The exploration of non-noble-metal-based photocatalysts with high efficiency and durability toward hydrogen evolution is vitally necessary to meet the challenges of the global energy and environmental crisis.In this w...The exploration of non-noble-metal-based photocatalysts with high efficiency and durability toward hydrogen evolution is vitally necessary to meet the challenges of the global energy and environmental crisis.In this work,we prepared noble-metal-free cobalt phosphide(CoP)as an efficient co-catalyst on La,Cr-codoped SrTiO_(3)(La,Cr:SrTiO_(3))to form a novel photocatalyst with enhanced H_(2)evolution activity.It was evidenced that the introduction of CoP led to a remarkable improvement in the photocatalytic H_(2)evolution activity of La,Cr:SrTiO_(3),and the content of CoP in the composite had an important influence on the photocatalytic activity.The optimized La,Cr:SrTiO_(3)/CoP(4 wt%)composite exhibited a catalytic H_(2)evolution rate of 198.4μmol h^(−1)g^(−1),which was nearly 27 and 15 times higher than that of La,Cr:SrTiO_(3)and CoP,even slightly higher than that of La,Cr:SrTiO_(3)/Pt(0.5 wt%).More importantly,this novel photocatalyst also showed a long-term stability without noticeable activity degradation.Based on the results of UV–vis diffuse reflectance spectroscopy,photoluminescence spectra,photocurrent response,and electrochemical impedance spectra,we ascribed the enhanced H_(2)evolution performance of the La,Cr:SrTiO_(3)/CoP to a synergistic effect including the broadened visible-light response range,accelerated photogenerated charge separation and transfer efficiency.It is believed that our present work throws light on the rational design of novel,high-performance,visible-light-driven hybrid photocatalysts based on non-noble-metal elements.展开更多
Light-driven artificial molecular machines[1,2]are a class of functional small molecules powered by photochemical reactions,broadly divided into molecular motors and molecular photoswitches.Molecular motors[3,4],owing...Light-driven artificial molecular machines[1,2]are a class of functional small molecules powered by photochemical reactions,broadly divided into molecular motors and molecular photoswitches.Molecular motors[3,4],owing to their intrinsic point chirality and dynamic axial chirality,undergo unidirectional rotation about a carbon–carbon double bond when irradiated with light.In nature,biological molecular motors and pumps are ubiquitous:driving vision,intracellular transport,energy conversion,signal transduction,muscle contraction,and locomotion.展开更多
Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects...Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects such as solar sails, among many other important applications. While these efforts benefit from the average value of light’s linear momentum, in this article, we propose exploiting the temporal variation of light’s linear momentum to achieve an oscillatory force of microNewton amplitude and picosecond period. We validate our proposal by analytical calculations and time domain simulations of Maxwell’s equations in the case of a high-index quarter-wave slab irradiated by a terahertz plane electromagnetic wave. In particular, we show that for plane wave terahertz light of electric field amplitude 5000 V/m and frequency 4.8 THz, an oscillatory radiation pressure of amplitude 1.8 × 10<sup>-4</sup> N/m<sup>2</sup> and 0.1 ps period can be achieved.展开更多
Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniqu...Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly（vinyl pyrrolidone） （PVP） and urea （pH = 2） and at 160°C with NaHCO3 （pH = 7 and 8）, respectively. The PVP-derived BiVO4 showed much higher surface areas （5.0-8.4 m2/g） and narrower bandgap energies （2.45-2.49 eV）. The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.展开更多
