Improved Plasmonic Hot‑Electron Capture in Au Nanoparticle/Polymeric Carbon Nitride by Pt Single Atoms for Broad‑Spectrum Photocatalytic H_(2)Evolution

ABSTRACT Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a“holy grail”for researchers,but is still a challenging issue.Herein,based on the common polymeric carbon nitride(PCN),a hybrid co-catalysts system comprising plasmonic Au nanoparticles(NPs)and atomically dispersed Pt single atoms(PtSAs)with different functions was constructed to address this challenge.For the dual co-catalysts decorated PCN(PtSAs–Au_(2.5)/PCN),the PCN is photoexcited to generate electrons under UV and short-wavelength visible light,and the synergetic Au NPs and PtSAs not only accelerate charge separation and transfer though Schottky junctions and metal-support bond but also act as the co-catalysts for H_(2) evolution.Furthermore,the Au NPs absorb long-wavelength visible light owing to its localized surface plasmon resonance,and the adjacent PtSAs trap the plasmonic hot-electrons for H_(2) evolution via direct electron transfer effect.Consequently,the PtSAs–Au_(2.5)/PCN exhibits excellent broad-spectrum photocatalytic H_(2) evolution activity with the H_(2) evolution rate of 8.8 mmol g^(−1) h^(−1) at 420 nm and 264μmol g^(−1) h^(−1) at 550 nm,much higher than that of Au_(2.5)/PCN and PtSAs–PCN,respectively.This work provides a new strategy to design broad-spectrum photocatalysts for energy conversion reaction.

Construction of LSPR-enhanced 0D/2D CdS/MoO3‒x S-scheme heterojunctions for visible-light-driven photocatalytic H2 evolution

Plasmonic nonmetal semiconductors with localized surface plasmon resonance(LSPR)effects possess extended light-response ranges and can act as highly efficient H2 generation photocatalysts.Herein,an LSPR-enhanced 0D/2D CdS/MoO3‒x heterojunction has been synthesized by the growth of 0D CdS nanoparticles on 2D plasmonic MoO3‒x elliptical nanosheets via a simple coprecipitation method.Taking advantage of the LSPR effect of the MoO3‒x elliptical nanosheets,the light absorption of the CdS/MoO3‒x heterojunction was extended from 600 nm to the near-infrared region(1400 nm).Furthermore,the introduction of 2D plasmonic MoO3‒x elliptical nanosheets not only provided a platform for the growth of CdS nanoparticles,but also contributed to the construction of an LSPR-enhanced S-scheme structure due to the interface between the MoO3‒x and CdS,accelerating the separation of light-induced electrons and holes.Therefore,the CdS/MoO3‒x heterojunction exhibited higher photocatalytic H2 generation activity than pristine CdS under visible light irradiation,including under 420,450,550,and 650 nm monochromic light,as well as improved photo-corrosion performance.

Prolonging charge-separation states by doping lanthanide-ions into {001}/{101} facets-coexposed TiO_2 nanosheets for enhancing photocatalytic H_2 evolution

Ultrathin TiO2 nanosheets with coexposed {001}/{101} facets have attracted considerable attention because of their high photocatalytic activity. However, the charge-separated states in the TiO2 nanosheets must be extended to further enhance their photocatalytic activity for H2 evolution. Herein, we present a successful attempt to selectively dope lanthanide ions into the {101} facets of ultrathin TiO2 nanosheets with coexposed {001}/{101} facets through a facile one-step solvothermal method. The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO2 nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra. Upon simulated sunlight irradiation, we observed a 4.2-fold enhancement in the photocatalytic H2 evolution activity of optimal Yb3+-doped TiO2 nanosheets compared to that of their undoped counterparts. Furthermore, when Pt nanoparticles were used as cocatalysts to reduce the H2 overpotential in this system, the photocatalytic activity enhancement factor increased to 8.5. By combining these results with those of control experiments, we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H2 evolution activity of lanthanide-doped TiO2 nanosheets with coexposed {001}/{101} facets.

