Photocatalytic water splitting is a promising method for hydrogen production.Numerous efficient photocatalysts have been synthesized and utilized.However,photocatalysts without a noble metal as the co-catalyst have be...Photocatalytic water splitting is a promising method for hydrogen production.Numerous efficient photocatalysts have been synthesized and utilized.However,photocatalysts without a noble metal as the co-catalyst have been rarely reported.Herein,a CoP co-catalyst-modified graphitic-C3N4(g-C3N4/CoP)is investigated for photocatalytic water splitting to produce H2.The g-C3N4/CoP composite is synthesized in two steps.The first step is related to thermal decomposition,and the second step involves an electroless plating technique.The photocatalytic activity for hydrogen evolution reactions of g-C3N4 is distinctly increased by loading the appropriate amount of CoP quantum dots(QDs).Among the as-synthesized samples,the optimized one(g-C3N4/CoP-4%)shows exceptional photocatalytic activity as compared with pristine g-C3N4,generating H2 at a rate of 936μmol g^-1 h^-1,even higher than that of g-C3N4 with 4 wt%Pt(665μmol g^-1 h^-1).The UV-visible and optical absorption behavior confirms that g-C3N4 has an absorption edge at 451 nm,but after being composited with CoP,g-C3N4/CoP-4%has an absorption edge at 497 nm.Furthermore,photoluminescence and photocurrent measurements confirm that loading CoP QDs to pristine g-C3N4 not only enhances the charge separation,but also improves the transfer of photogenerated e--h+pairs,thus improving the photocatalytic performance of the catalyst to generate H2.This work demonstrates a feasible strategy for the synthesis of highly efficient metal phosphide-loaded g-C3N4 for hydrogen generation.展开更多
TiO2 nanofibers decorated with Pt and Pd nanoparticles have been synthesized and studied in various photocatalytic processes. Excellent photocatalytic behavior in the decomposition of organic dyes in water, degradatio...TiO2 nanofibers decorated with Pt and Pd nanoparticles have been synthesized and studied in various photocatalytic processes. Excellent photocatalytic behavior in the decomposition of organic dyes in water, degradation of organic stains on the surface of flexible freestanding cellulose/catalyst composite films and in generation of hydrogen from ethanol using both suspended and immobilized catalysts are demonstrated. The performance of the nanofiber-based TiO2 materials is competitive with and in some cases outperforms--their conventional nanoparticle-based counterparts. In all cases, Pd-decorated TiO2 nanoparticles and nanofibers proved to be more efficient than their Pt-based counterparts, which could be explained on the basis of the formation of nano-sized Schottky interfaces at the contacts between TiO2 and metal nanoparticles. The feasibility of forming cellulose/catalyst composites provides a novel way of utilizing photocatalyst materials in large-area coatings and freestanding films.展开更多
We theoretically investigate the high-order-harmonic generation from the H2^＋ molecular ion exposed to the combi- nation of an intense trapezoidal laser and a static field. The results show that the harmonic spectrum...We theoretically investigate the high-order-harmonic generation from the H2^＋ molecular ion exposed to the combi- nation of an intense trapezoidal laser and a static field. The results show that the harmonic spectrum is obviously extended and the short quantum path is selected to contribute to the spectrum, because the corresponding long path is seriously suppressed. Then the combined Coulomb and laser field potentials and the time-dependent electron wave packet distributions are applied to illustrate the physical mechanism of high-order harmonic gen- eration. Finally, by adjusting the intensity of the static field and superposing a properly selected range of the HHG spectrum, a 90-as isolated attosecond pulse is straightforwardly obtained.展开更多
Extended light absorption and dynamic charge separation are vital factors that determine the effectivenessof photocatalysts.In this study,a nonmetallic plasmonic S‐scheme photocatalyst was fabricatedby loading 1D pla...Extended light absorption and dynamic charge separation are vital factors that determine the effectivenessof photocatalysts.In this study,a nonmetallic plasmonic S‐scheme photocatalyst was fabricatedby loading 1D plasmonic W_(18)O_(49)nanowires onto 2D g‐C_(3)N_(4)nanosheets.W_(18)O_(49)nanowiresplay the dual role of a light absorption antenna—that extends light adsorption—and a hot electrondonor—that assists the water reduction reaction in a wider light spectrum range.Moreover,S‐scheme charge transfer resulting from the matching bandgaps of W_(18)O_(49)and g‐C_(3)N_(4)can lead tostrong redox capability and high migration speed of the photoinduced charges.Consequently,in thisstudy,W_(18)O_(49)/g‐C_(3)N_(4)hybrids exhibited higher photocatalytic H2 generation than that of pristineg‐C_(3)N_(4)under light irradiation of 420–550 nm.Furthermore,the H2 production rate of thebest‐performing W_(18)O_(49)/g‐C_(3)N_(4)hybrid was 41.5μmol·g^(−1)·h^(−1)upon exposure to monochromaticlight at 550 nm,whereas pure g‐C_(3)N_(4)showed negligible activity.This study promotes novel andenvironmentally friendly hot‐electron‐assisted S‐scheme photocatalysts for the broad‐spectrumutilization of solar light.展开更多
To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is reporte...To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is reported.The doping effect and the application of graphene as cocatalyst for CdS is studied for photocatalytic H_(2) generation.The most active sample consists of CdS and graphene(CdS-0.15G)exhibits promising photocatalytic activity,producing 3.12 mmol g^-(1) h^-(1) of H_(2) under simulated solar light which is^4.6 times superior than pure CdS nanoparticles giving an apparent quantum efficiency(AQY)of 11.7%.The enhanced photocatalytic activity for H_(2) generation is associated to the narrowing of the bandgap,enhanced light absorption,fast interfacial charge transfer,and higher carrier density(N_(D))in C-doped CdS@G samples.This is achieved by C doping in CdS nanoparticles and the formation of a graphene shell over the C-doped CdS nanoparticles.After stability test,the spent catalysts sample was also characterized to investigate the nanostructure.展开更多