Light-driven synthetic micro-/nanomotors have attracted considerable attention in recent years due to their unique performances and potential applications. We herein demonstrate the dye-enhanced self-electrophoretic p...Light-driven synthetic micro-/nanomotors have attracted considerable attention in recent years due to their unique performances and potential applications. We herein demonstrate the dye-enhanced self-electrophoretic propulsion of light-driven Ti O_2–Au Janus micromotors in aqueous dye solutions. Compared to the velocities of these micromotors in pure water, 1.7, 1.5, and 1.4 times accelerated motions were observed for them in aqueous solutions of methyl blue(10-5g L^(-1)), cresol red(10^(-4)g L^(-1)),and methyl orange(10^(-4)g L^(-1)), respectively. We determined that the micromotor speed changes depending on thetype of dyes, due to variations in their photodegradation rates. In addition, following the deposition of a paramagnetic Ni layer between the Au and Ti O_2 layers, the micromotor can be precisely navigated under an external magnetic field. Such magnetic micromotors not only facilitate the recycling of micromotors, but also allow reusability in the context of dye detection and degradation.In general, such photocatalytic micro-/nanomotors provide considerable potential for the rapid detection and ‘‘on-thefly'' degradation of dye pollutants in aqueous environments.展开更多
We use a two‐step hydrothermal method to successfully synthesize Sn2Nb2O7nanocrystals with an average size of approximately20nm.The as‐obtained samples are characterized by powder X‐ray diffraction,ultraviolet‐vis...We use a two‐step hydrothermal method to successfully synthesize Sn2Nb2O7nanocrystals with an average size of approximately20nm.The as‐obtained samples are characterized by powder X‐ray diffraction,ultraviolet‐visible diffuse reflectance spectroscopy,Brunauer‐Emmett‐Teller analysis,scanning electron microscopy,and transmission electron microscopy.The photocatalytic activity of the Sn2Nb2O7nanocrystals is evaluated by photocatalytic water splitting under visible light irradiation.The Sn2Nb2O7nanocrystals with a large surface area of52.2m2/g show an enhanced visible‐light‐driven photocatalytic H2production activity,approximately5.5times higher than that of bulk Sn2Nb2O7powder.The higher photocatalytic activity of Sn2Nb2O7nanocrystals is mainly attributed to its relatively high dispersity of nanosized particles and larger specific surface area when compared with the bulk powder.展开更多
Visible light driven tin oxide based photoelectrodes were obtained using SnCl2·2H2O EtOH solution on FTO by dipping and with further heat treatment in air.Photoelectrochemical measurement with three electrodes co...Visible light driven tin oxide based photoelectrodes were obtained using SnCl2·2H2O EtOH solution on FTO by dipping and with further heat treatment in air.Photoelectrochemical measurement with three electrodes configuration under visible light irradiation(λ>420 nm) revealed that this as-prepared photoelectrode showed typical n-type photocurrent effect and the onset potential is negative than that of H+/H2.XRD,UV-Vis spectrum and control experimental results revealed that the visible light driven mechanism for the tin oxide based photoanode maybe ascribed to Sn4+/Sn2+ transformation and the surface oxygen deficiency.展开更多
In this paper,a visible light-responsive Sn^(2+)and N co-doped TiO_(2)photocatalyst was prepared by facile one-pot hydrothermal method.All as-prepared samples were characterized in detail by a series of characterizati...In this paper,a visible light-responsive Sn^(2+)and N co-doped TiO_(2)photocatalyst was prepared by facile one-pot hydrothermal method.All as-prepared samples were characterized in detail by a series of characterization approaches.The results showed that the Sn^(2+)and N elements were co-doped into TiO_(2),while the catalyst still maintains anatase crystal structure and gets irregular little nanocluster in diameter of 9–10 nm with higher specific surface area.The absorption edge of Sn^(2+)and N co-doped TiO_(2)extends to the visible light region.Compared with Sn^(2+)-doped TiO_(2)and N-TiO_(2),the absorption edges have obvious red-shift of about 50 and 70 nm,respectively.The synergistic effect of O 2p-N 2p and O 2p-Sn 5s hybridization to form impurity levels is the main reason for the red-shift.The hydrogen production performance of the Sn^(2+)and N co-doping TiO_(2)(n(N)/n(Ti)=1)catalyst reached the maximum value of 0.37 mmol·h^(-1)·g^(-1)under visible light,which is higher than that of N-doped TiO_(2)and SnTiO_(2)-doped TiO_(2)singly.This result is due to the wider visible light region-responsive ability of Sn^(2+)and N codoped into TiO_(2).Furthermore,mild hydrothermal methods will not make the Sn^(2+)oxidized to Sn^(4+),which make the catalysts still maintain high photocatalytic performance.This work provides a simple and mild method for the preparation of dual-element co-doped TiO_(2)with high crystallinity,excellent performance and broad application prospects.展开更多
