Gd-modified Mn-Co oxides derived from layered double hydroxides for improved catalytic activity and H2O/SO2 tolerance in NH3-SCR of NOx reaction.

Metal oxides derived from layered double hydroxides (LDHs) are expected to obtain low-temperature denitrification (de-NOx) catalysts with high catalytic activity and H2O/SO2 tolerance in the selective catalytic reduction (SCR) of NOx with NH3. In current work, we successfully prepared Gd-modified Mn-Co metal oxides derived from Gd-modified Mn-Co LDHs. The resultant Gd-modified Mn-Co metal oxides exhibit excellent catalytic activity and high H2O/SO2 tolerance in the NH3-SCR de-NOx reaction. The reasons for the enhancement can be ascribed to the unique surface physicochemical properties inherited from LDHs and the modification of Gd, which increase the specific surface area, improve the relative content of Mn4+ and Co3+ on the surface, enhance the number of acidic sites, strengthen the reducibility of catalyst, resulting in the enhanced catalytic activity and H2O/SO2 tolerance. Additionally, it is demonstrated that the NH3-SCR de-NOx reaction occurred on the surface of Gd-modified Mn-Co oxides followed both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms. This study provides us with a design approach to promote catalytic activity and H2O/SO2 tolerance through morphology control and rare earth modification.

Construction of II-type and Z-scheme binding structure in P-doped graphitic carbon nitride loaded with ZnO and ZnTCPP boosting photocatalytic hydrogen evolution.

A ternary heterostructure (ZnPPO) was constructed by loading ZnO and tetrakis (4-carboxyphenyl) zinc porphyrin (ZnTCPP) with P-doped g-C3N4 (PCN). In contrast to binary heterostructures (PCN-ZnO, ZnTCPP-ZnO and ZnTCPP-PCN) and single components (PCN, ZnTCPP and ZnO), ZnPPO has superior photocatalytic activity for H2 generation from water splitting. It is revealed that a binding structure of Ⅱ-type and Z-scheme has been constructed in ZnPPO, which plays a vital role in transferring photo-excited charge carriers. The significant enhancement of photocatalytic activity in ZnPPO is attributed to the effective transfer of photo-generated electrons and holes between the components of the ternary heterostructure.

Introducing Hybrid Defects of Silicon Doping and Oxygen Vacancies into MOF-Derived TiO2-X @Carbon Nanotablets Toward High-Performance Sodium-Ion Storage.

Titanium dioxide (TiO2 ) is a promising anode material for sodium-ion batteries (SIBs), which suffer from the intrinsic sluggish ion transferability and poor conductivity. To overcome these drawbacks, a facile strategy is developed to synergistically engineer the lattice defects (i.e., heteroatom doping and oxygen vacancy generation) and the fine microstructure (i.e., carbon hybridization and porous structure) of TiO2 -based anode, which efficiently enhances the sodium storage performance. Herein, it is successfully realized that the Si-doping into the MIL-125 metal-organic framework structure, which can be easily converted to SiO2 /TiO2-x @C nanotablets by annealing under inert atmosphere. After NaOH etching SiO2 /TiO2-x @C which contains unbonded SiO2 and chemically bonded SiOTi, thus the lattice Si-doped TiO2-x @C (Si-TiO2-x @C) nanotablets with rich Ti3+ /oxygen vacancies and abundant inner pores are developed. When examined as an anode for SIB, the Si-TiO2-x @C exhibits a high sodium storage capacity (285 mAh g-1 at 0.2 A g-1 ), excellent long-term cycling, and high-rate performances (190 mAh g-1 at 2 A g-1 after 2500 cycles with 95.1% capacity retention). Theoretical calculations indicate that the rich Ti3+ /oxygen vacancies and Si-doping synergistically contribute to a narrowed bandgap and lower sodiation barrier, which thus lead to fast electron/ion transfer coefficients and the predominant pseudocapacitive sodium storage behavior.

Insights into the Role of Graphitic Carbon Nitride as a Photobase in Proton-Coupled Electron Transfer in (sp3 )C-H Oxygenation of Oxazolidinones.