Developing anatase/rutile phase-junction in Ti O_(2)to construct Z-scheme system is quite effective to improve its photoelectrochemical activity.In this work,the anatase/rutile phase-junction Ag/Ti O_(2)nanocomposites...Developing anatase/rutile phase-junction in Ti O_(2)to construct Z-scheme system is quite effective to improve its photoelectrochemical activity.In this work,the anatase/rutile phase-junction Ag/Ti O_(2)nanocomposites are developed as photocathodes for hydrogen production.The optimized Ag/Ti O_(2)nanocomposite achieves a high current density of 1.28 m A cm-2,an incident photon-to-current conversion efficiency(IPCE)of 10.8%,an applied bias photon-to-current efficiency(ABPE)of 0.32 at 390 nm and a charge carriers’lifetime up to 2000 s.Such enhancement on photoelectrochemical activity can be attributed to:(ⅰ)the generated Z-scheme system in the anatase/rutile phase-junction Ag/Ti O_(2)photocathode enhances the separation,diffusion and transformation of electron/hole pairs inside the structure,(ⅱ)Ag nanodots modification in the anatase/rutile phases leading to the tuned band gap with enhanced light absorption and(ⅲ)the formed Schottky barrier after Ag nanodots surface modification provides enough electron traps to avoid the recombination of photogenerated electrons and holes.Our results here suggest that developing phase-junction nanocomposite as photocathode will provide a new vision for their enhanced photoelectrochemical generation of hydrogen.展开更多
Reducing sizes of precious metals and utilization of the mixed small clusters of them as catalysts in reactions are important methods due to more active sites for higher catalytic eciency.Based on rst-principles calcu...Reducing sizes of precious metals and utilization of the mixed small clusters of them as catalysts in reactions are important methods due to more active sites for higher catalytic eciency.Based on rst-principles calculations in this work,we found that the platinumbased clusters of Pt3X(X=Al,Si,Cu)which have the magic number 4 can e ectively catalyze the water decomposition and hydrogen production in just one-step reaction process.The adsorbates of the H2O@Pt3X clusters have strong absorption in the ultraviolet and visible regions with wavelength from 300 nm to 760 nm,indicating the sunlight can be used to drive catalytic hydrolysis for producing clean hydrogen.In addition,the O atom remains on the clusters after hydrolysis and can react with CO to form CO2 in activation barrier of 0.340.58 eV,showing the recycling ability of the products after hydrolysis for eliminating the"poisoning"CO by oxidation.Moreover,the formed CO2 molecule can be detached from the Pt3X clusters at 323 K.Our results provide interesting guidance for practical designing the useful photocatalysts.展开更多
The synthesis of solar-driven chemical value-added products and the degradation of pollutants is a promising approach for sustainable development. However, achieving these works via photocatalysts with efficient charg...The synthesis of solar-driven chemical value-added products and the degradation of pollutants is a promising approach for sustainable development. However, achieving these works via photocatalysts with efficient charge-separation, photo-absorption is challenging. A yolk-shell CuCo_(2)S_(4)@Cu_(2)O Z-scheme nanoreactor (YS-CuCo_(2)S_(4)@Cu_(2) O-NR) with octahedron Cu_(2)O as the core and tubular CuCo2 S4 as the shell, has been synthesized by regulating composition and morphology. YS-CuCo_(2)S_(4)@Cu_(2)O-NR shows superior photocatalytic activities for producing H_(2) O_(2) collaborates by selective oxidation of benzyl alcohol (BA) to high value-added benzaldehyde (BAD)/utilized Fenton-like reaction to degrade multi-pollutants through space-confinement effect, reaching 80% conversion and 99% selectivity of BA, a yield of 12 mM g^(−1) for H_(2)O_(2) and above 90% degradation efficiency for multi-pollutants. A photocatalysis nanoconfinement reactor system is proposed and demonstrated by using yolk-shell to enhance the performance of the chemical reaction. Mechanism studies show that the yolk-shell provides confined space to accelerate redox reaction kinetics;while the inner void promotes light harvesting and keeps yolk Cu_(2) O from deactivation;combined with the Z-scheme charge transfer, engineering Cu^(+) /Cu^(2+) active composition, they are favorable for enhancing the H_(2) O_(2) generation and Fenton-like activity. These findings provide new opportunities for application of yolk-shell Z-scheme metal-oxide-based photocatalysts.展开更多
Renewable energy,such as solar energy,wind energy,and hydraulic energy,mostly belongs to process energy,which is hard to store,while fossil energy belongs to energy-carrier energy,which can achieve long-term storage.C...Renewable energy,such as solar energy,wind energy,and hydraulic energy,mostly belongs to process energy,which is hard to store,while fossil energy belongs to energy-carrier energy,which can achieve long-term storage.Current conversion and utilization technologies for all types of energy mainly focus on power generation.Fossil energy is convenient to store,but its conversion and utilization technologies mainly rely on the combustion of fossil fuels for power and thermal energy generation,emitting huge amounts of pollutants and CO_(2).Power and thermal energy are still process energy which is hard to be stored,and the problem of the low-cost,efficient and long-term storage of energy is difficult to solve,which is the fundamental deficiencies of the current energy production and supply system.H2as an energy-carrier energy enables both clean and efficient use and storage.Therefore,the development of efficient,low-cost,large-scale green H2/power generation is imperative.It is recommended that:(1)new renewable energy units be developed based on integrating H2,thermal energy and power energy poly-generation technology on demand.The already built“sole power generation”renewable energy units should be transformed into H2,thermal energy and power energy poly-generation model,to build a comprehensive energy multi-link supply system that achieves energy storage,transportation and utilization,as well as the full-time,high-efficiency,low-cost conversion and utilization of renewable energy.(2)Developing low-carbon and clean technologies for green H2and power from carbonbased energy sources,achieving efficient energy conversion and full utilization of resources.(3)Building a new industry for high-value conversion and high-quality utilization of fossil fuels to produce the high-value chemical products instead of pollutants which also provides the best solution for large-capacity and long-term energy storage.展开更多
