Photocatalytic H_(2)O_(2)production provides a clean and sustainable strategy for artificial photosynthesis.Herein,an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on ...Photocatalytic H_(2)O_(2)production provides a clean and sustainable strategy for artificial photosynthesis.Herein,an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on the surface of resorcinol-formaldehyde(RF)resin spheres.RF spheres played multiple roles:(i)acting as a substrate for the growth of CdS and constructing a core-shell structure with seamless con-tact;(ⅱ)improving visible light absorption of CdS;(ⅲ)forming an S-scheme heterojunction with CdS and promoting the charge separation and transfer.Consequently,under visible light illumination,CdS/RF composite presented remarkably enhanced H_(2)O_(2)production activity.Its H_(2)O_(2)yield in 60 min was 801μmol L^(-1),which was 5.2 and 1.5 times higher than that of RF spheres and CdS hollow spheres,respectively.The charge migration between CdS and RF followed the S-scheme photocatalytic mechanism,which was verified by work function measurement,ex-situ and in-situ irradiated X-ray photoelectron spectroscopy.This work brings a novel insight into designing RF-based inorganic/organic S-scheme heterojunction pho-tocatalysts for efficient H_(2)O_(2)production.展开更多
Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying un...Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying under liquid carbon dioxide as super-critical media and carbonization at 700 ℃ under N2 gas atmosphere. The key of the work is to fabricate carbon aerogels with controllable nano-pore structure, which means extremely high surface area and sharp pore size distribution. Aiming to investigate the effects of preparation conditions on the gelation process, the bulk density, and the physical and chemical structure of the resultant carbon aerogels, the molar ratio of R/C (resorcinol to catalyst) and the amount of distilled water were varied, consequently two different sets of samples, with series of R/C ratio and RF/W (Resorcinol-Formaldehyde to water, or the content of reactant) ratio, were prepared. The result of N2 adsorption/desorption experiment at 77 K shows that the pore sizes decreasing from 11.4 down to 2.2 nm with the increasing of the molar ratio of R/C from 100 to 400, and/or, the pore sizes decreasing from 3.8 down to 1.6 nm with the increasing of reactant content from 0.4 to 0.6.展开更多
Transition metal dichalcogenide(TMD)materials have recently demonstrated exceptional supercapacitor properties after conversion to a metallic phase,which increases the conductivity of the network.However,freestanding,...Transition metal dichalcogenide(TMD)materials have recently demonstrated exceptional supercapacitor properties after conversion to a metallic phase,which increases the conductivity of the network.However,freestanding,exfoliated transition metal dichalcogenide films exhibit surface areas far below their theoretical maximum(1.2%),can fail during electrochemical operation due to poor mechanical properties,and often require pyrophoric chemicals to process.On the other hand,pyrolyzed carbon aerogels exhibit extraordinary specific surface areas for double layer capacitance,high conductivity,and a strong mechanical network of covalent chemical bonds.In this paper,we demonstrate the scalable,rapid nanomanufacturing of TMD(MoS2 and WS2)and carbon aerogel composites,favoring liquid-phase exfoliation to avoid pyrophoric chemicals.The aerogel matrix support enhances conductivity of the composite and the synthesis can complete in 30 min.We find that the addition of transition metal dichalcogenides does not impact the structure of the aerogel,which maintains a high specific surface area up to 620 m^(2) g−1 with peak pore radii of 10 nm.While supercapacitor tests of the aerogels yield capacitances around 80 F g^(−1) at the lowest applied currents,the aerogels loaded with TMD’s exhibit volumetric capacitances up to 127% greater than the unloaded aerogels.In addition,the WS2 aerogels show excellent cycling stability with no capacitance loss over 2000 cycles,as well as markedly better rate capability and lower charge transfer resistance compared to their MoS2-loaded counterparts.We hypothesize that these differences in performance stem from differences in contact resistance and in the favorability of ion adsorption on the chalcogenides.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52173065,51932007,22278324,52073223,22262012 and U1905215)China Postdoctoral Science Foundation(No.2022M710137)the Natural Science Foundation of Hubei Province of China(No.2022CFA001).