Graphitic carbon nitride (g-CN) is a transition metal free semiconductor that mediates a variety of photocatalytic reactions. Although photoinduced electron transfer is often postulated in the mechanism, proton-coupled electron transfer (PCET) is a more favorable pathway for substrates possessing X-H bonds. Upon excitation of an (sp2 )N-rich structure of g-CN with visible light, it behaves as a photobase-it undergoes reductive quenching accompanied by abstraction of a proton from a substrate. The results of modeling allowed us to identify active sites for PCET-the 'triangular pockets' on the edge facets of g-CN. We employ excited state PCET from the substrate to g-CN to selectively cleavethe endo-(sp3 )C-H bond in oxazolidine-2-ones followed by trapping the radical with O2 . This reaction affords 1,3-oxazolidine-2,4-diones. Measurement of the apparent pKa value and modeling suggest that g-CN excited state can cleave X-H bonds that are characterized by bond dissociation free energy (BDFE) ≈100 kcal mol-1 .

Rational Regulation of Reducibility and Acid Site on Mn-Fe-BTC to Achieve High Low-Temperature Catalytic Denitration Performance.

Selective catalytic reduction with ammonia is the mainstream technology of flue gas denitration (de-NOx). The reducibility and acid site are two important factors affecting the de-NOx performance, and effective regulation between them is the key to obtain a highly efficient de-NOx catalyst. Herein, a series of Mn-Fe-BTC with different ratios of Mn and Fe are synthesized, among which 2Mn-1Fe-BTC with 2:1 molar ratio of Mn and Fe has excellent low-temperature (LT) de-NOx performance (above 90% NO conversion between 60 and 270 °C) and good tolerance to H2O and SO2 poisoning (88% NO conversion at 150 °C with 100 ppm of SO2 and/or 6% H2O). It is revealed that the reducibility properties and acid sites of Mn-Fe-BTC can be flexibly tuned by the ratio of Mn and Fe. The difference in electronegativity between Fe and Mn leads to the redistribution of valence electrons, which enables the controllable reducibility of Mn-Fe-BTC. Furthermore, different amounts of Mn and Fe lead to different electron transport, which determines the type and number of acid sites. The synergistic effect of Mn and Fe endows Mn-Fe-BTC with enhanced surface molecular adsorption capacity and enables the catalyst to selectively chemisorb NH3 and NO at different active sites. This research provides guidance for the flexible regulation of reducibility and acid site of LT de-NOx catalyst.

Zinc and phosphorus poisoning tolerance of Cu-SSZ-13 and Ce-Cu-SSZ-13 in the catalytic reduction of nitrogen oxides.

SSZ-13 has been commercialized as a catalyst in diesel engines for the selectivity catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3-SCR), but the catalyst is facing the problem of poisoning. Herein, two well-designed catalysts, Cu-SSZ-13 and cerium (Ce) doped Cu-SSZ-13 are synthesized, and their tolerance to zinc (Zn) and phosphorus (P) poisoning alone and together are explored in detail. The research found that Zn and P poisoning alone leads to the destruction of Cu-SSZ-13 structure, resulting in the decline of denitration (de-NOx) performance following the mechanism dominated by Eley-Rideal (E-R). Surprisingly, it is found that zinc phosphate particles are formed at inactive sites on the surface of Cu-SSZ-13 in the presence of Zn and P together, which protects the active sites, enhances the adsorption of nitric oxide. As a result, the excellent de-NOx performance of Cu-SSZ-13 is well maintained following the dual mechanism of E-R and Langmuir-Hinshelwood (L-H). In addition, the introduction of Ce stabilizes the active sites, so as to improve the de-NOx performance and the poisoning tolerance of Cu-SSZ-13. This work deeply analyzes the reasons of Zn and P poisoning and the positive effect of Ce on Cu-SSZ-13, which provides ideas for improving the poisoning tolerance of Cu-SSZ-13 and promotes the further application.

PdS Quantum Dots as a Hole Attractor Encapsulated into the MOF@Cd0.5Zn0.5S Heterostructure for Boosting Photocatalytic Hydrogen Evolution under Visible Light.

Herein, a new photocatalyst PdS@UiOS@CZS is successfully synthesized, where thiol-functionalized UiO-66 (UiOS), a metal-organic framework (MOF) material, is used as a host to encapsulate PdS quantum dots (QDs) in its cages, and Cd0.5Zn0.5S (CZS) solid solution nanoparticles (NPs) are anchored on its outer surface. The resultant PdS@UiOS@CZS with an optimal ratio between components displays an excellent photocatalytic H2 evolution rate of 46.1 mmol h-1 g-1 under visible light irradiation (420∼780 nm), which is 512.0, 9.2, and 5.9 times that of pure UiOS, CZS, and UiOS@CZS, respectively. The reason for the significantly enhanced performance is that the encapsulated PdS QDs strongly attract the photogenerated holes into the pores of UiOS, while the photogenerated electrons are effectively migrated to CZS due to the heterojunction effect, thereby effectively suppressing the recombination of charge carriers for further high-efficiency hydrogen production. This work provides an idea for developing efficient photocatalysts induced by hole attraction.