Highly efficient visible-light photocatalytic H2 evolution over 2D–2D Cd S/Cu7S4 layered heterojunctions

Converting solar energy into clean and sustainable chemical fuels is a promising strategy for exploiting renewable energy.The application of photocatalytic water splitting technology in hydrogen production is important for sustainable energy development and environmental protection.In this study,for the first time,2D Cu7S4 co-catalysts were coupled on the surface of a CdS nanosheet photocatalyst by a one-step ultrasonic-assisted electrostatic self-assembly method at room temperature.The as-fabricated 2D^-2D CdS/Cu7S4 layered heterojunctions were demonstrated to be advanced composite photocatalysts that enhance the water splitting efficiency toward hydrogen production.The highest hydrogen evolution rate of the 2D^-2D CdS/2%Cu7S4 binary heterojunction photocatalyst was up to 27.8 mmol g^-1 h^-1 under visible light irradiation,with an apparent quantum efficiency of 14.7%at 420 nm,which was almost 10.69 times and 2.65 times higher than those of pure CdS nanosheets(2.6 mmol g^-1 h^-1)and CdS-2%CuS(10.5 mmol g^-1 h^-1),respectively.The establishment of the CdS/Cu7S4 binary-layered heterojunction could not only enhance the separation of photogenerated electron-hole(e--h+)pairs,improve the transfer of photo-excited electrons,and prolong the life-span of photo-generated electrons,but also enhance the light absorption and hydrogen-evolution kinetics.All these factors are important for the enhancement of the photocatalytic activity.Expectedly,the 2D^-2D interface coupling strategy based on CdS NSs can be extensively exploited to improve the hydrogen-evolution activity over various kinds of conventional semiconductor NSs.

Ni nanoparticles as electron-transfer mediators and NiS_x as interfacial active sites for coordinative enhancement of H_2-evolution performance of TiO_2

The development of efficient photocatalytic H2-evolution materials requires both rapid electron transfer and an effective interfacial catalysis reaction for H2 production. In addition to the well-known noble metals, low-cost and earth-abundant non-noble metals can also act as electron- transfer mediators to modify photocatalysts. However, as almost all non-noble metals lack the interfacial catalytic active sites required for the H2-evolution reaction, the enhancement of the photocatalytic performance is limited. Therefore, the development of new interfacial active sites on metal-modified photocatalysts is of considerable importance. In this study, to enhance the photocatalytic evolution of H2 by Ni-modified TiO2, the formation of NiSx as interfacial active sites was promoted on the surface of Ni nanoparticles. Specifically, the co-modified TiO2/Ni-NiSx photocatalysts were prepared via a two-step process involving the photoinduced deposition of Ni on the TiO2 surface and the subsequent formation of NiSx on the Ni surface by a hydrothermal reaction method. It was found that the TiO2/Ni-NiSx photocatalysts exhibited enhanced photocatalytic H2-evolution activity. In particular, TiO2/Ni-NiSx(30%) showed the highest photocatalytic rate (223.74 μmol h.1), which was greater than those of TiO2, TiO2/Ni, and TiO2/NiSx by factors of 22.2, 8.0, and 2.2, respectively. The improved H2-evolution performance of TiO2/Ni-NiSx could be attributed to the excellent synergistic effect of Ni and NiSx, where Ni nanoparticles function as effective mediators to transfer electrons from the TiO2 surface and NiSx serves as interfacial active sites to capture H+ ions from solution and promote the interfacial H2-evolution reaction. The synergistic effect of the non-noble metal cocatalyst and the interfacial active sites may provide new insights for the design of highly efficient photocatalytic materials.