Ag nanoparticles (NPs) were deposited on the surface of g-C3N4 (CN) by an in situ calcination method. NiS was successfully loaded onto the composites by a hydrothermal method. The results showed that the 10 wt%-NiS/1....Ag nanoparticles (NPs) were deposited on the surface of g-C3N4 (CN) by an in situ calcination method. NiS was successfully loaded onto the composites by a hydrothermal method. The results showed that the 10 wt%-NiS/1.0 wt%-Ag/CN composite exhibits excellent photocatalytic H2 generation performance under solar-light irradiation. An H2 production rate of 9.728 mmol·g^-1·h^-1 was achieved, which is 10.82-, 3.45-, and 2.77-times higher than those of pure g-C3N4, 10 wt%-NiS/CN, and 1.0 wt%-Ag/CN composites, respectively. This enhanced photocatalytic H2 generation can be ascribed to the co-decoration of Ag and NiS on the surface of g-C3N4, which efficiently improves light harvesting capacity, photogenerated charge carrier separation, and photocatalytic H2 production kinetics. Thus, this study demonstrates an effective strategy for constructing excellent g-C3N4-related composite photocatalysts for H2 production by using different co-catalysts.展开更多
Photocatalysis is believed to be one of the best methods to realize sustainable H2 production. However, achieving this through heterogeneous photocatalysis still remains a great challenge owing to the absence of activ...Photocatalysis is believed to be one of the best methods to realize sustainable H2 production. However, achieving this through heterogeneous photocatalysis still remains a great challenge owing to the absence of active sites, sluggish surface reaction kinetics, insufficient charge separation, and a high thermodynamic barrier. Therefore, cocatalysts are necessary and of great significance in boosting photocatalytic H2 generation. This review will focus on the promising and appealing low-cost Ni-based H2-generation cocatalysts as the alternatives for the high-cost and low-abundance noble metal cocatalysts. Special emphasis has been placed on the design principle, modification strategies for further enhancing the activity and stability of Ni-based cocatalysts, and identification of the exact active sites and surface reaction mechanisms. Particularly, four types of modification strategies based on increased light harvesting, enhanced charge separation, strengthened interface interaction, and improved electrocatalytic activity have been thoroughly discussed and compared in detail. This review may open a new avenue for designing highly active and durable Ni-based cocatalysts for photocatalytic H2 generation.展开更多
In this paper, nanotubes and nanoribbons of sodium titanate structures were synthesized via hydrothermal methods in alkaline solution. CdS decorated titanate nanotubes and nanoribbons were therefore constructed for ex...In this paper, nanotubes and nanoribbons of sodium titanate structures were synthesized via hydrothermal methods in alkaline solution. CdS decorated titanate nanotubes and nanoribbons were therefore constructed for exploring the performance of hydrogen evolution and synergistic effect of CdS based titanate structures. CdS decorated titanate nanotubes and nanoribbons were characterized by high resolution transmission electron microscopy （HRTEM）, X-ray diffraction （XRD）, UV-vis, Brunauer- Emmett-Teller （BET） and X-ray photoelectron spectroscopy （XPS） measurements. CdS encapsuled in titanate nanotubes （CdS-ETNTs） showed the best capacity of H2 evolution by water splitting and stability than that from the other two structures, i.e., CdS doped titanate nanotubes （CdS-DTNTs） and CdS doped titanate nanoribbons （CdS-DTNRs）, which could be explained by the synergistic effect of decorated CdS with sodium titanate structures and confinement effect of CdS nanoparticles encapsuled inside展开更多
Electrocatalytic synthesis of value-added chemicals is attracting significant research attention owing to its mild reaction conditions, environmental benignity, and potentially scalable application to organic syntheti...Electrocatalytic synthesis of value-added chemicals is attracting significant research attention owing to its mild reaction conditions, environmental benignity, and potentially scalable application to organic synthetic chemistry. Herein, we report the preparation of a single-crystalline NiS2 nanostructure film of N 50 nm thickness grown directly on a carbon fiber doth （NiSJCFC） by a facile vapor-phase hydrothermal （VPH） method. NiSJCFC as an electrocatalyst exhibits activity for both the oxygen evolution reaction （OER） and the hydrogen evolution reaction （HER） in alkaline media. Furthermore, a series of alcohols （2-propanol, 2-butanol, 2-pentanol, and cyclohexanol） were electrocatalytically converted to the corresponding ketones with high selectivity, efficienc and durability using the NiSJCFC electrode in alkaline media. In the presence of 0.45 M alcohol, a remarkably decreased overpotential （- 150 mV, vs. RHE） at the NiS2/CFC anode compared with that for water oxidation to generate O2, i.e., the OER, in alkaline media leads to significantly improved H2 generation. For instance, the H2 generation rate in the presence of 0.45 M 2-propanol is almost 1.2-times of that obtained for pure water splitting, but in a system that employs an applied voltage at least 280 mV lower than that required for water splitting to achieve the same current density （20 mA-crn-2）. Thus, our results demonstrate the applicability of our bifunctional non-precious-metal electrocatalyst for organic synthesis and simultaneous H2 production.展开更多
Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photocatalytic hydrogen generation. However, the effective preparation of...Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photocatalytic hydrogen generation. However, the effective preparation of such photocatalysts has proven challenging.Herein, we report the facile synthesis of a novel noblemetal-free CdS/MoS/CoPi ternary photocatalyst via a visible light-induced synthesis route, in which MoSreduction cocatalysts were precisely grown on the two terminals of CdS nanorods, while CoPi oxidation cocatalysts were preferentially anchored onto the sidewalls of CdS nanorods. Such spatially isolated MoSand CoPi redox cocatalysts endow CdS nanorods with a rapid charge separation, which enhances their hydrogen generation activity. The CdS/MoS/CoPi photocatalyst with optimized CoPi amount achieves the highest Hgeneration rate of 206 μmol/h, which is 21 and 2 times higher than that achieved by using CdS alone(9.7 μmol/h) and CdS/MoS(105 μmol/h), respectively. The present work highlights the effectiveness of the spatial isolation of reduction and oxidation sites for efficient charge separation and thereby provides a promising strategy for the preparation of highly active photocatalysts.展开更多
For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the ‘‘spotlight&q...For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the ‘‘spotlight" and given impetus to the universal's efforts to head for the same direction: stem the worst warming and strive for the renewable energy source. Hydrogen peroxide(H_2O_2) is undoubtedly a good choice,which holds the promise as a clean, efficient, safe and transferrable energy carrier. Octahedral coordination polymer, Cd_3(C_3N_3S_3)_2, was found to be a robust photocatalyst for H_2O_2 generation under visible light irradiation. To further improve the H_2O_2 generation efficiency, adhering the octahedron to reduced graphene(rGO) was applied as the strategy herein. The study shows that by adhering Cd_3(C_3N_3S_3)_2to rGO, the formation of H_2O_2 is 2.5-fold enhanced and its deformation is concurrently suppressed. This work not only demonstrates the effectiveness of adhering Cd_3(C_3N_3S_3)_2polymer to rGO for the improvement of the polymer's photocatalytic performance, but also proposes a general way for the fabrication of graphene/coordination compound hybrids for maximizing their synergy.展开更多
To further understand the effect of structural defects on the electrochemical and photocatalytic properties of TiO2, two synthetic approaches based on hydrothermal synthesis and post-synthetic chemical reduction to ac...To further understand the effect of structural defects on the electrochemical and photocatalytic properties of TiO2, two synthetic approaches based on hydrothermal synthesis and post-synthetic chemical reduction to achieve oxygen defect- implantation were developed herein. These approaches led to the formation of TiO2 nanorods with uniformly distributed defects in either the bulk or on the surface, or the combination of both, in the formed TiO2 nanorods （NRs）. Both approaches utilize unique TiN nanoparticles as the reaction precursor. Electron microscopy and Brunauer-Emmett-Teller （BET） analyses indicate that all the studied samples exhibit similar morphology and similar specific surface areas. X-ray photoelectron spectroscopy （XPS） and electron paramagnetic resonance （EPR） data confirm the existence of oxygen defects （Vo）. The photocatalytic properties of TiO2 with different types of implanted Vo were evaluated based on photocatalytic H2 production. By optimizing the concentration of Vo among the TiO2 NRs subjected to different treatments, significantly higher photocatalytic activities than that of the stoichiometric TiO2 NRs was achieved. The incident photon-to-current efficiency （IPCE） data indicate that the enhanced photocatalytic activity arises mainly from defect-assisted charge separation, which implies that photo-generated electrons or holes can be captured by Vo and suppress the charge recombination process. The results show that the defective TiO2 obtained by combining the two approaches exhibits the greatest photocatalytic activity enhancement amon~ all the samples.展开更多
基金supported by the National Natural Science Foundation of China(51602207)the Doctoral Scientific Research Foundation of Liaoning Province(20170520011)+3 种基金the Program for Liaoning Excellent Talents in Universities(LR2017074)the Open Project Program of the State Key Laboratory of Photocatalysis on Energy and Environment(SKLPEE-201810)Fuzhou University,the Scientific Research Project of the Educational Department of Liaoning Province(LQN201712)Shenyang Excellent Talents in Universities(RC180211)~~
文摘Photocatalytic water splitting is a promising method for hydrogen production.Numerous efficient photocatalysts have been synthesized and utilized.However,photocatalysts without a noble metal as the co-catalyst have been rarely reported.Herein,a CoP co-catalyst-modified graphitic-C3N4(g-C3N4/CoP)is investigated for photocatalytic water splitting to produce H2.The g-C3N4/CoP composite is synthesized in two steps.The first step is related to thermal decomposition,and the second step involves an electroless plating technique.The photocatalytic activity for hydrogen evolution reactions of g-C3N4 is distinctly increased by loading the appropriate amount of CoP quantum dots(QDs).Among the as-synthesized samples,the optimized one(g-C3N4/CoP-4%)shows exceptional photocatalytic activity as compared with pristine g-C3N4,generating H2 at a rate of 936μmol g^-1 h^-1,even higher than that of g-C3N4 with 4 wt%Pt(665μmol g^-1 h^-1).The UV-visible and optical absorption behavior confirms that g-C3N4 has an absorption edge at 451 nm,but after being composited with CoP,g-C3N4/CoP-4%has an absorption edge at 497 nm.Furthermore,photoluminescence and photocurrent measurements confirm that loading CoP QDs to pristine g-C3N4 not only enhances the charge separation,but also improves the transfer of photogenerated e--h+pairs,thus improving the photocatalytic performance of the catalyst to generate H2.This work demonstrates a feasible strategy for the synthesis of highly efficient metal phosphide-loaded g-C3N4 for hydrogen generation.