An electron-hole separation mechanism caused by the pseudo-gap formed at the interfacial Co-N bond between cobalt porphyrin metal organic framework and boron-doped g-C3N4 for boosting photocatalytic H2 production.

Photocatalytic hydrogen evolution from water splitting presents an attractive prospect in dealing with the energy crisis, but the low efficiency of charge separation and migration still seriously hinders its further practical application. Here, an acidified boron-doped g-C3N4 (HBCNN) and cobalt porphyrin metal organic frameworks (CoPMOF) self-assembled two-dimensional and two-dimensional (2D/2D) hybrid photocatalyst is fabricated successfully. The resultant HBCNN/CoPMOF with optimum ratio exhibits a superior H2 evolution rate of 33.17 mmol g-1 h-1, which is 3.04 and 100.50 times higher than the single HBCNN and CoPMOF, respectively. It is found that a coordination connection has formed between CoPMOF and HBCNN through Co-N bond, and the interfacial Co-N bond then forms a pseudo-gap in the up-spin channel of electronic states, establishing an electron-hole separation mechanism. It is this electron-hole separation mechanism that contributes to a Z-scheme transport mode of photogenerated carriers, which greatly promotes the photocatalytic H2 production performance of HBCNN/CoPMOF heterostructure. This work may provide an idea for the design of heterojunction to improve the photocatalytic performance by constructing electron-hole separation through interfacial bond.

Flexible and robust silicon/carbon nanotube anodes exhibiting high areal capacities.

The fast development of flexible devices has greatly boosted the demands for flexible lithium-ion batteries (LIBs). Accordingly, a broad exploration of flexible electrodes in LIBs is crucial. At present, the major challenge in the flexible electrode for lithium-ion batteries (LIBs) is how to achieve an excellent electrochemical performance (particularly high-energy density) while maintaining superior mechanical flexibility. Herein, flexible silicon/carbon nanotube (Si/CNT) electrode is prepared via a common blade-coating, which is adoptable to large-scale production. The CNT network from monodispersed CNT solution endows the electrode with superior tensile strength and mechanical toughness. The tensile strength of the flexible electrodes is up to 3.75 MPa, and the corresponding strain at break is 43.9%. The flexible electrode delivers an areal capacity of 10.6 mAh cm-2 at 0.06 mA cm-2, which is completely meet the practical requirement (1-3 mAh cm-2). And a high reversible capacity of 5.64 mAh cm-2 can be retained at 0.3 mA cm-2 after 200 cycles. In addition, the pouch cell exhibits a promising cycling stability under the repeated deformation state. Moreover, this work also provides a feasible and scalable method to fabricate flexible electrodes for other wearable energy storage systems.

Red edge effect and chromoselective photocatalysis with amorphous covalent triazine-based frameworks.

Chromoselective photocatalysis offers an intriguing opportunity to enable a specific reaction pathway out of a potentially possible multiplicity for a given substrate by using a sensitizer that converts the energy of incident photon into the redox potential of the corresponding magnitude. Several sensitizers possessing different discrete redox potentials (high/low) upon excitation with photons of specific wavelength (short/long) have been reported. Herein, we report design of molecular structures of two-dimensional amorphous covalent triazine-based frameworks (CTFs) possessing intraband states close to the valence band with strong red edge effect (REE). REE enables generation of a continuum of excited sites characterized by their own redox potentials, with the magnitude proportional to the wavelength of incident photons. Separation of charge carriers in such materials depends strongly on the wavelength of incident light and is the primary parameter that defines efficacy of the materials in photocatalytic bromination of electron rich aromatic compounds. In dual Ni-photocatalysis, excitation of electrons from the intraband states to the conduction band of the CTF with 625 nm photons enables selective formation of C‒N cross-coupling products from arylhalides and pyrrolidine, while an undesirable dehalogenation process is completely suppressed.

Polyvinylpyrrolidone regulated synthesis of mesoporous titanium niobium oxide as high-performance anode for lithium-ion batteries.

