Synthesis of magnetic bentonite-gelatin hydrogel beads and their applications in Cu2+ capturing.

Heavy metal ions that exist in groundwater and farmland jeopardize the ecological environment and are very difficult to remove because of the complicated actual environment. Raw bentonite-gelatin beads (RB-GT) and magnetic bentonite-gelatin beads (MB-GT) synthesized in this work would be an appropriate tool to solve this problem. Those beads are synthesized by a facile hybrid injection method. Their adsorption behaviors on Cu(II) ions were systematically investigated using the batch adsorption method. The beads were characterized by scan electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption isotherm and adsorption kinetic study showed that the Cu2+ adsorption by MB-GT beads fitted the Langmuir model and the pseudo-second model. The adsorption maximum capacities reached 192.5 mg/g and 236.5 mg/g with Cu concentration of 1000 mg/L for RB-GT and MB-GT beads, respectively. The competitive adsorption with other heavy metal ions (Ni(II), Pd(II) and Cd(II)) were compared. The adsorption of Cu(II) mechanisms is also further discussed.

The construction of lattice-matched CdS-Ag2S heterojunction photocatalysts: High-intensity built-in electric field effectively boosts bulk-charge separation efficiency.

The built-in electric field of heterojunction can effectively promote carrier separation and transfer. While, its interface orientation is often random, leading to lattice mismatch and high resistance, thus limiting the efficiency of interfacial charge transfer. Herein, the lattice-matched heterojunction (CdS-Ag2S) was constructed by ion-exchange epitaxial growth. The results of surface photovoltage spectroscopy (SPV), transient photovoltage spectroscopy (TPV), and time-resolved photoluminescence (TRPL) show that the lattice-matched heterojunction has higher charge separation efficiency and longer photogenerated carrier lifetime than that of lattice-mismatched one. The lattice-matched CdS-Ag2S has a high built-in electric field (BIEF) value of 103.42 and a bulk-charge separation (BCS) efficiency of 68.71%, which is about three times higher than that of the lattice-mismatched heterojunction (CdS-Ag2S-M). In addition, the photodegradation efficiency of CdS-Ag2S towards norfloxacin (NOR) was also 3.4 times higher than that of CdS-Ag2S-M. The above results and density functional theory (DFT) calculations indicate that improving the lattice matching at the heterojunction is beneficial for establishing a high-intensity built-in electric field and effectively promoting bulk-charge separation efficiency, thus achieving excellent photocatalytic performance. This work provides an essential reference for the research of high-performance heterojunction photocatalysts.

Theoretical Study on the Swelling Mechanism and Structural Stability of Ni3Al-LDH Based on Molecular Dynamics.

layered double hydroxide (LDH) as a kind of 2D layer material has a swelling phenomenon. Because swelling significantly affects the adsorption, catalysis, energy storage, and other application properties of LDHs, it is essential to study the interlayer spacing, structural stability, and ion diffusion after swelling. In this paper, a periodic computational model of Ni3Al-LDH is constructed, and the supramolecular structure, swelling law, stability, and anion diffusion properties of Ni3Al-LDH are investigated by molecular dynamics theory calculations. The results show that the interlayer water molecules of Ni3Al-LDH present a regular layered arrangement, combining with the interlayer anions by hydrogen bonds. As the number of water molecules increases, the hydrogen bond between the anion and the basal layer gradually weakens and disappears when the number of water molecules exceeds 32. The hydrogen bond between the anion and the water molecule gradually increases, reaching an extreme value when the number of water molecules is 16. The interlayer spacing of Ni3Al-LDH is not linear with the number of water molecules. The interlayer spacing increases slowly when the number of water molecules is more than 24. The maximum layer spacing is stable at around 19 Å. The interlayer spacing, binding energy, and hydration energy show an upper limit for swelling: the number of water molecules is 32. When the number of interlayer water molecules is 16, the water molecules' layer structure and LDH interlayer spacing are suitable for anions to obtain the maximum diffusion rate, 10.97 × 10-8 cm2·s-1.

