONG","doi":"10.1016/S1872-5813(24)60489-5","DOIUrl":"10.1016/S1872-5813(24)60489-5","url":null,"abstract":"<div><div>Polarons are widely considered to play a crucial role in the charge transport and photocatalytic performance of materials, but the mechanisms of their formation and the underlying driving factors remain a matter of controversy. This study delves into the formation of polarons in different crystalline forms of TiO<sub>2</sub> and their connection with the materials’ structure. By employing density functional theory calculations with on-site Coulomb interaction correction (DFT + U), we provide a detailed analysis of the electronic polarization behavior in the anatase and rutile forms of TiO<sub>2</sub>. We focus on the polarization properties of defect-induced and photoexcited excess electrons on various TiO<sub>2</sub> surfaces. The results reveal that the defect electrons can form small polarons on the anatase TiO<sub>2</sub>(101) surface, while on the rutile TiO<sub>2</sub>(110) surface, both small and large polarons (hybrid-state polarons) are formed. Photoexcited electrons are capable of forming both small and large polarons on the surfaces of both crystal types. The analysis indicates that the differences in polaron distribution are primarily determined by the intrinsic properties of the crystals; the structural and symmetry differences between anatase and rutile TiO<sub>2</sub> lead to the distinct polaron behaviors. Further investigation suggests that the polarization behavior of defect electrons is also related to the arrangement of electron orbitals around the Ti atoms, while the polarization of photoexcited electrons is mainly facilitated by the lattice distortions. These findings elucidate the formation mechanisms of different types of polarons and may contribute to understanding the performance of TiO<sub>2</sub> in different fields.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 12","pages":"Pages 1877-1888"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/S1872-5813(24)60491-3
Yitao HUANG , Minghao GUAN , Jiyuan PEI , Yongyi SONG , Tao WU , Shuandi HOU , Anhui LU
Copper-based catalysts have garnered wide attention in the field of electrocatalytic nitrate reduction for ammonia production due to their low hydrogen precipitation activity and high ammonia selectivity. However, they still face challenges pertaining of poor stability and low activity, which hinder their further application. Herein, we present a Cu2O/Cu heterojunction catalyst supported on nitrogen-doped porous carbon for nitrate reduction. High resolution transmission electron microscopy (HRTEM) and X-ray Diffraction (XRD) results confirm the presence of Cu2O/Cu heterojunctions, which serve as an active phase in catalysis. The nitrogen-doped porous carbon as a carrier not only enhances the catalyst's stability, but also facilitates the exposure and dispersion of active sites. At −1.29 V (vs. RHE), the maximum production rate of ammonia reaches 8.8 mg/(mg·h) with a Faradaic efficiency of 92.8%. This study also elucidates the effect of Cu2O-to-Cu ratio in the heterojunction on catalytic performance, thereby providing valuable insights for designing efficient nitrate reduction catalysts for ammonia production.
{"title":"Cu-based heterojunction catalysts for electrocatalytic nitrate reduction to ammonia","authors":"Yitao HUANG , Minghao GUAN , Jiyuan PEI , Yongyi SONG , Tao WU , Shuandi HOU , Anhui LU","doi":"10.1016/S1872-5813(24)60491-3","DOIUrl":"10.1016/S1872-5813(24)60491-3","url":null,"abstract":"<div><div>Copper-based catalysts have garnered wide attention in the field of electrocatalytic nitrate reduction for ammonia production due to their low hydrogen precipitation activity and high ammonia selectivity. However, they still face challenges pertaining of poor stability and low activity, which hinder their further application. Herein, we present a Cu<sub>2</sub>O/Cu heterojunction catalyst supported on nitrogen-doped porous carbon for nitrate reduction. High resolution transmission electron microscopy (HRTEM) and X-ray Diffraction (XRD) results confirm the presence of Cu<sub>2</sub>O/Cu heterojunctions, which serve as an active phase in catalysis. The nitrogen-doped porous carbon as a carrier not only enhances the catalyst's stability, but also facilitates the exposure and dispersion of active sites. At −1.29 V (<em>vs.</em> RHE), the maximum production rate of ammonia reaches 8.8 mg/(mg·h) with a Faradaic efficiency of 92.8%. This study also elucidates the effect of Cu<sub>2</sub>O-to-Cu ratio in the heterojunction on catalytic performance, thereby providing valuable insights for designing efficient nitrate reduction catalysts for ammonia production.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 12","pages":"Pages 1857-1864"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heterojunction catalysts composed of transition metal sulfides exhibited excellent potentials in electrocatalytic water splitting. Herein, we have designed a FeS/Co3S4 heterojunction catalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline water/seawater solution. Three-dimensional nanoarrays were grown on nickel foam, and the successful synthesis of heterojunction endowed excellent activity to the catalyst. In alkaline water/seawater solution, the low overpotentials (at current density of 10 mA/cm2) of HER were 120.3 and 135.6 mV and the low overpotentials of OER were 212 and 232 mV, respectively. This work provided an effective method for highly-efficiently electrocatalytic splitting of water via fabrication of heterojunction.
{"title":"Hetero-interfaces coupling between FeS and Co3S4 with enhanced electrocatalytic activity in water/seawater splitting","authors":"Zhan ZHAO , Jiao LI , Kelei HUANG , Xiangchao MENG","doi":"10.1016/S1872-5813(24)60490-1","DOIUrl":"10.1016/S1872-5813(24)60490-1","url":null,"abstract":"<div><div>Heterojunction catalysts composed of transition metal sulfides exhibited excellent potentials in electrocatalytic water splitting. Herein, we have designed a FeS/Co<sub>3</sub>S<sub>4</sub> heterojunction catalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline water/seawater solution. Three-dimensional nanoarrays were grown on nickel foam, and the successful synthesis of heterojunction endowed excellent activity to the catalyst. In alkaline water/seawater solution, the low overpotentials (at current density of 10 mA/cm<sup>2</sup>) of HER were 120.3 and 135.6 mV and the low overpotentials of OER were 212 and 232 mV, respectively. This work provided an effective method for highly-efficiently electrocatalytic splitting of water via fabrication of heterojunction.</div></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":"52 12","pages":"Pages 1865-1876"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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