Novel PtPd alloy nanoparticle-decorated g-C_3N_4 nanosheets with enhanced photocatalytic activity for H_2 evolution under visible light irradiation

PtPd bimetallic alloy nanoparticle (NP)-modified graphitic carbon nitride (g-C3N4) nanosheet photocatalysts were synthesized via chemical deposition precipitation. Characterization of the photocatalytic H2 evolution of the g-C3N4 nanosheets shows that it was significantly enhanced when PtPd alloy NPs were introduced as a co-catalyst. The 0.2 wt% PtPd/g-C3N4 composite photocatalyst gave a maximum H2 production rate of 1600.8 μmol g^–1 h^–1. Furthermore, when K2HPO4 was added to the reaction system, the H2 production rate increased to 2885.0 μmol g^–1 h^–1. The PtPd/g-C3N4 photocatalyst showed satisfactory photocatalytic stability and was able to maintain most of its photocatalytic activity after four experimental photocatalytic cycles. In addition, a possible mechanism for the enhanced photocatalytic activity was proposed and verified by various photoelectric techniques. These results demonstrate that the synergistic effect between PtPd and g-C3N4 helps to greatly improve the photocatalytic activity of the composite photocatalyst.

Constructing low-cost Ni3C/twin-crystal Zn0.5Cd0.5S heterojunction/homojunction nanohybrids for efficient photocatalytic H2 evolution

The development of low-cost semiconductor photocatalysts for highly efficient and durable photocatalytic H2 evolution under visible light is very challenging.In this study,we combine low-cost metallic Ni3C cocatalysts with twin nanocrystal Zn0.5Cd0.5S(ZCS)solid solution homojunctions for an efficient visible-light-driven H2 production by a simple approach.As-synthesized Zn0.5Cd0.5S-1%Ni3C(ZCS-1)heterojunction/homojunction nanohybrid exhibited the highest photocatalytic H2-evolution rate of 783μmol h‒1 under visible light,which is 2.88 times higher than that of pristine twin nanocrystal ZCS solid solution.The apparent quantum efficiencies of ZCS and ZCS-1 are measured to be 6.13%and 19.25%at 420 nm,respectively.Specifically,the homojunctions between the zinc blende and wurtzite segments in twin nanocrystal ZCS solid solution can significantly improve the light absorption and separation of photogenerated electron-hole pairs.Furthermore,the heterojunction between ZCS and metallic Ni3C NP cocatalysts can efficiently trap excited electrons from ZCS solid solution and enhance the H2-evolution kinetics at the surface for improving catalytic activity.This study demonstrates a unique one-step strategy for constructing heterojunction/homojunction hybrid nanostructures for a more efficient photocatalytic H2 evolution compared to other noble metal photocatalytic systems.

In situ synthesis of a nickel boron oxide/graphdiyne hybrid for enhanced photo/electrocatalytic H_(2) evolution

Developing highly active catalysts for photo/electrocatalytic water splitting is an attractive strategy to produce H2 as a renewable energy source.In this study,a new nickel boron oxide/graphdiyne(NiBi/GDY)hybrid catalyst was prepared by a facile synthetic approach.Benefitting from the strong electron donating ability of graphdiyne,NiBi/GDY showed an optimized electronic structure containing lower valence nickel atoms and demonstrated improved catalytic performance.As expected,NiBi/GDY displayed a high photocatalytic H2 evolution rate of 4.54 mmol g^(-1)h^(-1),2.9 and 4.5 times higher than those of NiBi/graphene and NiBi,respectively.NiBi/GDY also displayed outstanding electrocatalytic H2 evolution activity in 1.0 M KOH solution,with a current density of 400 mA/cm^(2)at an overpotential of 478.0 mV,which is lower than that of commercial Pt/C(505.3 mV@400 mA/cm^(2)).This work demonstrates that GDY is an ideal support for the development of highly active catalysts for photo/electrocatalytic H2 evolution.

