Here,we demonstrate a photochemical strategy to site-specifically deposit Pd atoms on Au nanoparticles.The high-sensitivity low-energy ion scattering spectra combined with the X-ray photoelectron spectra reveal that t...Here,we demonstrate a photochemical strategy to site-specifically deposit Pd atoms on Au nanoparticles.The high-sensitivity low-energy ion scattering spectra combined with the X-ray photoelectron spectra reveal that the surface electronic structure of Pd can be continuously regulated by tailoring the Pd-to-Au molar ratio and the location of Pd atoms in Au Pd nanoparticles.It is revealed that electron-rich Pd atoms are considerably more active than the net Pd atoms in aerobic alcohol oxidation.Remarkably,the catalyst with the most electron-rich Pd sites(binding energy downshift:1.0 e V)exhibits an extremely high turnover frequency(~500000 h-1 vs 12000 h-1 for that with net Pd atoms)for solvent-free selective oxidation of benzyl alcohol,which is,to the best of our knowledge,the highest value ever reported.Kinetic studies reveal that electron-rich Pd atoms can accelerate the oxidation of benzyl alcohol by facilitating C-H cleavage,as indicated by the significant reduction in the activation energy as compared to net Pd atoms.展开更多
The selective oxidation of alcohol using molecular oxygen as an oxidant and water as a green sol‐vent is of great interest in green chemistry. In this work, we present a systematic study of a Pt/ZnO catalyst for the ...The selective oxidation of alcohol using molecular oxygen as an oxidant and water as a green sol‐vent is of great interest in green chemistry. In this work, we present a systematic study of a Pt/ZnO catalyst for the selective oxidation of benzyl alcohol at room temperature under base‐free aqueous conditions. Experimental observations and density functional theory calculations suggest that ZnO as a support can facilitate the adsorption of benzyl alcohol, which subsequently reacts with the activated oxygen species on the Pt catalyst, producing benzaldehyde. The resulting solid achieves a high conversion（94.1 ± 5.1% in 10 h） of benzyl alcohol and nearly 100% selectivity to benzalde‐hyde with ambient air as the oxidant. In addition, by introducing a small amount of Bi（1.78 wt%） into Pt/ZnO, we can further enhance the activity by 350%.展开更多
Photocatalytic hydrogen production coupled with selective oxidation of organic substrates to produce highvalue-added fine chemicals has drawn increasing attention.Herein,we report a noble metal-free photocatalyst for ...Photocatalytic hydrogen production coupled with selective oxidation of organic substrates to produce highvalue-added fine chemicals has drawn increasing attention.Herein,we report a noble metal-free photocatalyst for the highly efficient and simultaneous generation of hydrogen and the selective oxidation of benzyl alcohol into benzaldehyde over Cd S@Mo S2 heterostructures under visible light.Without the need for a sacrificial agent,Cd S@Mo S2 displayed an excellent hydrogen production rate of 4233μmol g^-1h^-1with0.3 mmol benzyl alcohol,which is approximately 53 times higher than that of bare Cd S nanorods(80μmol g^-1h^-1).The reaction system was highly selective for the oxidation of benzyl alcohol into benzaldehyde.When the amount of benzyl alcohol increased to 1.0 mmol,the hydrogen production reached9033μmol g^-1h^-1.Scanning electron microscopy and transmission electron microscopy images revealed that p-type Mo S2 sheets with a flower-like structure closely adhered to n-type semiconductor Cd S nanorods through the formation of a p-n heterojunction.As a potential Z-scheme photocatalyst,the Cd S@Mo S2 heterostructure effectively produces and separates electron-hole pairs under visible light.Thus,the electrons are used for reduction to generate hydrogen,and the holes oxidize benzyl alcohol into benzaldehyde.Moreover,a mechanism of photogenerated charge transfer and separation was proposed and verified by photoluminescence,electrochemical impedance spectroscopy,photocurrent and Mott-Schottky measurements.The results reveal that the Cd S@Mo S2 heterojunctions have rapid and efficient charge separation and transfer,thereby greatly improving benzyl alcohol dehydrogenation.This work provides insight into the rational design of high-performance Z-scheme photocatalysts and the use of holes and electrons to obtain two valuable chemicals simultaneously.展开更多
文摘Here,we demonstrate a photochemical strategy to site-specifically deposit Pd atoms on Au nanoparticles.The high-sensitivity low-energy ion scattering spectra combined with the X-ray photoelectron spectra reveal that the surface electronic structure of Pd can be continuously regulated by tailoring the Pd-to-Au molar ratio and the location of Pd atoms in Au Pd nanoparticles.It is revealed that electron-rich Pd atoms are considerably more active than the net Pd atoms in aerobic alcohol oxidation.Remarkably,the catalyst with the most electron-rich Pd sites(binding energy downshift:1.0 e V)exhibits an extremely high turnover frequency(~500000 h-1 vs 12000 h-1 for that with net Pd atoms)for solvent-free selective oxidation of benzyl alcohol,which is,to the best of our knowledge,the highest value ever reported.Kinetic studies reveal that electron-rich Pd atoms can accelerate the oxidation of benzyl alcohol by facilitating C-H cleavage,as indicated by the significant reduction in the activation energy as compared to net Pd atoms.
