Photoredox dual reaction of organic synthesis and H2 evolution opens up a novel pathway for collaboratively generating clean fuels and high-quality chemicals,providing a more effective approach of solar energy convers...Photoredox dual reaction of organic synthesis and H2 evolution opens up a novel pathway for collaboratively generating clean fuels and high-quality chemicals,providing a more effective approach of solar energy conversion.Herein,a surface defect-engineered ZnCoS/ZnCdS heterostructure with zinc blende(ZB)/wurtzite(WZ)phase junctions is synthesized for photocatalytic cooperative coupling of benzaldehyde(BAD)and H_(2) production.This surface defect-engineered ZnCoS/ZnCdS heterostructure elaborately integrates the mixed phase junction advantage of ZnCdS semiconductor and the cocatalytic function of ZnCoS possessing Zn(VZn-ZnCoS/ZnCdS)or S vacancies(VS-ZnCoS/ZnCdS).The optimum VS-ZnCoS/ZnCdS simultaneously exhibits a superior H2 production rate of 14.23 mmol h^(-1) g^(-1) accompanied with BAD formation rate of 12.29 mmol h^(-1) g^(-1) under visible-light irradiation,which is approximately two-fold greater than that of pristine ZnCdS.Under simulated sunlight irradiation(AM 1.5),VS-ZnCoS/ZnCdS achieves H2 evolution(27.43 mmol gcat^(-1) h^(-1))with 0.52%of STH efficiency,accompany with 26.31 mmol gcat^(-1) h^(-1) of BAD formation rate.The underlying solar-driven mechanism is elucidated by a series of in-situ characterization and control experiments,which reveals the synergistic effect of interfacial ZB/WZ phase junctions in ZnCdS and S vacancies of ZnCoS on enhancement of the photoredox dual reaction.The VS-ZnCoS/ZnCdS follows a predominant oxygen-centered radical integrating with carbon-centered radical pathways for BAD formation and a simultaneous electron-driven proton reduction for H_(2) production.Interestingly,the nature of surface vacancies not only facilitates the separation of photoinduced charge carriers but also able to selectively adjust the mechanism pathway for BAD production via tuning the oxygen-centered radical and carbon-centered radical formation.展开更多
The copper-cobalt based catalysts were effective for higher alcohol synthesis, the surface state of the catalysts and the nature of the active sites were investigated by using XPS and XAES spectra, and some strong int...The copper-cobalt based catalysts were effective for higher alcohol synthesis, the surface state of the catalysts and the nature of the active sites were investigated by using XPS and XAES spectra, and some strong interactions were also observed, in each of the three cases, (after calcination, after reduction, and during the syngas reaction).展开更多
Alcohol transformation to transportation fuel-range hydrocarbon over HZSM-5 （SIO2/A1203 = 30） catalyst was studied at 360 C and 300 psig. Product distributions and catalyst life were compared between methanol, ethan...Alcohol transformation to transportation fuel-range hydrocarbon over HZSM-5 （SIO2/A1203 = 30） catalyst was studied at 360 C and 300 psig. Product distributions and catalyst life were compared between methanol, ethanol, 1-propanol and 1-butanol as a feed. The catalyst life for 1-propanol and l-butanol was more than double compared with that for methanol and ethanol. For all the alcohols studied, the product distributions （classified to paraffin, olefin, naphthene, aromatic and naphthalene compounds） varied with time on stream （TOS）. At 24 h TOS, liquid product from 1-propanol and 1-butanol transformation primarily contains higher olefin compounds. The alcohol transformation process to higher hydrocarbon involves a complex set of reaction pathways such as dehydration, oligomerization, dehydrocyclization and hydrogenation. Compared with ethylene generated from methanol and ethanol, oligomerization of propylene and butylene has a lower activation energy and can readily take place on weaker acidic sites. On the other hand, dehydrocyclization of the oligomerized products of propylene and butylene to form the cyclic compounds requires the sites with stronger acid strength. Combination of the above mentioned reasons are the primary reasons for olefin rich product generated in the later stage of the time on stream and for the extended catalyst life time for 1-propanol and 1-butanol compared with methanol and ethanol conversion over HZSM-5.展开更多
Syngas conversion to fuels and chemicals is one of the most challenging subjects in the field of C1 chemistry. It is considered as an attractive alternative non-petroleum-based production route. The direct synthesis o...Syngas conversion to fuels and chemicals is one of the most challenging subjects in the field of C1 chemistry. It is considered as an attractive alternative non-petroleum-based production route. The direct synthesis of olefins and alcohols as high value-added chemicals from syngas has drawn particular attention due to its process simplicity, low energy consumption and clean utilization of carbon resource, which conforms to the principles of green carbon science. This review describes the recent advances for the direct production of lower olefins and higher alcohols via syngas conversion. Recent progress in the development of new catalyst systems for enhanced catalytic performance is highlighted. We also give recommendations regarding major challenges for further research in syngas conversion to various chemicals.展开更多