TiNb2O7 (TNO) as a promising candidate anode for lithium-ion batteries (LIBs) shows obvious advantages in terms of specific capacity and safety, but which undergoes the intrinsic poor electrical and ionic conductivity. Herein, we propose a simple synthesis strategy of mesoporous TNO via a polymeric surfactant-mediated evaporation-induced sol-gel method, using polyvinylpyrrolidone (PVP) with different molecular weights (average Mw: 10000/58000/1300000) as the regulating agent, which greatly affects the lithium storage performance of the as-prepared TNO. The optimized TNO (i.e., PVP of 58000) delivers a high reversible capacity of 303.1 mAh/g at 1 C, with a retention rate of 73.4% (222.5 mAh/g) after 300 cycles. Even at 5 C, a high reversible capacity of 185.6 mAh/g can be achieved, with a retention rate of 72.3% after 1000 cycles. The superior lithium storage behavior is attributed to the fine mesoporous framework consisting of interconnected TNO nanocrystallites with high specific surface area and high mesoporosity, which greatly increases the active sites, improves the Li+ diffusion kinetics and alleviates volume fluctuation induced by the repetitive Li+ insertion-extraction processes.

Hydrogen spillover effect induced by ascorbic acid in CdS/NiO core-shell p-n heterojunction for significantly enhanced photocatalytic H2 evolution.

A new variety of CdS/NiO core-shell p-n heterojunction is synthesized by in-situ chemically depositing NiO shell on single-crystal CdS nanorods for the first time. With this method, the range of NiO shell thickness can be accurately controlled within a few nanometers. The optimized CdS/NiO sample (CSN0.5) with a NiO shell layer of 1.5 nm exhibits a highly efficient photocatalytic H2 evolution rate of 731.7 µmol/h (corresponding to 243.9 mmol/g/h) without using co-catalyst, which is among the highest value of all the CdS-based photocatalysts. The apparent quantum efficiency (AQE) of CSN0.5 at 365 nm wavelength reaches 28.19%. The remarkably enhanced photocatalytic performance can be attributed to a hydrogen spillover effect induced by ascorbic acid in CdS/NiO, which promotes the transmission of adsorbed H* from hydrogen-rich NiO (electron-poor region) to hydrogen-poor CdS (electron-rich region) where the adsorbed H* reacts in time with the photogenerated electron to produce H2, facilitating the H2 evolution reaction. This work provides a method to promote the photocatalytic H2 evolution reaction by using hydrogen spillover effect.

Enhanced Organic Photocatalysis in Confined Flow through a Carbon Nitride Nanotube Membrane with Conversions in the Millisecond Regime.

Bioinspired nanoconfined catalysis has developed to become an important tool for improving the performance of a wide range of chemical reactions. However, photocatalysis in a nanoconfined environment remains largely unexplored. Here, we report the application of a free-standing and flow-through carbon nitride nanotube (CNN) membrane with pore diameters of 40 nm for confined photocatalytic reactions where reactants are in contact with the catalyst for <65 ms, as calculated from the flow. Due to the well-defined tubular structure of the membrane, we are able to assess quantitatively the photocatalytic performance in each of the parallelized single carbon nitride nanotubes, which act as spatially isolated nanoreactors. In oxidation of benzylamine, the confined reaction shows an improved performance when compared to the corresponding bulk reaction, reaching a turnover frequency of (9.63 ± 1.87) × 105 s-1. Such high rates are otherwise only known for special enzymes and are clearly attributed to the confinement of the studied reactions within the one-dimensional nanochannels of the CNN membrane. Namely, a concave surface maintains the internal electric field induced by the polar surface of the carbon nitride inside the nanotube, which is essential for polarization of reagent molecules and extension of the lifetime of the photogenerated charge carriers. The enhanced flow rate upon confinement provides crucial insight on catalysis in such an environment from a physical chemistry perspective. This confinement strategy is envisioned not only to realize highly efficient reactions but also to gain a fundamental understanding of complex chemical processes.

Flexible S@C-CNTs cathodes with robust mechanical strength via blade-coating for lithium-sulfur batteries.