Dual transfer channels of photo-carriers in 2D/2D/2D sandwich-like ZnIn2S4/g-C_(3)N_(4)/Ti_(3)C_(2) MXene S-scheme/Schottky heterojunction for boosting photocatalytic H2 evolution

Construction of multi-channels of photo-carrier migration in photocatalysts is favor to boost conversion efficiency of solar energy by promoting the charge separation and transfer.Herein,a ternary ZnIn_(2)S_(4)/g-C_(3)N_(4)/Ti_(3)C_(2) MXene hybrid composed of S-scheme junction integrated Schottky-junction was fabricated using a simple hydrothermal approach.All the components(g-C_(3)N_(4),ZnIn_(2)S_(4) and Ti_(3)C_(2) MXene)demonstrated two-dimensional(2D)nanosheets structure,leading to the formation of a 2D/2D/2D sandwich-like structure with intimate large interface for carrier migration.Furthermore,the photogenerated carriers on the g-C_(3)N_(4) possessed dual transfer channels,including one route in S-scheme transfer mode between the g-C_(3)N_(4) and ZnIn_(2)S_(4) and the other route in Schottky-junction between g-C_(3)N_(4) and Ti_(3)C_(2) MXene.Consequently,a highly efficient carrier separation and transport was realized in the ZnIn_(2)S_(4)/g-C_(3)N_(4)/Ti_(3)C_(2) MXene heterojunction.This ternary sample exhibited wide light response from 200 to 1400 nm and excellent photocatalytic H_(2) evolution of 2452.1μmol∙g^(–1)∙h^(–1),which was 200,3,1.5 and 1.6 times of g-C_(3)N_(4),ZnIn_(2)S_(4),ZnIn_(2)S_(4)/Ti_(3)C_(2) MXene and g-C_(3)N_(4)/ZnIn_(2)S_(4) binary composites.This work offers a paradigm for the rational construction of multi-electron pathways to regulate the charge separation and migration via the introduction of dual-junctions in catalytic system.

Two Dimension C_3N_4/MoS_2 Nanocomposites with Enhanced Photocatalytic Hydrogen Evolution under Visible Light Irradiation

MoS_2-decorated C_3N_4(C_3N_4/MoS_2) nanosheets hybrid photocatalysts were prepared by a simple sonication-impregnation method. Face-to-face lamellar heterojunctions were well established between two dimension(2D) C_3N_4 and MoS_2 nanosheets. The effects of MoS_2 content on the light absorption, charge transfer and photocatalytic activity of the hybrid samples were investigated. Characterization results show that MoS_2 nanosheets are well anchored on the face of C_3N_4 nanosheets and the composites have well dispersed layered morphology. After loading with MoS_2, the light absorption of composites was much improved, especially in visible-light region. The photocatalytic activities of C_3N_4/MoS_2 samples were evaluated based on the H_2 evolution under visible light irradiation(λ > 400 nm). When the loading amount of MoS_2 was increased to 5 wt%, the highest H_2 evolution rate(274 μmol·g^(-1)·h^(-1)) was obtained. Compared with samples obtained from direct impregnation method, sonication pretreatment is favorable for the formation of 2D layered heterojuctions and thus improve the photocatalytic activity. Slightly deactivation of C_3N_4/MoS_2 composites could be observed when recycled due to the mild photocorrosion of MoS_2. Based on the band alignments of C_3N_4 and MoS_2, a possible photocatalytic mechanism was discussed, where MoS_2 could efficiently promote the separation of the photogenerated carriers of C_3N_4.

The Evolution of IR Spectra of H_2 Adsorbed on ZrO_2 with Changing Temperature（298－723K）

I.r.bands at 1559.0, 1441 .0, 1378 .9, 13603, 1031. 1,981 .4 and 947.3 cm -1 due tovarious types of dissociative adsorption of H2 over ZrO2 with changing temperatore wereobserved by in situ FT-IR spectroscopy.