文摘TiO2 nanofibers decorated with Pt and Pd nanoparticles have been synthesized and studied in various photocatalytic processes. Excellent photocatalytic behavior in the decomposition of organic dyes in water, degradation of organic stains on the surface of flexible freestanding cellulose/catalyst composite films and in generation of hydrogen from ethanol using both suspended and immobilized catalysts are demonstrated. The performance of the nanofiber-based TiO2 materials is competitive with and in some cases outperforms--their conventional nanoparticle-based counterparts. In all cases, Pd-decorated TiO2 nanoparticles and nanofibers proved to be more efficient than their Pt-based counterparts, which could be explained on the basis of the formation of nano-sized Schottky interfaces at the contacts between TiO2 and metal nanoparticles. The feasibility of forming cellulose/catalyst composites provides a novel way of utilizing photocatalyst materials in large-area coatings and freestanding films.
基金Supported by the National Natural Science Foundation of China under Grant No 11404204the Key Project of the Ministry of Education of China under Grant No 211025+1 种基金the Research Fund for the Doctoral Program of Higher Education of China under Grant No 20111404120004the Natural Science Foundation for Young Scientists of Shanxi Province of China under Grant No2009021005
文摘We theoretically investigate the high-order-harmonic generation from the H2^＋ molecular ion exposed to the combi- nation of an intense trapezoidal laser and a static field. The results show that the harmonic spectrum is obviously extended and the short quantum path is selected to contribute to the spectrum, because the corresponding long path is seriously suppressed. Then the combined Coulomb and laser field potentials and the time-dependent electron wave packet distributions are applied to illustrate the physical mechanism of high-order harmonic gen- eration. Finally, by adjusting the intensity of the static field and superposing a properly selected range of the HHG spectrum, a 90-as isolated attosecond pulse is straightforwardly obtained.
文摘Extended light absorption and dynamic charge separation are vital factors that determine the effectivenessof photocatalysts.In this study,a nonmetallic plasmonic S‐scheme photocatalyst was fabricatedby loading 1D plasmonic W_(18)O_(49)nanowires onto 2D g‐C_(3)N_(4)nanosheets.W_(18)O_(49)nanowiresplay the dual role of a light absorption antenna—that extends light adsorption—and a hot electrondonor—that assists the water reduction reaction in a wider light spectrum range.Moreover,S‐scheme charge transfer resulting from the matching bandgaps of W_(18)O_(49)and g‐C_(3)N_(4)can lead tostrong redox capability and high migration speed of the photoinduced charges.Consequently,in thisstudy,W_(18)O_(49)/g‐C_(3)N_(4)hybrids exhibited higher photocatalytic H2 generation than that of pristineg‐C_(3)N_(4)under light irradiation of 420–550 nm.Furthermore,the H2 production rate of thebest‐performing W_(18)O_(49)/g‐C_(3)N_(4)hybrid was 41.5μmol·g^(−1)·h^(−1)upon exposure to monochromaticlight at 550 nm,whereas pure g‐C_(3)N_(4)showed negligible activity.This study promotes novel andenvironmentally friendly hot‐electron‐assisted S‐scheme photocatalysts for the broad‐spectrumutilization of solar light.
基金support from the Research Council of Norway provided by the Norwegian Center for Transmission Electron Microscopy,NORTEM(197405/F50)NTNU NanoLab(grant number 245963)which have provided the characterization toolsthe strategic funding support provided by Department of Chemical Engineering,NTNU,Trondheim,Norway.