Construction dual vacancies to regulate the energy band structure of ZnIn2S4 for enhanced visible light-driven photodegradation of 4-NP.

Most of the intrinsic photocatalysts with visible light response can only generate one active radical due to the limitation of their band structures, which is immediate cause limiting their photocatalytic degradation performance. In this work, ZnIn2S4 with Zn vacancy and S vacancy (VZn+S-ZnIn2S4) was prepared for the first time. As expected, the VZn+S-ZnIn2S4 exhibits remarkable photocatalytic performance for 4-Nitrophenol (4-NP) degradation under visible light and the apparent rate constant is about 11 times that of pristine ZnIn2S4. The construction of dual vacancies can regulate the energy band structure of the ZnIn2S4, enabling it to generate •OH and •O2- simultaneously. Meanwhile, dual vacancies system can also extremely improve the separation efficiency of carriers. It is worth noting that Zn vacancy and S vacancy can capture photogenerated holes and photogenerated electrons, respectively, which is beneficial for photogenerated carriers to participate in radical generation reactions. In addition, a possible 4-NP degradation pathway was proposed based on HPLC-MS analysis. This work provides a new way to construct photocatalysts for photodegradation of pollutants in wastewater.

Direct Z-scheme CeO2@LDH core-shell heterostructure for photodegradation of Rhodamine B by synergistic persulfate activation.

Photocatalytic activation of persulfate (PAPS) is considered an efficient and green approach for the mitigation of organic pollutants because of its advantages in low energy consumption and high reusability of photocatalysts. Herein, direct Z-scheme CeO2@LDH heterojunction photocatalyst with a core-shell structure is constructed. We reveal that CeO2@LDH exhibits excellent persulfate (PS) activation performance and high degradation efficiency of RhB under visible light irradiation. Control experiments by quenching catalytically active radicals and analysis of electron paramagnetic resonance (ESR) spectra suggest that the sulfate radical (SO4·-) generated by photocatalytic activation of PS, together with superoxide radical (·O2-) and hydroxyl radical (·OH), degrade pollutants synergistically. Density functional theory (DFT) calculations indicate that the built-in electric field across the surface of CeO2 and LDH is the intrinsic driving force for the efficient transfer of hot carriers in the Z-scheme heterojunction. The construction of this transfer path can effectively engineer the interfacial band structure and inhibit the recombination of photogenerated electron-hole pairs and promote their transportation. Meanwhile, electrons were found to accumulate at the conduction band (CB) of LDHs and holes populate at valence band (VB) of CeO2, generating more active species for photodegradation of RhB. We demonstrate that the Z-scheme heterojunction photocatalyst activated PS system (Z-scheme/PS) is a promising method to degrade RhB and potentially organic pollutants in general.

Experimental and Theoretical Investigations into the Performance and Mechanism of CO2 Capture by 3D and 2D ZnAl Layered Double Hydroxides.

Two-dimensional (2D) materials have a wide range of applications in adsorption and catalysis because of their high specific surface areas and large number of surface active sites. In this paper, bulk ZnAl layered double hydroxides (ZnAl-LDHs or bulk-LDHs) and 2D monolayer ZnAl-LDHs (monolayer-LDHs) were constructed and used for CO2 capture at temperatures of 298-573 K. The experimental results show that monolayer-LDHs have a large specific surface area (455 m2 g-1) and shows an excellent CO2 capture performance (4.5 mmol g-1). The CO2 adsorption capacity of monolayer-LDHs decreases greatly with an increase of the temperature, while bulk-LDHs are less affected by the temperature. Moreover, the parameters of charge distribution, density of states, and charge transfer of bulk-LDHs and monolayer-LDHs were studied in detail by density functional theory, and the difference of the adsorption mechanism between two LDH materials in CO2 capture was compared. It is found that monolayer-LDHs have better electronic activity than bulk-LDHs. At low temperature, CO2 is more likely to be physically adsorbed on the surface of monolayer-LDHs, and the adsorption process is more likely to occur. CO2 is more easily adsorbed on the surface of bulk-LDHs in the form of chemisorption, the adsorption energy is larger (-1.01 eV), but the CO2 capture capacity is quite stable at high temperature.