High Efficient Photocatalytic Degradation of 3,7-Bis(Dimethylamino)-Phenothiazin-5-Ium Chloride Dye and Kinetics of H2 Evolution of N2H4H2O by Synthesized CdS/NiS Nanocomposite by Electrochemical Method

CdS/NiS nanocomposites were synthesized by electrochemical method. Ni and Cd is one of the important II-VI semiconducting materials with a direct band gap of 3.26 eV which finds applications in electrical conductivity and photo-catalysis. The synthesized nanocomposites were characterized by BET, UV-VIS, XRD, FE-SEM (EDAX) techniques. X-Ray diffraction (XRD) reveals crystallite size to be 23.22 nm which was calculated using Williamson-Hall (W-H) plot method. The energy of the band gap for CdS/NiS could be thus estimated to be 3.26 eV. The photocatalytic activity of the sample was evaluated by the degradation of textile dye methylene Blue (MB) in aqueous solutions under UV radiation. Hydrogen energy is regarded as a promising alternative in terms of energy conversion and storage. Hydrogen Evolution Reaction (HER) was carried out in both visible light and UV light by using Hydrazine (N2H4H2O) in the presence of CdS/NiS nanocomposite. The synthesized photocatalyst shows applicable performance for kinetics of Hydrogen Evolution Reaction (HER) in Visible light and UV light. The decomposition of hydrazine (N2H4H2O) proceeded rapidly to generate free hydrogen rich gas through OH radical contact with CdS/NiS nanocomposite at room temperature. The rate of HER is limited by either proton adsorption onto an active site or evolution of formed hydrogen from the surface. A high Tafel slope is indicative of proton adsorption as the rate limiting step, while a lower Tafel slope (20 - 45 mV) indicates that the evolution of molecules hydrogen from the catalyst is rate limiting. In the present case the Tafel slopes for visible light 23.5 mV and 42.5 mV for UV light. Blank experiments show poor activity for HER i.e. 10.1 - 13.5 mV.

CdS/ZnS/ZnO ternary heterostructure nanofibers fabricated by electrospinning for excellent photocatalytic hydrogen evolution without co-catalyst

In recent years,ternary heterostructures(HSs)composed of three semiconductors have attracted significant attention because of the effective separation and transfer of photogenerated electrons and holes in these materials.In this work,new ternary Cd S/Zn S/Zn O(CZZ)HSs with one-dimensional(1D)nanofiber morphology have been successfully fabricated for the first time by a series of processes:electrospinning Zn O nanofibers,sulfurizing Zn O in situ to form Zn S/Zn O binary HSs,and depositing Cd S quantum dots in situ on the Zn S/Zn O HSs.Benefiting from the efficient separation and transfer of photoinduced charge carriers,the optimized CZZ ternary HSs exhibit a hydrogen evolution rate of 51.45 mmol h^-1 g^-1(quantum efficiency:26.88%at 420 nm)without any co-catalyst,which is 93.54 and 2.28 times higher than those exhibited by pristine Zn O and Zn S/Zn O binary HSs,respectively,under the same conditions.Furthermore,the rate of hydrogen evolution over the 1D CZZ nanofibers is significantly higher than that over 2D CZZ nanosheets(27.25 mmol h^-1 g^-1,in the presence of a Pt co-catalyst)prepared by the same sulfurization and deposition procedures.This can be ascribed to the significantly smaller geometric sizes of 1D nanofibers compared to those of 2D nanosheets,resulting in effectively suppressed recombination of photogenerated charge carriers and promotion of photocatalytic H2 evolution performance.