文摘To achieve efficient photocatalytic H_(2) generation from water using earth-abundant and cost-effective materials,a simple synthesis method for carbon-doped CdS particles wrapped with graphene(C-doped CdS@G)is reported.The doping effect and the application of graphene as cocatalyst for CdS is studied for photocatalytic H_(2) generation.The most active sample consists of CdS and graphene(CdS-0.15G)exhibits promising photocatalytic activity,producing 3.12 mmol g^-(1) h^-(1) of H_(2) under simulated solar light which is^4.6 times superior than pure CdS nanoparticles giving an apparent quantum efficiency(AQY)of 11.7%.The enhanced photocatalytic activity for H_(2) generation is associated to the narrowing of the bandgap,enhanced light absorption,fast interfacial charge transfer,and higher carrier density(N_(D))in C-doped CdS@G samples.This is achieved by C doping in CdS nanoparticles and the formation of a graphene shell over the C-doped CdS nanoparticles.After stability test,the spent catalysts sample was also characterized to investigate the nanostructure.
基金supported financially by the Academy of Scientific Research and Technology(No.6618,ASRT,Egypt)the National Key R&D Program of China(No.2016YFA0202602),the National Natural Science Foundation of China(Nos.U1663225 and 21805220)+2 种基金the Fundamental Research Funds for the Central Universities(WUT:Nos.2019Ⅲ012GX and 2020Ⅲ002GX)the Hubei Provincial Natural Science Foundation(No.2018CFB242 and 2020CFB416)supported by the State Key Laboratory of Silicate Materials for Architectures and Center for Materials Research and Analysis at Wuhan University of Technology。
文摘Developing anatase/rutile phase-junction in Ti O_(2)to construct Z-scheme system is quite effective to improve its photoelectrochemical activity.In this work,the anatase/rutile phase-junction Ag/Ti O_(2)nanocomposites are developed as photocathodes for hydrogen production.The optimized Ag/Ti O_(2)nanocomposite achieves a high current density of 1.28 m A cm-2,an incident photon-to-current conversion efficiency(IPCE)of 10.8%,an applied bias photon-to-current efficiency(ABPE)of 0.32 at 390 nm and a charge carriers’lifetime up to 2000 s.Such enhancement on photoelectrochemical activity can be attributed to:(ⅰ)the generated Z-scheme system in the anatase/rutile phase-junction Ag/Ti O_(2)photocathode enhances the separation,diffusion and transformation of electron/hole pairs inside the structure,(ⅱ)Ag nanodots modification in the anatase/rutile phases leading to the tuned band gap with enhanced light absorption and(ⅲ)the formed Schottky barrier after Ag nanodots surface modification provides enough electron traps to avoid the recombination of photogenerated electrons and holes.Our results here suggest that developing phase-junction nanocomposite as photocathode will provide a new vision for their enhanced photoelectrochemical generation of hydrogen.
基金the National Natural Science Foundation of China(No.91536105,No.11174186,and No.11074147)the Tianshan Scholar Program.
文摘Reducing sizes of precious metals and utilization of the mixed small clusters of them as catalysts in reactions are important methods due to more active sites for higher catalytic eciency.Based on rst-principles calculations in this work,we found that the platinumbased clusters of Pt3X(X=Al,Si,Cu)which have the magic number 4 can e ectively catalyze the water decomposition and hydrogen production in just one-step reaction process.The adsorbates of the H2O@Pt3X clusters have strong absorption in the ultraviolet and visible regions with wavelength from 300 nm to 760 nm,indicating the sunlight can be used to drive catalytic hydrolysis for producing clean hydrogen.In addition,the O atom remains on the clusters after hydrolysis and can react with CO to form CO2 in activation barrier of 0.340.58 eV,showing the recycling ability of the products after hydrolysis for eliminating the"poisoning"CO by oxidation.Moreover,the formed CO2 molecule can be detached from the Pt3X clusters at 323 K.Our results provide interesting guidance for practical designing the useful photocatalysts.
基金supported by the National Nature Science Foundation of China(Nos.NSFC52072164 and NSFC 32102086)Liaoning Province Science and Technology Planning Project(No.20180551203).
文摘The synthesis of solar-driven chemical value-added products and the degradation of pollutants is a promising approach for sustainable development. However, achieving these works via photocatalysts with efficient charge-separation, photo-absorption is challenging. A yolk-shell CuCo_(2)S_(4)@Cu_(2)O Z-scheme nanoreactor (YS-CuCo_(2)S_(4)@Cu_(2) O-NR) with octahedron Cu_(2)O as the core and tubular CuCo2 S4 as the shell, has been synthesized by regulating composition and morphology. YS-CuCo_(2)S_(4)@Cu_(2)O-NR shows superior photocatalytic activities for producing H_(2) O_(2) collaborates by selective oxidation of benzyl alcohol (BA) to high value-added benzaldehyde (BAD)/utilized Fenton-like reaction to degrade multi-pollutants through space-confinement effect, reaching 80% conversion and 99% selectivity of BA, a yield of 12 mM g^(−1) for H_(2)O_(2) and above 90% degradation efficiency for multi-pollutants. A photocatalysis nanoconfinement reactor system is proposed and demonstrated by using yolk-shell to enhance the performance of the chemical reaction. Mechanism studies show that the yolk-shell provides confined space to accelerate redox reaction kinetics;while the inner void promotes light harvesting and keeps yolk Cu_(2) O from deactivation;combined with the Z-scheme charge transfer, engineering Cu^(+) /Cu^(2+) active composition, they are favorable for enhancing the H_(2) O_(2) generation and Fenton-like activity. These findings provide new opportunities for application of yolk-shell Z-scheme metal-oxide-based photocatalysts.