Anchoring SnS2 on TiC/C Backbone to Promote Sodium Ion Storage by Phosphate Ion Doping.

Tin disulfide (SnS2 ) shows promising properties toward sodium ion storage with high capacity, but its cycle life and high rate capability are still undermined as a result of poor reaction kinetics and unstable structure. In this work, phosphate ion (PO4 3- )-doped SnS2 (P-SnS2 ) nanoflake arrays on conductive TiC/C backbone are reported to form high-quality P-SnS2 @TiC/C arrays via a hydrothermal-chemical vapor deposition method. By virtue of the synergistic effect between PO4 3- doping and conductive network of TiC/C arrays, enhanced electronic conductivity and enlarged interlayer spacing are realized in the designed P-SnS2 @TiC/C arrays. Moreover, the introduced PO4 3- can result in favorable intercalation/deintercalation of Na+ and accelerate electrochemical reaction kinetics. Notably, lower bandgap and enhanced electronic conductivity owing to the introduction of PO4 3- are demonstrated by density function theory calculations and UV-visible absorption spectra. In view of these positive factors above, the P-SnS2 @TiC/C electrode delivers a high capacity of 1293.5 mAh g-1 at 0.1 A g-1 and exhibits good rate capability (476.7 mAh g-1 at 5 A g-1 ), much better than the SnS2 @TiC/C counterpart. This work may trigger new enthusiasm on construction of advanced metal sulfide electrodes for application in rechargeable alkali ion batteries.

Coupling a Sponge Metal Fibers Skeleton with In Situ Surface Engineering to Achieve Advanced Electrodes for Flexible Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are regarded as promising next-generation energy storage systems, however, the uncontrollable dendrite formation and serious polysulfide shuttling severely hinder their commercial success. Herein, a powerful 3D sponge nickel (SN) skeleton plus in situ surface engineering strategy, to address these issues synergistically, is reported, and a high-performance flexible LSB device is constructed. Specifically, the rationally designed spray-quenched lithium metal on the SN matrix (solid electrolyte interface (SEI)@Li/SN), as dendrite inhibitor, combines the merits of the 3D lithiophilic SN skeleton and the in situ formed SEI layer derived from the spray-quenching process, and thereby exhibits a steady overpotential within 75 mV for 1500 h at 5 mA cm-2 /10 mA h cm-2 . Meanwhile, in situ surface sulfurization of the SN skeleton hybridizing with the carbon/sulfur composite (SC@Ni3 S2 /SN) serves as efficient lithium polysulfide adsorbent to catalyze the overall reaction kinetics. COMSOL Multiphysics simulations and density functional theory calculations are further conducted to explore the underlying mechanisms. As a proof of concept, the well-designed SEI@Li/SN||SC@Ni3 S2 /SN full cell shows excellent electrochemical performance with a negative/positive ratio in capacity of ≈2 and capacity retention of 99.82% at 1 C under mechanical deformation. The novel design principles of these materials and electrodes successfully shed new light on the development of flexible LSBs.

A low-temperature water-gas shift reaction catalyzed by hybrid NiO@NiCr-layered double hydroxides: catalytic property, kinetics and mechanism investigation.