基金supported by the National Natural Science Foundation of China (21703050, 21271153, 21373181)China Postdoctoral Science Foun‐dation (512200‐X91701)Special Research Foundation of Young Teachers in Hangzhou Dianzi University (ZX150204307002/032)~~
文摘The selective oxidation of alcohol using molecular oxygen as an oxidant and water as a green sol‐vent is of great interest in green chemistry. In this work, we present a systematic study of a Pt/ZnO catalyst for the selective oxidation of benzyl alcohol at room temperature under base‐free aqueous conditions. Experimental observations and density functional theory calculations suggest that ZnO as a support can facilitate the adsorption of benzyl alcohol, which subsequently reacts with the activated oxygen species on the Pt catalyst, producing benzaldehyde. The resulting solid achieves a high conversion（94.1 ± 5.1% in 10 h） of benzyl alcohol and nearly 100% selectivity to benzalde‐hyde with ambient air as the oxidant. In addition, by introducing a small amount of Bi（1.78 wt%） into Pt/ZnO, we can further enhance the activity by 350%.
基金supported by the National Key Research and Development Program of China(2017YFA0700102)the National Natural Science Foundation of China(21520102001,21871263 and 21671188)+1 种基金the Key Research Program of Frontier Sciences,CAS(QYZDJ-SSW-SLH045)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)。
文摘Photocatalytic hydrogen production coupled with selective oxidation of organic substrates to produce highvalue-added fine chemicals has drawn increasing attention.Herein,we report a noble metal-free photocatalyst for the highly efficient and simultaneous generation of hydrogen and the selective oxidation of benzyl alcohol into benzaldehyde over Cd S@Mo S2 heterostructures under visible light.Without the need for a sacrificial agent,Cd S@Mo S2 displayed an excellent hydrogen production rate of 4233μmol g^-1h^-1with0.3 mmol benzyl alcohol,which is approximately 53 times higher than that of bare Cd S nanorods(80μmol g^-1h^-1).The reaction system was highly selective for the oxidation of benzyl alcohol into benzaldehyde.When the amount of benzyl alcohol increased to 1.0 mmol,the hydrogen production reached9033μmol g^-1h^-1.Scanning electron microscopy and transmission electron microscopy images revealed that p-type Mo S2 sheets with a flower-like structure closely adhered to n-type semiconductor Cd S nanorods through the formation of a p-n heterojunction.As a potential Z-scheme photocatalyst,the Cd S@Mo S2 heterostructure effectively produces and separates electron-hole pairs under visible light.Thus,the electrons are used for reduction to generate hydrogen,and the holes oxidize benzyl alcohol into benzaldehyde.Moreover,a mechanism of photogenerated charge transfer and separation was proposed and verified by photoluminescence,electrochemical impedance spectroscopy,photocurrent and Mott-Schottky measurements.The results reveal that the Cd S@Mo S2 heterojunctions have rapid and efficient charge separation and transfer,thereby greatly improving benzyl alcohol dehydrogenation.This work provides insight into the rational design of high-performance Z-scheme photocatalysts and the use of holes and electrons to obtain two valuable chemicals simultaneously.