文摘Photocatalytic H_(2)O_(2)production provides a clean and sustainable strategy for artificial photosynthesis.Herein,an inorganic/organic composite photocatalyst was fabricated by in-situ growth of CdS nanoparticles on the surface of resorcinol-formaldehyde(RF)resin spheres.RF spheres played multiple roles:(i)acting as a substrate for the growth of CdS and constructing a core-shell structure with seamless con-tact;(ⅱ)improving visible light absorption of CdS;(ⅲ)forming an S-scheme heterojunction with CdS and promoting the charge separation and transfer.Consequently,under visible light illumination,CdS/RF composite presented remarkably enhanced H_(2)O_(2)production activity.Its H_(2)O_(2)yield in 60 min was 801μmol L^(-1),which was 5.2 and 1.5 times higher than that of RF spheres and CdS hollow spheres,respectively.The charge migration between CdS and RF followed the S-scheme photocatalytic mechanism,which was verified by work function measurement,ex-situ and in-situ irradiated X-ray photoelectron spectroscopy.This work brings a novel insight into designing RF-based inorganic/organic S-scheme heterojunction pho-tocatalysts for efficient H_(2)O_(2)production.
基金This project was financially supported by a grant from the NITECH 21st Century COE Program, "World Ceramics Center for Environmental Harmony".
文摘Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying under liquid carbon dioxide as super-critical media and carbonization at 700 ℃ under N2 gas atmosphere. The key of the work is to fabricate carbon aerogels with controllable nano-pore structure, which means extremely high surface area and sharp pore size distribution. Aiming to investigate the effects of preparation conditions on the gelation process, the bulk density, and the physical and chemical structure of the resultant carbon aerogels, the molar ratio of R/C (resorcinol to catalyst) and the amount of distilled water were varied, consequently two different sets of samples, with series of R/C ratio and RF/W (Resorcinol-Formaldehyde to water, or the content of reactant) ratio, were prepared. The result of N2 adsorption/desorption experiment at 77 K shows that the pore sizes decreasing from 11.4 down to 2.2 nm with the increasing of the molar ratio of R/C from 100 to 400, and/or, the pore sizes decreasing from 3.8 down to 1.6 nm with the increasing of reactant content from 0.4 to 0.6.
文摘Transition metal dichalcogenide(TMD)materials have recently demonstrated exceptional supercapacitor properties after conversion to a metallic phase,which increases the conductivity of the network.However,freestanding,exfoliated transition metal dichalcogenide films exhibit surface areas far below their theoretical maximum(1.2%),can fail during electrochemical operation due to poor mechanical properties,and often require pyrophoric chemicals to process.On the other hand,pyrolyzed carbon aerogels exhibit extraordinary specific surface areas for double layer capacitance,high conductivity,and a strong mechanical network of covalent chemical bonds.In this paper,we demonstrate the scalable,rapid nanomanufacturing of TMD(MoS2 and WS2)and carbon aerogel composites,favoring liquid-phase exfoliation to avoid pyrophoric chemicals.The aerogel matrix support enhances conductivity of the composite and the synthesis can complete in 30 min.We find that the addition of transition metal dichalcogenides does not impact the structure of the aerogel,which maintains a high specific surface area up to 620 m^(2) g−1 with peak pore radii of 10 nm.While supercapacitor tests of the aerogels yield capacitances around 80 F g^(−1) at the lowest applied currents,the aerogels loaded with TMD’s exhibit volumetric capacitances up to 127% greater than the unloaded aerogels.In addition,the WS2 aerogels show excellent cycling stability with no capacitance loss over 2000 cycles,as well as markedly better rate capability and lower charge transfer resistance compared to their MoS2-loaded counterparts.We hypothesize that these differences in performance stem from differences in contact resistance and in the favorability of ion adsorption on the chalcogenides.