The realization of a high efficiency water gas shift reaction (WGSR) at low temperatures has always been a research hotspot and is difficult to achieve. Based on NiCr layered double hydroxides (NiCr-LDHs), a hybrid NiO@NiCr-LDH was prepared by intercalation and surface complexing. The above materials were applied to WGSR at low temperatures, and the catalytic activity and reaction mechanism of WGSR with NiCr-LDHs and LDHs intercalated with organic metal ligands (NiCr-Ni/SB-LDHs) were compared. It was found that the activity of NiO@NiCr-LDHs was about 4 and 2 times higher than that of NiCr-LDHs and NiCr-Ni/SB-LDHs, respectively. At 150 °C, the CO conversion of NiO@NiCr-LDHs is 35.2%, the reaction rate is 19.71 µmol gcat-1 s-1, the TOF value is 0.225 s-1, and the activation energy is 77.4 kJ mol-1. In addition, the complexing NiO content has a great influence on the activity of NiO@NiCr-LDHs for WGSR. In addition, DFT calculations were used to compare the differences in the performance and catalytic mechanism of different nickel containing LDH catalysts for WGSR. According to the calculated results of relative energy barrier and activation energy, a possible reaction pathway and mechanism are discussed. The results show that compared with NiCr-LDHs and NiCr-Ni/SB-LDHs, NiO@NiCr-LDHs can effectively reduce the activation energy of the H2O dissociation step, which is the rate determining step of WGSR.

Puffed Rice Carbon with Coupled Sulfur and Metal Iron for High-Efficiency Mercury Removal in Aqueous Solution.

Development of low-cost, high-efficiency, and environmentally benign adsorbents for mercury removal is of significant importance for environmental remediation. Herein, we report a novel porous puffed rice carbon (PRC) with co-implanted metal iron and sulfur, forming a high-quality PRC/Fe@S composite as a high-efficiency adsorbent for mercury removal from aqueous solution. The in situ-formed Fe nanoparticles in PRC are strongly coupled with sulfur via a supercritical CO2 fluid approach and dispersed homogeneously in the cross-linked hierarchical porous architecture. The pore formation mechanism of Fe on PRC is also proposed. The optimized PRC/Fe@S composite offers superior selective affinity, high removal efficiency, and ultrahigh adsorption capacity of up to 738.0 mg g-1. It is demonstrated that the hierarchical porous carbon in the PRC/Fe@S composite not only acts as a framework to stabilize and disperse Fe nanoparticles but also provides abundant pores and voids for absorbing Hg(II) from aqueous solution. More importantly, the absorbed Hg(II) can be reduced to Hg(0) by Fe and further chemically immobilized by sulfur. The enhanced coupled effect is discussed and proposed. Therefore, an innovative adsorption mechanism of adsorption-reduction-immobilization is proposed, which offers a new prospect in developing high-efficiency carbon-based adsorbents in environmental remediation.

Boosting fast energy storage by synergistic engineering of carbon and deficiency.

Exploring advanced battery materials with fast charging/discharging capability is of great significance to the development of modern electric transportation. Herein we report a powerful synergistic engineering of carbon and deficiency to construct high-quality three/two-dimensional cross-linked Ti2Nb10O29-x@C composites at primary grain level with conformal and thickness-adjustable boundary carbon. Such exquisite boundary architecture is demonstrated to be capable of regulating the mechanical stress and concentration of oxygen deficiency for desired performance. Consequently, significantly improved electronic conductivity and enlarged lithium ion diffusion path, shortened activation process and better structural stability are realized in the designed Ti2Nb10O29-x@C composites. The optimized Ti2Nb10O29-x@C composite electrode shows fast charging/discharging capability with a high capacity of 197 mA h g-1 at 20 C (∼3 min) and excellent long-term durability with 98.7% electron and Li capacity retention over 500 cycles. Most importantly, the greatest applicability of our approach has been demonstrated by various other metal oxides, with tunable morphology, structure and composition.

Rational synthesis of Cr0.5Nb24.5O62 microspheres as high-rate electrodes for lithium ion batteries.