Imines are versatile and valuable organic intermediates in the synthesis of fine chemicals,pharmaceuticals and agrochemicals.The direct synthesis of imines through a one-pot procedure via an oxidative process to reduc...Imines are versatile and valuable organic intermediates in the synthesis of fine chemicals,pharmaceuticals and agrochemicals.The direct synthesis of imines through a one-pot procedure via an oxidative process to reduce energy consumption and waste emission has long been pursued.In this study,we prepared a novel visible-light-responsive coordination polymer with a one-dimensional structure for the direct photocatalytic synthesis of imines in the presence of a green and economical oxidant,molecular oxygen.Photocatalytic experiments suggest that the synthesized coordination polymer is not only efficient for the self-coupling of primary amines to generate homo-coupled imines,but also capable of oxidative dehydrogenation of secondary amines with high selectivity to produce hetero-coupled imines.Mechanistic studies have demonstrated that both photocatalytic reactions depend on reactive oxygen species such as singlet oxygen and superoxide radicals in the system,indicating effective electron and energy transfer from a photoexcited coordination polymer to molecular oxygen.This study not only presents a rare example of a visible-light-driven coordination polymer with a low-dimensional structure capable of direct photocatalytic synthesis of imines,but also demonstrates the great potential of photoactive coordination polymers for organic transformations.展开更多
Epoxides are an extremely important class of chemical intermediates in the chemical industry due to the versatility of epoxides in preparing many fine and specialty chemicals.However,designing more active and selectiv...Epoxides are an extremely important class of chemical intermediates in the chemical industry due to the versatility of epoxides in preparing many fine and specialty chemicals.However,designing more active and selective heterogeneous catalysts in epoxidation is still a priority and a challenge.In this work,we demonstrate the synthesis of two new Ag/polyoxometalate-based coordination polymers(Ag_(8)(mttz)_(4)(H_(2)O)[PWVWVI 11O_(4)0]·H_(2)O(1)and Ag_(8)(mttz)4(H_(2)O)[PMo^(V)Mo^(VI)11O_(4)0](2),mttz=5-methylthio-2Htetrazole)that are highly active for the selective oxidation of cis-cyclooctene to epoxycyclooctane under mild conditions(solvent-free,atmospheric pressure,70℃with H_(2)O_(2)as the oxidant under visible light).It is worth noting that compound 1 possesses abundant exposed active edge sites of Ag,resulting in the catalytic performance achieved in the selective oxidation of cis-cyclooctene to epoxycyclooctane being superior to its components(metal,polyoxometalates and ligand)and compound 2 with the conversion/selectivity to epoxycyclooctane of 70.15/99.68%,respectively.The excellent photocatalytic activity of compound 1 should be attributed to the synergy of the components after coordination polymerization and its structure with exposed active edge sites of Ag.展开更多
In the present study,we report a one-step hydrothermal synthesis of visible-light response Cr-doped Sr_(2)Ta_(2)O_(7)nanosheets for photocatalytic hydrogen generation.It is discovered that the Cr ion is successfully d...In the present study,we report a one-step hydrothermal synthesis of visible-light response Cr-doped Sr_(2)Ta_(2)O_(7)nanosheets for photocatalytic hydrogen generation.It is discovered that the Cr ion is successfully doped into the Sr_(2)Ta_(2)O_(7)nanosheet crystal lattice and uniformly distributed without changing the crystal structure and morphology of the Sr_(2)Ta_(2)O_(7)host.展开更多