C-I codoped porous g-C_3N_4 for superior photocatalytic hydrogen evolution

Porous C‐I codoped carbon nitride materials were synthesized by in‐situ codoping with iodized ionic liquid followed by post‐thermal treatment in air.The effects of doping content of C‐I codoping with different amounts of ionic liquid on the structural,optical and photocatalytic properties of the samples were investigated.Characterization results show that more compact interlayer sacking can be achieved by post‐thermal treatment.Combined with C‐I codoping by insertion of ionic liquids,much enlarged surface area but optimized sp2 conjugated heterocyclic structure can be found in the catalysts.Optical and energy band analysis results evidence that the light absorptions especially in visible light region are significantly improved.Although the band gap of porous C‐I codoped samples enlarge because of the generation of porous,the negatively shifted conduction band position thermodynamically supplies stronger motivation for water reduction.Photoelectricity tests reveal that the photo‐induced electron density was increased after C‐I codoping modification.Also,the recombination rate of electron‐hole pairs is remarkably inhibited.The catalysts with moderate C‐I codoing content perform sharply enhanced photocatalytic H2 evolution activity under visible light irradiation.A H2 evolution rate of 168.2μmol/h was achieved and it was more than 9.8 times higher than pristine carbon nitride.This study demonstrates a novel non‐metal doping strategy for synthesis and optimization of polymer semiconductor with gratifying photocatalytic H2 evolution performance from water hydrolysis.

The evolution,pathogenicity and transmissibility of quadruple reassortant H1N2 swine influenza virus in China:A potential threat to public health

Swine are regarded as“intermediate hosts”or“mixing vessels”of influenza viruses,capable of generating strains with pandemic potential.From 2020 to 2021,we conducted surveillance on swine H1N2 influenza(swH1N2)viruses in swine farms located in Guangdong,Yunnan,and Guizhou provinces in southern China,as well as Henan and Shandong provinces in northern China.We systematically analyzed the evolution and pathogenicity of swH1N2 isolates,and characterized their replication and transmission abilities.The isolated viruses are quadruple reassortant H1N2 viruses containing genes from pdm/09 H1N1(PB2,PB1,PA and NP genes),triple-reassortant swine(NS gene),Eurasian Avian-like(HA and M genes),and recent human H3N2(NA gene)lineages.The NA,PB2,and NP of SW/188/20 and SW/198/20 show high gene similarities to A/Guangdong/Yue Fang277/2017(H3N2).The HA gene of swH1N2 exhibits a high evolutionary rate.The five swH1N2 isolates replicate efficiently in human,canine,and swine cells,as well as in the turbinate,trachea,and lungs of mice.A/swine/Shandong/198/2020 strain efficiently replicates in the respiratory tract of pigs and effectively transmitted among them.Collectively,these current swH1N2 viruses possess zoonotic potential,highlighting the need for strengthened surveillance of swH1N2 viruses.

差分进化改进微电网负荷频率混合H2/H∞鲁棒控制

针对外部扰动及系统参数摄动引起微电网负荷频率波动问题,设计了混合H2/H∞鲁棒控制器对系统负荷频率进行控制。建立了包含电池的柴油发电机组二次频率控制模型,引入低通滤波器,使电池对系统高频扰动信号具有较好的抑制能力。以误差平方的积分最小作为系统的目标函数,在综合H_2范数表征的系统性能和H∞范数表征的鲁棒性能下,设计具有多目标约束条件的混合H2/H∞鲁棒控制器。采用差分进化算法对控制器加权函数参数进行寻优,使控制器在满足约束条件下达到最优。仿真实验结果表明所提出方法在满足系统鲁棒性能的基础上,同时具备较好的控制输出,保证微电网频率在外部功率扰动和系统参数摄动情况下具有较好的动态性能。

Sulfurization synthesis and photocatalytic activity of oxysulfide La_3NbS_2O_5

The oxysulfide La3NbS2O5 was synthesized by sulfurization using H2S and characterized by X-ray diffraction （XRD）, UV-Vis diffuse reflectance spectroscopy （DRS） and field emission scanning electron microscopy （FE-SEM）. The relationship between the sulfurization conditions and the photocatalytic activities for H2 evolution was investigated. Sulfurization method allowed for synthesis of La3NbS2O5 at much lower temperatures and significantly shortened reaction time of 1 h compared with conventional solid-state techniques. The particle morphologies were regular platelike with sizes of 0.1-0.6μm and smooth surfaces. The highest activity for H2 evolution was obtained at 1073 K for 1 h, which was about 1.83 times that of La3NbS2O5 prepared by solid-state method.