Controllable fabrication of advanced electrode materials is critical for the development of lithium ion batteries (LIBs). Herein, for the first time, we report novel hierarchical porous chromium niobium oxide (Cr0.5Nb24.5O62) microspheres prepared by a facile one-step solvothermal method. The as-prepared Cr0.5Nb24.5O62 microspheres present 3D hierarchical porous structure consisting of cross-linked nanoparticles, high electronic conductivity and large specific surface area. Accordingly, the Cr0.5Nb24.5O62 microspheres show noticeable lithium ion storage performance with superior high-rate capability (199 mAh g-1 at 20C) and good cycling stability with a capacity retention of 95% over 1000 cycles, much better than the bulk Cr0.5Nb24.5O62 and TiNb24O62 counterparts. Our work demonstrates a new high-rate electrode material for high-power energy storage.

Construction of 1T-MoSe2 /TiC@C Branch-Core Arrays as Advanced Anodes for Enhanced Sodium Ion Storage.

The use of active sites and reaction kinetics of MoSe2 anodes for sodium ion batteries (SIBs) are highly related to the phase components (1T and 2H phases) and electrode architecture. This study concerns the design and fabrication of wrinkled 1T-MoSe2 nanoflakes anchored on highly conductive TiC@C nanorods to form 1T-MoSe2 /TiC@C branch-core arrays by a powerful chemical vapor deposition (CVD)-solvothermal method. The 1T-MoSe2 branch can be easily transformed into its 2H-MoSe2 counterpart after a facile annealing process. In comparison to 2H-MoSe2 , 1T-MoSe2 has larger interlayer spacing and higher electronic conductivity, which are beneficial for the acceleration of reaction kinetics and capacity improvement. In addition, direct growth of 1T-MoSe2 nanoflakes on the TiC@C skeleton not only enhance the electrical conductivity, but also contribute to reinforced structural stability. Accordingly, 1T-MoSe2 /TiC@C branch-core arrays are demonstrated with higher capacity and better rate performance (184 mAh g-1 at 10 A g-1 ) and impressive durability over 500 cycles with a capacity retention of approximately 91.8 %. This phase modulation plus branch-core design provides a general method for the synthesis of other high-performance electrode materials for application in electrochemical energy storage.

Ti3+ Self-Doped Li4 Ti5 O12 Anchored on N-Doped Carbon Nanofiber Arrays for Ultrafast Lithium-Ion Storage.

Omnibearing acceleration of charge/ion transfer in Li4 Ti5 O12 (LTO) electrodes is of great significance to achieve advanced high-rate anodes in lithium-ion batteries. Here, a synergistic combination of hydrogenated LTO nanoparticles (H-LTO) and N-doped carbon fibers (NCFs) prepared by an electrodeposition-atomic layer deposition method is reported. Binder-free conductive NCFs skeletons are used as strong support for H-LTO, in which Ti3+ is self-doped along with oxygen vacancies in LTO lattice to realize enhanced intrinsic conductivity. Positive advantages including large surface area, boosted conductivity, and structural stability are obtained in the designed H-LTO@NCF electrode, which is demonstrated with preeminent high-rate capability (128 mAh g-1 at 50 C) and long cycling life up to 10 000 cycles. The full battery assembled by H-LTO@NCFs anode and LiFePO4 cathode also exhibits outstanding electrochemical performance revealing an encouraging application prospect. This work further demonstrates the effectiveness of self-doping of metal ions on reinforcing the high-rate charge/discharge capability of batteries.

Defect Promoted Capacity and Durability of N-MnO2- x Branch Arrays via Low-Temperature NH3 Treatment for Advanced Aqueous Zinc Ion Batteries.