Solid solutions between LaNbON_(2)and LaMg_(2/3)Nb_(1/3)O_(3),i.e.(LaNbON_(2))_(1−x)(LaMg_(2/3)Nb_(1/3)O_(3))_(x)(0.0≤x≤1.0),have been investigated as photocatalysts for water oxidation into oxygen under visible lig...Solid solutions between LaNbON_(2)and LaMg_(2/3)Nb_(1/3)O_(3),i.e.(LaNbON_(2))_(1−x)(LaMg_(2/3)Nb_(1/3)O_(3))_(x)(0.0≤x≤1.0),have been investigated as photocatalysts for water oxidation into oxygen under visible light illumination(λ≥420 nm).Many important parameters are strongly correlated with solid solution levels,including band gap,nitrogen content,defect concentration,band edge alignments,etc.This offers us a useful tool to steer photocatalytic performance among these solid solutions.Much improved photocatalytic activity is noticed for(LaNbON_(2))_(0.8)(LaMg_(2/3)Nb_(1/3)O_(3))_(0.2)(x=0.2),which gives an AQE as high as 0.53%at 420±20 nm.This useful strategy by forming solid solutions opens new playgrounds full of opportunities for the design and development of efficient photocatalysts for solar energy conversions.展开更多
Photocatalytic splitting of water to produce hydrogen is a potential solution to alleviate environmental pollution and the energy crisis.It is shown here that H_(3)PMo_(12)O_(4)0(PMo_(12))as a co-catalyst with CdS nan...Photocatalytic splitting of water to produce hydrogen is a potential solution to alleviate environmental pollution and the energy crisis.It is shown here that H_(3)PMo_(12)O_(4)0(PMo_(12))as a co-catalyst with CdS nanosheets can form a well-designed composite photocatalyst without the aid of precious metals by microwave synthesis.A small loading of PMo_(12)(1.8%Mo)exhibits highly efficient photocatalytic perform-ance with a maximum hydrogen production of 5.7 mmol h^(−1)g^(−1),nearly six times higher than that of iso-lated CdS nanosheets.The charge transfer process in the photocatalytic system was further confirmed by XPS analysis,where PMo_(12)accelerated the separation of photogenerated carriers,shortened the charge transfer distance and substantially enhanced the photogeneration efficiency and stability of water clea-vage to hydrogen.This combination of polyoxometalates and CdS has promising applications and pro-vides a new way to develop efficient and novel photocatalysts for sustainable solar energy utilization strategies.展开更多
Overall water splitting is considered as one of the most promising strategies to produce renewable energy.Based on low-cost g-C_(3)N_(4),finding an abundant co-catalyst with high-performance photocatalytic activity an...Overall water splitting is considered as one of the most promising strategies to produce renewable energy.Based on low-cost g-C_(3)N_(4),finding an abundant co-catalyst with high-performance photocatalytic activity and good stability is one of the solutions to realize overall water splitting.We designed amorphous NiO modified g-C_(3)N_(4)(NiO/g-C_(3)N_(4))as a photocatalyst,which could achieve efficient visible-light-driven overall water splitting without a sacrificial agent.After adjusting NiO content and calcination temperature,NiO/g-C_(3)N_(4)with 1.26 wt%NiO content obtained at_(3)00°C shows optimal overall water splitting performance.展开更多
For visible-light-driven H_(2)production,rational design of heterojunction photocatalysts might be a feasible strategy to achieve enhanced H_(2)evolution efficiency.Herein,we prepared ZnS/ZnO heterojunctions highly di...For visible-light-driven H_(2)production,rational design of heterojunction photocatalysts might be a feasible strategy to achieve enhanced H_(2)evolution efficiency.Herein,we prepared ZnS/ZnO heterojunctions highly dispersed on porous biomass carbons(ZnS/ZnO@C)through a one-step carbothermal reduction process at elevated temperatures.展开更多
基金supported by the Fundamental Research Funds for the Central Universities of Central South University(2017zzts099)the National Science Foundation of China(11674398)+1 种基金the Hunan Youth Innovation Platformthe Project of Innovation-driven Plan in Central South University(2015CXS004).