Lithium sulfur batteries (LSBs) with high energy density hold some promising applications in the wearable and flexible devices. However, it has been still challenging to develop a simple and feasible approach to prepare flexible LSB cathodes with both robust mechanical strength. Herein, flexible S@C-CNTs cathodes with controllable thicknesses are successfully fabricated via a facile blade-coating method. Due to the strong cohesion among CNTs bundles and the well-designed structure, the flexible S@C-CNTs cathodes are demonstrated to be with a combination of impressive mechanical strength and enhanced electrochemical performance. For the flexible S@C-CNTs cathodes with the sulfur mass loading of 4 mg cm-2, the areal capacity is close to 3.0 mA h cm-2, and the breaking stress is up to 5.59 MPa with 7.77% strain. Meanwhile, the pouch cell exhibits excellent cyclic stability at both flat/bent conditions. All demonstrate that the flexible S@C-CNTs cathodes may satisfy the demands of practical application. Moreover, this methodology is suitable for designing other flexible battery electrodes, such as flexible Si@C-CNTs anodes for lithium ion batteries, flexible P@C-CNTs anodes for sodium/potassium ion batteries, etc.

Thio linkage between CdS quantum dots and UiO-66-type MOFs as an effective transfer bridge of charge carriers boosting visible-light-driven photocatalytic hydrogen production.

Metal-organic frameworks (MOFs)/semiconductor hybrids have attracted attention in photocatalysis. Herein, we report a new strategy to use thiol-laced UiO-66 (UiO-66-(SH)2) as a porous and functional support for anchoring CdS quantum dots (QDs) (size: 0.5/3 nm). Cd2+ ions are firstly absorbed into the cavities of UiO-66-(SH)2 MOFs via coordinating to the thiol groups in the presence of a base to produce UiO-66-(S-Cd)2, then thiourea is added to form UiO-66-(S-CdS)2 (abbreviated as UiOS-CdS). It is clearly revealed by ultrafast transient absorption spectroscopy that the thio linkage between UiO-66 and CdS acts as an effective transfer bridge of charge carriers, which greatly promotes the interface transfer process of photogenerated electrons and holes, boosting the photocatalytic hydrogen production performance from water splitting. The optimized UiOS-CdS exhibits a photocatalytic H2 production rate of 153.2 µmol h-1 (10 mg of catalyst) under visible-light irradiation (λ > 420 nm) in the absence of nobel metal co-catalyst, corrsponding to an apparent quantum efficiency of 11.9% at 420 nm. This work may provide an effective strategy to construct QDs-linker-MOFs stylephotocatalysts for efficient energy conversion.

Pd-based catalysts promoted by hierarchical porous Al2O3 and ZnO microsphere supports/coatings for ethyl acetate highly active and stable destruction.

Developing economical and active materials is of great significance for VOC purification. Here, hierarchical porous Al2O3 and ZnO microspheres (Al2O3-pm and ZnO-pm) were synthesized by a facile hydrothermal strategy. The urchin-like Al2O3-pm and flower-like ZnO-pm possess high specific surface area (especially; external surface area) obviously boost the dispersion of Pd with 29.3 % and 30.1 % over Pd/Al2O3-pm and Pd/ZnO-pm, respectively, over 3.4 times higher than those of commercial Al2O3- and ZnO-supported counterparts. Pd/Al2O3-pm possesses excellent activity and CO2 yield in ethyl acetate (EA) degradation, with TOF reaches 7.76 × 10-3 s-1 at 160 °C under GHSV of 50,000 h-1. Moreover, Pd/Al2O3-pm exhibits satisfied performance in EA-contained binary VOCs oxidation and has high long-term stability under both dry and humid conditions. Both Pd sites and Brønsted acid sites participated in reaction process and initially react with EA to form ethylene and ethanol, respectively. Larger amount Brønsted acid sites over Pd/Al2O3-pm promote ethanol formation and C-C cleavage, resulting in different CO2 yields and EA activation mechanisms. The coating greatly enhances Pd dispersion over Pd supported monolithic catalyst, endowing its desired activity and stability even with a much lower Pd loading. This work promotes the potential application of noble-metal-based monolithic materials in VOC degradation.

The deposition of VWOx on the CuCeOy microflower for the selective catalytic reduction of NOx with NH3 at low temperatures.

NOx emissions are a major environmental problem, and the selective catalytic reduction (SCR) is the most effective method to convert NOx in flue gas into harmless N2 and H2O. In this work, a new carrier, CuCeOy microflower assembled from a large number of copper-cerium mixed oxide nanosheets, is firstly developed to load vanadium-tungsten mixed oxides (VWOx) for the SCR of NOx with NH3. The resultant optimal VWOx/CuCeOy catalyst exhibits significantly enhanced low-temperature de-NOx performance with the NOx conversion of 60% at 180 °C, over 90% from 240 °C to 390 °C under the gas hourly space velocity (GHSV) of 36,000 h-1. The reason can be mainly attributed the fact that the transfer of electrons among Ce, Cu and V ions is very easy to occur via the following equations Ce3++Cu2+ â†” Ce4++Cu+, V5+ + Cu+ â†” V4+ + Cu2+, V4+ + Ce4+ â†” V5+ + Ce3+, which effectively decreases the apparent activation energy (Ea = 16.59 kJ/mol) of NH3-SCR de-NOx reaction. In addition, the enhanced reducibility and a large number of Brønsted acid sites also contribute the low-temperature de-NOx performance. Both Eley-Rideal and Langmuir-Hinshelwood mechanisms are included in the NH3-SCR de-NOx reaction over the VWOx/CuCeOy catalyst.