Defect engineering (doping and vacancy) has emerged as a positive strategy to boost the intrinsic electrochemical reactivity and structural stability of MnO2 -based cathodes of rechargeable aqueous zinc ion batteries (RAZIBs). Currently, there is no report on the nonmetal element doped MnO2 cathode with concomitant oxygen vacancies, because of its low thermal stability with easy phase transformation from MnO2 to Mn3 O4 (≥300 °C). Herein, for the first time, novel N-doped MnO2- x (N-MnO2- x ) branch arrays with abundant oxygen vacancies fabricated by a facile low-temperature (200 °C) NH3 treatment technology are reported. Meanwhile, to further enhance the high-rate capability, highly conductive TiC/C nanorods are used as the core support for a N-MnO2- x branch, forming high-quality N-MnO2- x @TiC/C core/branch arrays. The introduced N dopants and oxygen vacancies in MnO2 are demonstrated by synchrotron radiation technology. By virtue of an integrated conductive framework, enhanced electron density, and increased surface capacitive contribution, the designed N-MnO2- x @TiC/C arrays are endowed with faster reaction kinetics, higher capacity (285 mAh g-1 at 0.2 A g-1 ) and better long-term cycles (85.7% retention after 1000 cycles at 1 A g-1 ) than other MnO2 -based counterparts (55.6%). The low-temperature defect engineering sheds light on construction of advanced cathodes for aqueous RAZIBs.

Synergistic Doping and Intercalation: Realizing Deep Phase Modulation on MoS2 Arrays for High-Efficiency Hydrogen Evolution Reaction.

A synergistic N doping plus PO4 3- intercalation strategy is used to induce high conversion (ca. 41 %) of 2H-MoS2 into 1T-MoS2 , which is much higher than single N doping (ca. 28 %) or single PO4 3- intercalation (ca. 10 %). A scattering mechanism is proposed to illustrate the synergistic phase transformation from the 2H to the 1T phase, which was confirmed by synchrotron radiation and spherical aberration TEM. To further enhance reaction kinetics, the designed (N,PO4 3- )-MoS2 nanosheets are combined with conductive vertical graphene (VG) skeleton forming binder-free arrays for high-efficiency hydrogen evolution reaction (HER). Owing to the decreased band gap, lower d-band center, and smaller hydrogen adsorption/desorption energy, the designed (N,PO4 3- )-MoS2 /VG electrode shows excellent HER performance with a lower Tafel slope and overpotential than N-MoS2 /VG, PO4 3- -MoS2 /VG counterparts, and other Mo-base catalysts in the literature.

Bifunctional NiFe layered double hydroxide@Ni3S2 heterostructure as efficient electrocatalyst for overall water splitting.

The tailored construction of non-noble metal bifunctional electrocatalysts for high-efficiency oxygen/hydrogen evolution reactions (OER/HER) is vital for the development of electrochemical energy conversion. Herein, we report a powerful combined wet chemical method to fabricate a novel binder-free NiFe layered double hydroxide@Ni3S2 (NiFe LDH@Ni3S2) heterostructure as an efficient bifunctional electrocatalyst for overall water splitting. The hydrothermal-synthesized NiFe LDH nanosheets are uniformly coated on the Ni3S2 nanosheet skeleton forming 3D porous heterostructure arrays. By virtue of its synergistic advantages, including its binder-free characteristics, increased catalysis sites and structural stability, the as-obtained NiFe LDH@Ni3S2/NF electrode exhibits low overpotentials of 184 and 271 mV at 20 mA cm-2 for HER and OER in 1 M KOH, respectively. Notably, a low operation potential of 1.74 V at a current density of 20 mA cm-2 is achieved for overall water splitting with a stable cycling life. In addition, the intimate composite structure and sensitive interface of NiFe LDH@Ni3S2 are responsible for the good electrocatalytic activity with a low Tafel slope, fast reaction kinetics and high stability. The versatile fabrication protocol and heterostructure interface engineering provide a new way to construct other bifunctional and cost-effective electrocatalysts for electrocatalysis.

Biological Metabolism Synthesis of Metal Oxides Nanorods from Bacteria as a Biofactory toward High-Performance Lithium-Ion Battery Anodes.