文摘The exploration of non-noble-metal-based photocatalysts with high efficiency and durability toward hydrogen evolution is vitally necessary to meet the challenges of the global energy and environmental crisis.In this work,we prepared noble-metal-free cobalt phosphide(CoP)as an efficient co-catalyst on La,Cr-codoped SrTiO_(3)(La,Cr:SrTiO_(3))to form a novel photocatalyst with enhanced H_(2)evolution activity.It was evidenced that the introduction of CoP led to a remarkable improvement in the photocatalytic H_(2)evolution activity of La,Cr:SrTiO_(3),and the content of CoP in the composite had an important influence on the photocatalytic activity.The optimized La,Cr:SrTiO_(3)/CoP(4 wt%)composite exhibited a catalytic H_(2)evolution rate of 198.4μmol h^(−1)g^(−1),which was nearly 27 and 15 times higher than that of La,Cr:SrTiO_(3)and CoP,even slightly higher than that of La,Cr:SrTiO_(3)/Pt(0.5 wt%).More importantly,this novel photocatalyst also showed a long-term stability without noticeable activity degradation.Based on the results of UV–vis diffuse reflectance spectroscopy,photoluminescence spectra,photocurrent response,and electrochemical impedance spectra,we ascribed the enhanced H_(2)evolution performance of the La,Cr:SrTiO_(3)/CoP to a synergistic effect including the broadened visible-light response range,accelerated photogenerated charge separation and transfer efficiency.It is believed that our present work throws light on the rational design of novel,high-performance,visible-light-driven hybrid photocatalysts based on non-noble-metal elements.
文摘Light-driven artificial molecular machines[1,2]are a class of functional small molecules powered by photochemical reactions,broadly divided into molecular motors and molecular photoswitches.Molecular motors[3,4],owing to their intrinsic point chirality and dynamic axial chirality,undergo unidirectional rotation about a carbon–carbon double bond when irradiated with light.In nature,biological molecular motors and pumps are ubiquitous:driving vision,intracellular transport,energy conversion,signal transduction,muscle contraction,and locomotion.
文摘Light carries linear momentum and can therefore exert a radiation force on the objects that it encounters. This established fact enabled optical manipulation of micro/nano-sized objects, as well as macroscopic objects such as solar sails, among many other important applications. While these efforts benefit from the average value of light’s linear momentum, in this article, we propose exploiting the temporal variation of light’s linear momentum to achieve an oscillatory force of microNewton amplitude and picosecond period. We validate our proposal by analytical calculations and time domain simulations of Maxwell’s equations in the case of a high-index quarter-wave slab irradiated by a terahertz plane electromagnetic wave. In particular, we show that for plane wave terahertz light of electric field amplitude 5000 V/m and frequency 4.8 THz, an oscillatory radiation pressure of amplitude 1.8 × 10<sup>-4</sup> N/m<sup>2</sup> and 0.1 ps period can be achieved.
基金supported by the National Natural Science Foundation of China (No. 20973017, 21077007)the Creative Research Foundation of Beijing University of Technology (No. 00500054R4003, 005000543111501)+2 种基金the HiTech Research and Development Program (863)of China (No. 2009AA063201)the Funding Projectfor Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality (No. PHR200907105, PHR201007105,PHR201107104)the Hong Kong Baptist University (FRG2/09-10/023)
文摘Monoclinic BiVO4 with multiple morphologies and/or porous structures were fabricated using the hydrothermal strategy. The materials were characterized by means of the XRD, Raman, TGA/DSC, SEM, XPS, and UV-Vis techniques. The photocatalytic activities of the BiVO4 materials were evaluated for the degradation of Methyl Orange under visible-light irradiation. It is observed that pH value and surfactant exerted a great effect on the morphology and pore structure of the BiVO4 product. Spherical BiVO4 with porous structures, flower-cluster-like BiVO4, and flower-bundle-like BiVO4 were generated hydrothermally at 100°C with poly（vinyl pyrrolidone） （PVP） and urea （pH = 2） and at 160°C with NaHCO3 （pH = 7 and 8）, respectively. The PVP-derived BiVO4 showed much higher surface areas （5.0-8.4 m2/g） and narrower bandgap energies （2.45-2.49 eV）. The best photocatalytic performance of the spherical BiVO4 material with a surface area of 8.4 m2/g was associated with its higher surface area, narrower bandgap energy, higher surface oxygen vacancy density, and unique porous architecture.