文摘Photoredox dual reaction of organic synthesis and H2 evolution opens up a novel pathway for collaboratively generating clean fuels and high-quality chemicals,providing a more effective approach of solar energy conversion.Herein,a surface defect-engineered ZnCoS/ZnCdS heterostructure with zinc blende(ZB)/wurtzite(WZ)phase junctions is synthesized for photocatalytic cooperative coupling of benzaldehyde(BAD)and H_(2) production.This surface defect-engineered ZnCoS/ZnCdS heterostructure elaborately integrates the mixed phase junction advantage of ZnCdS semiconductor and the cocatalytic function of ZnCoS possessing Zn(VZn-ZnCoS/ZnCdS)or S vacancies(VS-ZnCoS/ZnCdS).The optimum VS-ZnCoS/ZnCdS simultaneously exhibits a superior H2 production rate of 14.23 mmol h^(-1) g^(-1) accompanied with BAD formation rate of 12.29 mmol h^(-1) g^(-1) under visible-light irradiation,which is approximately two-fold greater than that of pristine ZnCdS.Under simulated sunlight irradiation(AM 1.5),VS-ZnCoS/ZnCdS achieves H2 evolution(27.43 mmol gcat^(-1) h^(-1))with 0.52%of STH efficiency,accompany with 26.31 mmol gcat^(-1) h^(-1) of BAD formation rate.The underlying solar-driven mechanism is elucidated by a series of in-situ characterization and control experiments,which reveals the synergistic effect of interfacial ZB/WZ phase junctions in ZnCdS and S vacancies of ZnCoS on enhancement of the photoredox dual reaction.The VS-ZnCoS/ZnCdS follows a predominant oxygen-centered radical integrating with carbon-centered radical pathways for BAD formation and a simultaneous electron-driven proton reduction for H_(2) production.Interestingly,the nature of surface vacancies not only facilitates the separation of photoinduced charge carriers but also able to selectively adjust the mechanism pathway for BAD production via tuning the oxygen-centered radical and carbon-centered radical formation.
文摘The copper-cobalt based catalysts were effective for higher alcohol synthesis, the surface state of the catalysts and the nature of the active sites were investigated by using XPS and XAES spectra, and some strong interactions were also observed, in each of the three cases, (after calcination, after reduction, and during the syngas reaction).
基金the Pacific Northwest National Laboratory's Laboratory Directed Research and Development Funding
文摘Alcohol transformation to transportation fuel-range hydrocarbon over HZSM-5 （SIO2/A1203 = 30） catalyst was studied at 360 C and 300 psig. Product distributions and catalyst life were compared between methanol, ethanol, 1-propanol and 1-butanol as a feed. The catalyst life for 1-propanol and l-butanol was more than double compared with that for methanol and ethanol. For all the alcohols studied, the product distributions （classified to paraffin, olefin, naphthene, aromatic and naphthalene compounds） varied with time on stream （TOS）. At 24 h TOS, liquid product from 1-propanol and 1-butanol transformation primarily contains higher olefin compounds. The alcohol transformation process to higher hydrocarbon involves a complex set of reaction pathways such as dehydration, oligomerization, dehydrocyclization and hydrogenation. Compared with ethylene generated from methanol and ethanol, oligomerization of propylene and butylene has a lower activation energy and can readily take place on weaker acidic sites. On the other hand, dehydrocyclization of the oligomerized products of propylene and butylene to form the cyclic compounds requires the sites with stronger acid strength. Combination of the above mentioned reasons are the primary reasons for olefin rich product generated in the later stage of the time on stream and for the extended catalyst life time for 1-propanol and 1-butanol compared with methanol and ethanol conversion over HZSM-5.
基金supported by the National Natural Science Foundation of China(91545112,21573271,21403278)Shanghai Municipal Science and Technology Commission,China(15DZ1170500)the Chinese Academy of Sciences(QYZDB-SSW-SLH035)
文摘Syngas conversion to fuels and chemicals is one of the most challenging subjects in the field of C1 chemistry. It is considered as an attractive alternative non-petroleum-based production route. The direct synthesis of olefins and alcohols as high value-added chemicals from syngas has drawn particular attention due to its process simplicity, low energy consumption and clean utilization of carbon resource, which conforms to the principles of green carbon science. This review describes the recent advances for the direct production of lower olefins and higher alcohols via syngas conversion. Recent progress in the development of new catalyst systems for enhanced catalytic performance is highlighted. We also give recommendations regarding major challenges for further research in syngas conversion to various chemicals.