Embedding CoMoO4 nanoparticles into porous electrospun carbon nanofibers towards superior lithium storage performance.

CoMoO4 nanoparticles have been successfully in-situ formed and simultaneously embedded within the porous carbon nanofibers (CoMoO4/CNFs) via a facile electrospinning-annealing strategy. The porous CoMoO4/CNFs exhibit a specific surface area of 255.3 m2/g and a pore volume of 0.52 cc/g with average pore diameter of 43.5 nm. The carbon content in the CoMoO4/CNFs can be readily controlled by adjusting the annealing temperature. When examined as anode materials for lithium ion batteries (LIBs), the CoMoO4/CNFs demonstrate superior electrochemical performance, delivering a high reversible capacity of 802 mA h/g after 200 cycles at 200 mA/g and a high-rate capacity of 574 mA h/g at 2000 mA/g. The excellent lithium storage behavior can be attributed to the incorporation of CoMoO4 nanoparticles into the porous N-doped graphitic carbon nanofibers, which efficiently buffer the volume changes of CoMoO4 upon lithiation/delithiation and maintain the overall electrode conductivity/integrity.

Casting amorphorized SnO2/MoO3 hybrid into foam-like carbon nanoflakes towards high-performance pseudocapacitive lithium storage.

We report an amorphorization-hybridization strategy to enhance lithium storage by casting atomically mixed amorphorized SnO2/MoO3 into porous foam-like carbon nanoflakes (denote as SnO2/MoO3@CNFs, or SMC in short), which are simply prepared by annealing tin(II)/molybdenum(IV) 2-ethylhexanoate within CNFs under ambient atmosphere at a low temperature (300 °C). The SnO2/MoO3 loading amount within CNFs can be easily adjusted by controlling the Sn/Mo/C precursors. When examined as lithium ion battery (LIB) anode materials, the amorphorized SnO2/MoO3@CNFs with carbon content of 32 wt% (also denote as SMC-32, in which the number represents the carbon content) deliver a high reversible capacity of 1120.5 mA h/g after 200 cycles at 200 mA/g and then 651.5 mA h/g after another 300 cycles at 2000 mA/g, which is much better than that of the crystalline SnO2/CNFs (carbon content of 34 wt%), MoO3/CNFs (carbon content of 22.7 wt%), or SnO2/MoO3@CNFs (with lower carbon contents of 11 and 25 wt%). The electrochemical measurements as well as the ex situ structure characterization clearly suggest that combination of amorphorization and hybridization of SnO2/MoO3 with CNFs synergistically contributes to the superior lithium storage performance with high pseudocapacitive contribution.

The synergy between electronic anchoring effect and internal electric field in CdS quantum dots decorated dandelion-like Fe-CeO2 nanoflowers for improved photocatalytic hydrogen evolution.

A series of dandelion-like Fe-CeO2/CdS (FeCex/Cdy) nanoflowers with different molar ratios of Fe-CeO2 to CdS are synthesized by solvothermal method for the first time. The FeCex/Cdy nanoflowers are assembled by a large number of nanoparticles with the diameter of about 3 nm, and the introduction of Fe ions and the couple of CdS quantum dots (QDs) efficiently enhanced the relative percentage of Ce3+ in CeO2. The as-obtained FeCe1/Cd1 heterostructure exhibits the highest photocatalytic H2 evolution ability of 108.9 µmol/h, which is 20.5, 6.1 and 7.1 times higher than CeO2, Fe-CeO2 and CdS, respectively. This significantly enhanced photocatalytic performance can be mainly attributed to the synergy between the electronic anchoring effect of Fe3+/Fe2+ and Ce4+/Ce3+ redox couples and the internal electric field constructed by the II-type heterojunction between Fe-CeO2 and CdS. This work provides a new idea for the design of efficient photocatalysts by combining the advantages of heterostructure and ion anchoring effect.