One-pot hydrothermal synthesis of willow branch-shaped MoS_2/CdS heterojunctions for photocatalytic H_2 production under visible light irradiation

Willow branch-shaped MoS2/CdS heterojunctions are successfully synthesized for the first time by a facile one-pot hydrothermal method. The as-prepared samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption measurements, diffuse reflectance spectroscopy, and photoelectrochemical and photoluminescence spectroscopy tests. The photocatalytic hydrogen evolution activities of the samples were evaluated under visible light irradiation. The resulting MoS2/CdS heterojunctions exhibit a much improved photocatalytic hydrogen evolution activity than that obtained with CdS and MoS2. In particular, the optimized MC-5 (5 at.% MoS2/CdS) photocatalyst achieved the highest hydrogen production rate of 250.8 μmol h–1, which is 28 times higher than that of pristine CdS. The apparent quantum efficiency (AQE) at 420 nm was 3.66%. Further detailed characterizations revealed that the enhanced photocatalytic activity of the MoS2/CdS heterojunctions could be attributed to the efficient transfer and separation of photogenerated charge carriers resulting from the core-shell structure and the close contact between MoS2 nanosheets and CdS single-crystal nanorods, as well as to increased visible light absorption. A tentative mechanism for photocatalytic H2 evolution by MoS2/CdS heterojunctions was proposed. This work will open up new opportunities for developing more efficient photocatalysts for water splitting.

Unraveling the reaction mechanism of low dose Mn dopant in Ni(OH)_(2) supercapacitor electrode

Mn doping is deemed as a promising strategy to improve the electrochemical performance of the a-Ni(OH)_(2)battery-type supercapacitor electrode.However,the internal structure evolution,the pathways and the dynamics of the proton/intercalated anion migration,as well as the functioning mechanism of Mn dopant to stabilize the layered structure during cycles remain unclear.Here,we unveil that irreversible oxidization of Mn^(3+)at the initial CV cycles,which will remain as Mn^(4+)in the NiO_(2)slabs after the first oxidization to effectively suppress the phase transformation fromα-Ni(OH)_(2)/γ-NiOOH toβ-Ni(OH)_(2)/β-NiOOH and further maintain the structural integrity of electrode.With a synergistic combination of theoretical calculations and various structural probes including XRD and^(2)H MAS solid state NMR,we decode the structure evolution and dynamics in the initial CV(cyclic voltammetry)cycles,including the absorption/desorption of hydrogen containing species,migration of intercalated anions/water molecules and the change of interlayer space.This present work elucidates a close relationship between doping chemistry and structural reliability,paving a novel way of reengineering supercapacitor electrode materials.

Immobilization of metal-organic molecular cage on g-C3N4 semiconductor for enhancement of photocatalytic H2 generation

A new compound based on immobilizing of Pd6(RuL3)8(BF4)28 (L=2-(pyridin-3-yl)-1H-imidazo [4,5-f][1,10]-phenanthroline) cage (MOC-16) on g-C3N4 was synthesized. Infrared spectrum and powder X-ray diffraction were used to characterize structure of hybrid MOC-16/g-C3N4, as well as UV-vis absorption spectrum and X-ray photoelectron spectroscopy were carried out to unveil photocatalytic mechanism. With the introduction of MOC-16, the absorption edge of MOC-16/g-C3N4 in UV-vis spectrum extended apparently to long-wavelength region compared with pristine g-C3N4. H2 evolution yielded with MOC-16/g-C3N4 in aqueous solution containing TEOA was much higher than that with RuL3/g-C3N4, Pd/RuL3/g-C3N4 and mixture of MOC-16 and g-C3N4, showing that the octahedral cage structure with high-efficient electron transfer and the interface interaction between MOC-16 and g-C3N4 were significant for improvement of H2 evolution.