Increasing awareness toward environmental remediation and renewable energy has led to a vigorous demand for exploring a win-win strategy to realize the eco-efficient conversion of pollutants ("trash") into energy-storage nanomaterials ("treasure"). Inspired by the biological metabolism of bacteria, Acidithiobacillus ferrooxidans (A. ferrooxidans) is successfully exploited as a promising eco-friendly sustainable biofactory for the controllable fabrication of α-Fe2 O3 nanorods via the oxidation of soluble ferrous irons to insoluble ferric substances (Jarosite, KFe3 (SO4 )2 (OH)6 ) and a facile subsequent heat treatment. It is demonstrated that the stable solid electrolyte interphase layers and marvelous cracks in situ formed in biometabolic α-Fe2 O3 nanorods play important roles that not only significantly enhance the structure stability but also facilitate electron and ion transfer. Consequently, these biometabolic α-Fe2 O3 nanorods deliver a superior stable capacity of 673.9 mAh g-1 at 100 mA g-1 over 200 cycles and a remarkable multi-rate capability that observably prevails over the commercial counterpart. It is highly expected that such biological synthesis strategies can shed new light on an emerging field of research interconnecting biotechnology, energy technology, environmental technology, and nanotechnology.

Coupled Biphase (1T-2H)-MoSe2 on Mold Spore Carbon for Advanced Hydrogen Evolution Reaction.

Performance breakthrough of MoSe2 -based hydrogen evolution reaction (HER) electrocatalysts largely relies on sophisticated phase modulation and judicious innovation on conductive matrix/support. In this work the controllable synthesis of phosphate ion (PO43- ) intercalation induced-MoSe2 (P-MoSe2 ) nanosheets on N-doped mold spore carbon (N-MSC) forming P-MoSe2 /N-MSC composite electrocatalysts is realized. Impressively, a novel conductive N-MSC matrix is constructed by a facile mold fermentation method. Furthermore, the phase of MoSe2 can be modulated by a simple phosphorization strategy to realize the conversion from 2H-MoSe2 to 1T-MoSe2 to produce biphase-coexisted (1T-2H)-MoSe2 by PO43- intercalation (namely, P-MoSe2 ), confirmed by synchrotron radiation technology and spherical aberration-corrected TEM (SACTEM). Notably, higher conductivity, lower bandgap and adsorption energy of H+ are verified for the P-MoSe2 /N-MSC with the help of density functional theory (DFT) calculation. Benefiting from these unique advantages, the P-MoSe2 /N-MSC composites show superior HER performance with a low Tafel slope (≈51 mV dec-1 ) and overpotential (≈126 mV at 10 mA cm-1 ) and excellent electrochemical stability, better than 2H-MoSe2 /N-MSC and MoSe2 /carbon nanosphere (MoSe2 /CNS) counterparts. This work demonstrates a new kind of carbon material via biological cultivation, and simultaneously unravels the phase transformation mechanism of MoSe2 by PO43- intercalation.

ZnO Porous Nanosheets with Partial Surface Modification for Enhanced Charges Separation and High Photocatalytic Activity Under Solar Irradiation.

ZnO porous nanosheets (PNSs) with partial surface modification were fabricated by means of depositing amorphous BiVO4 on basic zinc carbonate nanosheets followed by calcining at 500 °C. At low levels of anchored amorphous BiVO4, the surface of ZnO PNSs was partially evolved into Bi3.9Zn0.4V1.7O10.5 (BZVO). The measurements for photocurrent and photoluminescence demonstrate that partial-surface BZVO-modified ZnO PNSs (ZB_0.01) could significantly inhibit the recombination of photoinduced carriers. This should be ascribable to the driving from surface potential difference produced by non-junction part and vertical p-n BZVO/ZnO junction part on the surface of ZB_0.01. Furthermore, the photocatalytic efficiency in degradation of reactive brilliant red for ZB_0.01 under weak solar irradiation is about 8 times higher than that under strong visible-light illumination. The discussion regarding reasons for this enhancement demonstrates that each component in photocatalysts having rational valence-band maximum and conduction-band minimum energy levels is essential to obtain high-activity sunlight-driven catalysts.