基金supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(Grant No.52488201)the National Key R&D Program of China(Grant No.2020YFA0714400)。
文摘Renewable energy,such as solar energy,wind energy,and hydraulic energy,mostly belongs to process energy,which is hard to store,while fossil energy belongs to energy-carrier energy,which can achieve long-term storage.Current conversion and utilization technologies for all types of energy mainly focus on power generation.Fossil energy is convenient to store,but its conversion and utilization technologies mainly rely on the combustion of fossil fuels for power and thermal energy generation,emitting huge amounts of pollutants and CO_(2).Power and thermal energy are still process energy which is hard to be stored,and the problem of the low-cost,efficient and long-term storage of energy is difficult to solve,which is the fundamental deficiencies of the current energy production and supply system.H2as an energy-carrier energy enables both clean and efficient use and storage.Therefore,the development of efficient,low-cost,large-scale green H2/power generation is imperative.It is recommended that:(1)new renewable energy units be developed based on integrating H2,thermal energy and power energy poly-generation technology on demand.The already built“sole power generation”renewable energy units should be transformed into H2,thermal energy and power energy poly-generation model,to build a comprehensive energy multi-link supply system that achieves energy storage,transportation and utilization,as well as the full-time,high-efficiency,low-cost conversion and utilization of renewable energy.(2)Developing low-carbon and clean technologies for green H2and power from carbonbased energy sources,achieving efficient energy conversion and full utilization of resources.(3)Building a new industry for high-value conversion and high-quality utilization of fossil fuels to produce the high-value chemical products instead of pollutants which also provides the best solution for large-capacity and long-term energy storage.
基金supported by the National Natural Science Foundation of China(21676213,21476183,51372201)the China Postdoctoral Science Foundation(2016M600809)the Natural Science Basic Research Plan in Shaanxi Province of China(2017JM2026)~~
文摘Ag nanoparticles (NPs) were deposited on the surface of g-C3N4 (CN) by an in situ calcination method. NiS was successfully loaded onto the composites by a hydrothermal method. The results showed that the 10 wt%-NiS/1.0 wt%-Ag/CN composite exhibits excellent photocatalytic H2 generation performance under solar-light irradiation. An H2 production rate of 9.728 mmol·g^-1·h^-1 was achieved, which is 10.82-, 3.45-, and 2.77-times higher than those of pure g-C3N4, 10 wt%-NiS/CN, and 1.0 wt%-Ag/CN composites, respectively. This enhanced photocatalytic H2 generation can be ascribed to the co-decoration of Ag and NiS on the surface of g-C3N4, which efficiently improves light harvesting capacity, photogenerated charge carrier separation, and photocatalytic H2 production kinetics. Thus, this study demonstrates an effective strategy for constructing excellent g-C3N4-related composite photocatalysts for H2 production by using different co-catalysts.
基金supprted by the National Natural Science Foundation of China(51672089,51672099)Specical Funding on Applied Science and Technology in Guangdong(2017B020238005)the State Key Laboratory of Advanced Technology for Material Synthesis and Processing(Wuhan University of Technology)(2015-KF-7)~~
文摘Photocatalysis is believed to be one of the best methods to realize sustainable H2 production. However, achieving this through heterogeneous photocatalysis still remains a great challenge owing to the absence of active sites, sluggish surface reaction kinetics, insufficient charge separation, and a high thermodynamic barrier. Therefore, cocatalysts are necessary and of great significance in boosting photocatalytic H2 generation. This review will focus on the promising and appealing low-cost Ni-based H2-generation cocatalysts as the alternatives for the high-cost and low-abundance noble metal cocatalysts. Special emphasis has been placed on the design principle, modification strategies for further enhancing the activity and stability of Ni-based cocatalysts, and identification of the exact active sites and surface reaction mechanisms. Particularly, four types of modification strategies based on increased light harvesting, enhanced charge separation, strengthened interface interaction, and improved electrocatalytic activity have been thoroughly discussed and compared in detail. This review may open a new avenue for designing highly active and durable Ni-based cocatalysts for photocatalytic H2 generation.