文摘Light-driven synthetic micro-/nanomotors have attracted considerable attention in recent years due to their unique performances and potential applications. We herein demonstrate the dye-enhanced self-electrophoretic propulsion of light-driven Ti O_2–Au Janus micromotors in aqueous dye solutions. Compared to the velocities of these micromotors in pure water, 1.7, 1.5, and 1.4 times accelerated motions were observed for them in aqueous solutions of methyl blue(10-5g L^(-1)), cresol red(10^(-4)g L^(-1)),and methyl orange(10^(-4)g L^(-1)), respectively. We determined that the micromotor speed changes depending on thetype of dyes, due to variations in their photodegradation rates. In addition, following the deposition of a paramagnetic Ni layer between the Au and Ti O_2 layers, the micromotor can be precisely navigated under an external magnetic field. Such magnetic micromotors not only facilitate the recycling of micromotors, but also allow reusability in the context of dye detection and degradation.In general, such photocatalytic micro-/nanomotors provide considerable potential for the rapid detection and ‘‘on-thefly'' degradation of dye pollutants in aqueous environments.
文摘We use a two‐step hydrothermal method to successfully synthesize Sn2Nb2O7nanocrystals with an average size of approximately20nm.The as‐obtained samples are characterized by powder X‐ray diffraction,ultraviolet‐visible diffuse reflectance spectroscopy,Brunauer‐Emmett‐Teller analysis,scanning electron microscopy,and transmission electron microscopy.The photocatalytic activity of the Sn2Nb2O7nanocrystals is evaluated by photocatalytic water splitting under visible light irradiation.The Sn2Nb2O7nanocrystals with a large surface area of52.2m2/g show an enhanced visible‐light‐driven photocatalytic H2production activity,approximately5.5times higher than that of bulk Sn2Nb2O7powder.The higher photocatalytic activity of Sn2Nb2O7nanocrystals is mainly attributed to its relatively high dispersity of nanosized particles and larger specific surface area when compared with the bulk powder.
基金supported by the National Natural Science Foundation of China (21103028)the Key Program of Society Development of Guizhou Province (SZ (2008)3008)+1 种基金the Key Program of Science and Technology of Guiyang City ((2008)014)the Cultivating Project of Guizhou Province (024)
文摘Visible light driven tin oxide based photoelectrodes were obtained using SnCl2·2H2O EtOH solution on FTO by dipping and with further heat treatment in air.Photoelectrochemical measurement with three electrodes configuration under visible light irradiation(λ>420 nm) revealed that this as-prepared photoelectrode showed typical n-type photocurrent effect and the onset potential is negative than that of H+/H2.XRD,UV-Vis spectrum and control experimental results revealed that the visible light driven mechanism for the tin oxide based photoanode maybe ascribed to Sn4+/Sn2+ transformation and the surface oxygen deficiency.
基金This study was financially supported by the Natural Science Foundation of China(No.21663009)the National Key R&D Projects of China(No.2018YFC1801706-01)the Science and Technology Supporting Project of Guizhou Province(Nos.[2019]2835 and[2021]480).