基金financially supported by the Natural Science Foundation of China(No.81660708)Natural Science Foundation of Jiangsu Province of China(Nos.BK20150692,BK20171389)+3 种基金the Key Project of Science and Technology of Tibet(No.2015XZ01G70)the Key Project of Tibet Tibetan Medicine Bureau(No.2017005)open fund by Jiangsu Engineering Technology Research Center of Environmental Cleaning Materials(No.KHK1507)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘In this paper, nanotubes and nanoribbons of sodium titanate structures were synthesized via hydrothermal methods in alkaline solution. CdS decorated titanate nanotubes and nanoribbons were therefore constructed for exploring the performance of hydrogen evolution and synergistic effect of CdS based titanate structures. CdS decorated titanate nanotubes and nanoribbons were characterized by high resolution transmission electron microscopy （HRTEM）, X-ray diffraction （XRD）, UV-vis, Brunauer- Emmett-Teller （BET） and X-ray photoelectron spectroscopy （XPS） measurements. CdS encapsuled in titanate nanotubes （CdS-ETNTs） showed the best capacity of H2 evolution by water splitting and stability than that from the other two structures, i.e., CdS doped titanate nanotubes （CdS-DTNTs） and CdS doped titanate nanoribbons （CdS-DTNRs）, which could be explained by the synergistic effect of decorated CdS with sodium titanate structures and confinement effect of CdS nanoparticles encapsuled inside
文摘Electrocatalytic synthesis of value-added chemicals is attracting significant research attention owing to its mild reaction conditions, environmental benignity, and potentially scalable application to organic synthetic chemistry. Herein, we report the preparation of a single-crystalline NiS2 nanostructure film of N 50 nm thickness grown directly on a carbon fiber doth （NiSJCFC） by a facile vapor-phase hydrothermal （VPH） method. NiSJCFC as an electrocatalyst exhibits activity for both the oxygen evolution reaction （OER） and the hydrogen evolution reaction （HER） in alkaline media. Furthermore, a series of alcohols （2-propanol, 2-butanol, 2-pentanol, and cyclohexanol） were electrocatalytically converted to the corresponding ketones with high selectivity, efficienc and durability using the NiSJCFC electrode in alkaline media. In the presence of 0.45 M alcohol, a remarkably decreased overpotential （- 150 mV, vs. RHE） at the NiS2/CFC anode compared with that for water oxidation to generate O2, i.e., the OER, in alkaline media leads to significantly improved H2 generation. For instance, the H2 generation rate in the presence of 0.45 M 2-propanol is almost 1.2-times of that obtained for pure water splitting, but in a system that employs an applied voltage at least 280 mV lower than that required for water splitting to achieve the same current density （20 mA-crn-2）. Thus, our results demonstrate the applicability of our bifunctional non-precious-metal electrocatalyst for organic synthesis and simultaneous H2 production.
基金financially supported by National Natural Science Foundation of China(22102002,52072001,51872003)Natural Science Foundation of Anhui Province(2108085QE192)。
文摘Spatially isolated oxidation and reduction cocatalysts on a semiconductor can realize efficient charge separation and thereby lead to increased photocatalytic hydrogen generation. However, the effective preparation of such photocatalysts has proven challenging.Herein, we report the facile synthesis of a novel noblemetal-free CdS/MoS/CoPi ternary photocatalyst via a visible light-induced synthesis route, in which MoSreduction cocatalysts were precisely grown on the two terminals of CdS nanorods, while CoPi oxidation cocatalysts were preferentially anchored onto the sidewalls of CdS nanorods. Such spatially isolated MoSand CoPi redox cocatalysts endow CdS nanorods with a rapid charge separation, which enhances their hydrogen generation activity. The CdS/MoS/CoPi photocatalyst with optimized CoPi amount achieves the highest Hgeneration rate of 206 μmol/h, which is 21 and 2 times higher than that achieved by using CdS alone(9.7 μmol/h) and CdS/MoS(105 μmol/h), respectively. The present work highlights the effectiveness of the spatial isolation of reduction and oxidation sites for efficient charge separation and thereby provides a promising strategy for the preparation of highly active photocatalysts.
基金financially supported by the National Natural Science Foundation of China(21003021 and 21373051)
文摘For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the ‘‘spotlight" and given impetus to the universal's efforts to head for the same direction: stem the worst warming and strive for the renewable energy source. Hydrogen peroxide(H_2O_2) is undoubtedly a good choice,which holds the promise as a clean, efficient, safe and transferrable energy carrier. Octahedral coordination polymer, Cd_3(C_3N_3S_3)_2, was found to be a robust photocatalyst for H_2O_2 generation under visible light irradiation. To further improve the H_2O_2 generation efficiency, adhering the octahedron to reduced graphene(rGO) was applied as the strategy herein. The study shows that by adhering Cd_3(C_3N_3S_3)_2to rGO, the formation of H_2O_2 is 2.5-fold enhanced and its deformation is concurrently suppressed. This work not only demonstrates the effectiveness of adhering Cd_3(C_3N_3S_3)_2polymer to rGO for the improvement of the polymer's photocatalytic performance, but also proposes a general way for the fabrication of graphene/coordination compound hybrids for maximizing their synergy.
文摘To further understand the effect of structural defects on the electrochemical and photocatalytic properties of TiO2, two synthetic approaches based on hydrothermal synthesis and post-synthetic chemical reduction to achieve oxygen defect- implantation were developed herein. These approaches led to the formation of TiO2 nanorods with uniformly distributed defects in either the bulk or on the surface, or the combination of both, in the formed TiO2 nanorods （NRs）. Both approaches utilize unique TiN nanoparticles as the reaction precursor. Electron microscopy and Brunauer-Emmett-Teller （BET） analyses indicate that all the studied samples exhibit similar morphology and similar specific surface areas. X-ray photoelectron spectroscopy （XPS） and electron paramagnetic resonance （EPR） data confirm the existence of oxygen defects （Vo）. The photocatalytic properties of TiO2 with different types of implanted Vo were evaluated based on photocatalytic H2 production. By optimizing the concentration of Vo among the TiO2 NRs subjected to different treatments, significantly higher photocatalytic activities than that of the stoichiometric TiO2 NRs was achieved. The incident photon-to-current efficiency （IPCE） data indicate that the enhanced photocatalytic activity arises mainly from defect-assisted charge separation, which implies that photo-generated electrons or holes can be captured by Vo and suppress the charge recombination process. The results show that the defective TiO2 obtained by combining the two approaches exhibits the greatest photocatalytic activity enhancement amon~ all the samples.