文摘In this paper,a visible light-responsive Sn^(2+)and N co-doped TiO_(2)photocatalyst was prepared by facile one-pot hydrothermal method.All as-prepared samples were characterized in detail by a series of characterization approaches.The results showed that the Sn^(2+)and N elements were co-doped into TiO_(2),while the catalyst still maintains anatase crystal structure and gets irregular little nanocluster in diameter of 9–10 nm with higher specific surface area.The absorption edge of Sn^(2+)and N co-doped TiO_(2)extends to the visible light region.Compared with Sn^(2+)-doped TiO_(2)and N-TiO_(2),the absorption edges have obvious red-shift of about 50 and 70 nm,respectively.The synergistic effect of O 2p-N 2p and O 2p-Sn 5s hybridization to form impurity levels is the main reason for the red-shift.The hydrogen production performance of the Sn^(2+)and N co-doping TiO_(2)(n(N)/n(Ti)=1)catalyst reached the maximum value of 0.37 mmol·h^(-1)·g^(-1)under visible light,which is higher than that of N-doped TiO_(2)and SnTiO_(2)-doped TiO_(2)singly.This result is due to the wider visible light region-responsive ability of Sn^(2+)and N codoped into TiO_(2).Furthermore,mild hydrothermal methods will not make the Sn^(2+)oxidized to Sn^(4+),which make the catalysts still maintain high photocatalytic performance.This work provides a simple and mild method for the preparation of dual-element co-doped TiO_(2)with high crystallinity,excellent performance and broad application prospects.
基金supported by the National Natural Science Foundation of China(21473024)the Natural Science Foundation of Jilin Province(20180101290JC)and the Fundamental Research Funds for the Central Universities.
文摘Imines are versatile and valuable organic intermediates in the synthesis of fine chemicals,pharmaceuticals and agrochemicals.The direct synthesis of imines through a one-pot procedure via an oxidative process to reduce energy consumption and waste emission has long been pursued.In this study,we prepared a novel visible-light-responsive coordination polymer with a one-dimensional structure for the direct photocatalytic synthesis of imines in the presence of a green and economical oxidant,molecular oxygen.Photocatalytic experiments suggest that the synthesized coordination polymer is not only efficient for the self-coupling of primary amines to generate homo-coupled imines,but also capable of oxidative dehydrogenation of secondary amines with high selectivity to produce hetero-coupled imines.Mechanistic studies have demonstrated that both photocatalytic reactions depend on reactive oxygen species such as singlet oxygen and superoxide radicals in the system,indicating effective electron and energy transfer from a photoexcited coordination polymer to molecular oxygen.This study not only presents a rare example of a visible-light-driven coordination polymer with a low-dimensional structure capable of direct photocatalytic synthesis of imines,but also demonstrates the great potential of photoactive coordination polymers for organic transformations.
基金supported by the Collaborative Innovation Center of Suzhou Nano Science and Technology,the National Natural Science Foundation of China(51725204,51572179,21471106,21771132,21501126)China Petrochemical Corporation(SINOPEC,417004-1)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20161216)the 111 Project and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Epoxides are an extremely important class of chemical intermediates in the chemical industry due to the versatility of epoxides in preparing many fine and specialty chemicals.However,designing more active and selective heterogeneous catalysts in epoxidation is still a priority and a challenge.In this work,we demonstrate the synthesis of two new Ag/polyoxometalate-based coordination polymers(Ag_(8)(mttz)_(4)(H_(2)O)[PWVWVI 11O_(4)0]·H_(2)O(1)and Ag_(8)(mttz)4(H_(2)O)[PMo^(V)Mo^(VI)11O_(4)0](2),mttz=5-methylthio-2Htetrazole)that are highly active for the selective oxidation of cis-cyclooctene to epoxycyclooctane under mild conditions(solvent-free,atmospheric pressure,70℃with H_(2)O_(2)as the oxidant under visible light).It is worth noting that compound 1 possesses abundant exposed active edge sites of Ag,resulting in the catalytic performance achieved in the selective oxidation of cis-cyclooctene to epoxycyclooctane being superior to its components(metal,polyoxometalates and ligand)and compound 2 with the conversion/selectivity to epoxycyclooctane of 70.15/99.68%,respectively.The excellent photocatalytic activity of compound 1 should be attributed to the synergy of the components after coordination polymerization and its structure with exposed active edge sites of Ag.
基金supported by the National Natural Science Foundation of China(11674398).
文摘In the present study,we report a one-step hydrothermal synthesis of visible-light response Cr-doped Sr_(2)Ta_(2)O_(7)nanosheets for photocatalytic hydrogen generation.It is discovered that the Cr ion is successfully doped into the Sr_(2)Ta_(2)O_(7)nanosheet crystal lattice and uniformly distributed without changing the crystal structure and morphology of the Sr_(2)Ta_(2)O_(7)host.
基金National Natural Science Foundation of China(Grant no.51972233)Natural Science Foundation of Shanghai(Grant no.19ZR1459200)+1 种基金Shanghai Science and Technology Commission(14DZ2261100)Fundamental Research Funds for the Central Universities。
文摘Solid solutions between LaNbON_(2)and LaMg_(2/3)Nb_(1/3)O_(3),i.e.(LaNbON_(2))_(1−x)(LaMg_(2/3)Nb_(1/3)O_(3))_(x)(0.0≤x≤1.0),have been investigated as photocatalysts for water oxidation into oxygen under visible light illumination(λ≥420 nm).Many important parameters are strongly correlated with solid solution levels,including band gap,nitrogen content,defect concentration,band edge alignments,etc.This offers us a useful tool to steer photocatalytic performance among these solid solutions.Much improved photocatalytic activity is noticed for(LaNbON_(2))_(0.8)(LaMg_(2/3)Nb_(1/3)O_(3))_(0.2)(x=0.2),which gives an AQE as high as 0.53%at 420±20 nm.This useful strategy by forming solid solutions opens new playgrounds full of opportunities for the design and development of efficient photocatalysts for solar energy conversions.
基金supported by the National Natural Science Foundation of China(No.92261118,92161103,22071180).
文摘Photocatalytic splitting of water to produce hydrogen is a potential solution to alleviate environmental pollution and the energy crisis.It is shown here that H_(3)PMo_(12)O_(4)0(PMo_(12))as a co-catalyst with CdS nanosheets can form a well-designed composite photocatalyst without the aid of precious metals by microwave synthesis.A small loading of PMo_(12)(1.8%Mo)exhibits highly efficient photocatalytic perform-ance with a maximum hydrogen production of 5.7 mmol h^(−1)g^(−1),nearly six times higher than that of iso-lated CdS nanosheets.The charge transfer process in the photocatalytic system was further confirmed by XPS analysis,where PMo_(12)accelerated the separation of photogenerated carriers,shortened the charge transfer distance and substantially enhanced the photogeneration efficiency and stability of water clea-vage to hydrogen.This combination of polyoxometalates and CdS has promising applications and pro-vides a new way to develop efficient and novel photocatalysts for sustainable solar energy utilization strategies.
基金supported by the Collaborative Innovation Center of Suzhou Nano Science and Technology,the National Natural Science Foundation of China(51725204,51572179,21471106,21771132,and 21501126)the Natural Science Foundation of Jiangsu Province(BK20161216)and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Overall water splitting is considered as one of the most promising strategies to produce renewable energy.Based on low-cost g-C_(3)N_(4),finding an abundant co-catalyst with high-performance photocatalytic activity and good stability is one of the solutions to realize overall water splitting.We designed amorphous NiO modified g-C_(3)N_(4)(NiO/g-C_(3)N_(4))as a photocatalyst,which could achieve efficient visible-light-driven overall water splitting without a sacrificial agent.After adjusting NiO content and calcination temperature,NiO/g-C_(3)N_(4)with 1.26 wt%NiO content obtained at_(3)00°C shows optimal overall water splitting performance.
基金financial support from the NSFC(No.21520102001,21571177 and 51572260)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB20000000)+2 种基金the Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-SLH045)the State Key Laboratory of Structural Chemistry(No.20170032)the International Science and Technology Cooperation and Exchange Project of Fujian Agriculture and Forestry University(No.KXGH17010).J.L.is grateful for receipt of the award of New Century Excellent Talents in Fujian Province University.
文摘For visible-light-driven H_(2)production,rational design of heterojunction photocatalysts might be a feasible strategy to achieve enhanced H_(2)evolution efficiency.Herein,we prepared ZnS/ZnO heterojunctions highly dispersed on porous biomass carbons(ZnS/ZnO@C)through a one-step carbothermal reduction process at elevated temperatures.
