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Tungsten phosphide (WP) as an excellent hydrogen evolution reactions (HER) catalyst has attracted widespread attention, but its HER activity is low in alkaline media due to high water dissociation barrier. Herein, noble-metal-free cocatalyst WP/WO 3 composite was synthesized by adjusting the P/W molar ratio in the raw material using a simple solid phosphidation reaction. The structure, morphology, composition, and optoelectronic properties of the as-synthesized samples were characterized by XRD, SEM, TEM, XPS, UV–vis DRS, PL techniques, and electrochemical methods. Under visible light irradiation (λ ≥ 420 nm), the photocatalytic HER activities of the as-prepared samples using Eosin-Y (EY) dye as a sensitizer and trimethylamine (TMA) as an electron donor were investigated. The result shows that WP/WO 3 composite as a cocatalyst exhibits excellent photocatalytic HER activity and good stability. The highest apparent quantum yield (AQY) reaches 32.8 %. The presence of amorphous WO 3 in crystalline WP can improve the separation efficiency of photogenerated electrons and holes, reduce HER overpotential, and promote the dissociation of H 2 O in alkaline media. Therefore, the photocatalytic HER activity of WP/WO 3 composite is higher than that of single crystalline WP. [Display omitted] • WP/WO 3 composite was prepared by adjusting the P/W molar ratio in the raw material. • WP/WO 3 composite exhibits high dye-sensitized photocatalytic HER activity. • WO 3 coupling with WP promotes the separation of photocarriers and H 2 O dissociation. • The AQY of 32.8 % at 420 nm is achieved under the optimized conditions. [ABSTRACT FROM AUTHOR]

A series of MoP were synthesized by a facile solid reaction and used as catalysts for H 2 evolution from alkaline HCHO solution. It was found that the as-prepared MoP catalysts exhibited high H 2 evolution activity and stability. The calcination temperature had a great influence on the structure, morphology and H 2 evolution activity of MoP. When the calcination temperature was 400 °C, the MoP-400 exhibited the highest H 2 evolution activity. The concentration of HCHO and reaction temperature in the reaction system also affected the H 2 evolution efficiency. The H 2 evolution performance of MoP was better than or comparable to those of the reported noble metal catalysts. The possible mechanism of H 2 evolution from HCHO was discussed. [Display omitted] • MoP was synthesized and used as catalysts for H 2 evolution from formaldehyde. • The MoP calcined at 400 °C has the highest catalytic activity for H 2 evolution. • The activity of MoP is much higher than Au and Pt, and comparable to Ag and Pd. • The high activity of MoP-400 is due to its more active sites and larger S BET. [ABSTRACT FROM AUTHOR]

Titanium nitride (TiN) film is a remarkable material for a variety of applications ranging from superhard coating to superconducting quantum devices, which can be easily oxidized when it works in the atmosphere. However, the study of its oxidation effect on the crystal and electronic structures of epitaxial TiN films is rare as yet. Here, we coherently synthesize TiN epitaxial films on MgO single crystal substrates via reactive magnetron sputtering and, then, dope oxygen into these films via a controllable oxidation process. The crystal and electronic structures are characterized by high-resolution x-ray diffraction, x-ray photoelectron spectra, and Raman spectra. It is revealed that the crystal structure remains to be of the rocksalt type in these films even with heavy oxygen doping. The data of temperature-dependent electrical transport measurements indicate that the superconducting critical temperature (kinetic inductance) decreases (increases) from 4.6 K (0.672 pH/□) in the pristine TiN film to 3.4 K (1.13 pH/□) in the film with a maximum oxygen doping level. Our work provides a controllable way to tune the superconductivity of TiN films, which enables the flexibility to engineer the resultant performance of TiN-based superconducting quantum devices. [ABSTRACT FROM AUTHOR]

Using non-toxic red phosphorus as the phosphorus source, Ni 2 P was synthesized and in situ loaded on Cd 0.5 Zn 0.5 S photocatalyst by a simple solvothermal method for photocatalytic H 2 evolution under visible light (λ ≥ 420 nm) irradiation. The as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), ultraviolet–visible diffuse reflectance spectra (UV–Vis DRS), Brunauer–Emmett–Teller (BET) surface area measurements and electrochemistry techniques. The photocatalytic hydrogen evolution activity over Cd 0.5 Zn 0.5 S is significantly increased by in situ-loaded Ni 2 P due to the intimate interface contact and efficient charge transfer from Cd 0.5 Zn 0.5 S to Ni 2 P. The 4 wt%Ni 2 P-loaded Cd 0.5 Zn 0.5 S photocatalyst shows five times higher H 2 evolution rate than that of the pristine Cd 0.5 Zn 0.5 S. The highest H 2 evolution rate of 65.6 μmol/h and the apparent quantum yield (AQY) of 29% at 420 nm is achieved under the optimized conditions. The noble metal free Ni 2 P is stable during 20 h photocatalytic reaction. [ABSTRACT FROM AUTHOR]

Element substitution of BaTiO 3 -based compounds has been demonstrated as a powerful way for designing novel electronic materials (such as polar metals and multiferroics). To trigger magnetism into ferroelectric BaTiO 3 , general substituted elements are magnetic transition metals (such as Mn, Fe, and Co). The doping effect of rare-earth elements (such as Dy) in BaTiO 3 -based compounds was barely investigated. Here, we report the coexistence of magnetism and electric polarization in epitaxial Dy 0.5 Ba 0.5 TiO 3 films. The single-crystalline films were synthesized by high-pressure magnetron sputtering. The crystal and electronic structures were characterized by high-resolution x-ray diffraction, x-ray photoemission spectroscopy, and resonant soft x-ray absorption spectroscopy. Room-temperature electric polarization was demonstrated by optical second-harmonic generation. Temperature-dependent magnetic hysteresis loops were measured to reveal the revolution of magnetism on temperature. Surprisingly, it is uncovered that the Curie temperature of electric-polarized Dy 0.5 Ba 0.5 TiO 3 films is around 100 K, far above the critical temperature of non-polarized DyTiO 3 (near 60 K). Our work provides another view to understand the magnetoelectric materials. [ABSTRACT FROM AUTHOR]

A series of ZIS-x [ZIS and x represent the ZnIn 2 S 4 and the addition amount of TEOA (mmol) in the synthesis process, respectively] were synthesized via a hydrothermal method using triethanolamine (TEOA) as a template. The as-synthesized photocatalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Ultraviolet-visible (UV–vis) diffuse reflection spectroscopy and Brunauer–Emmett–Teller (BET) surface area measurement. The effects of TEOA on the crystal structures, morphologies and optical properties of ZIS-x products were investigated. The photocatalytic activity was tested in the reaction of H 2 evolution from aqueous TEOA solution under visible light irradiation (λ ≥ 420 nm). It was found that the activity of ZIS-x synthesized in TEOA solution was higher than that of ZIS-0 synthesized in pure water. This can be attributed to the facts that ZIS-x is composed of single ZnIn 2 S 4 and more TEOA can be adsorbed on ZIS-x surface, which improves the separation of an electron-hole pair. When TEOA was used as an electron donor, it can enhance notably photocatalytic H 2 evolution with its simultaneous degradation. The effect of TEOA concentration on the H 2 evolution rate is consistent with a Langmuir–Hinshelwood kinetic model. The optimal amount of Pt loaded on the photocatalyst is 0.50 wt%, and the optimal pH for photocatalytic H 2 evolution is 13. On the optimal condition, the rate of hydrogen evolution over ZIS-2.0 is 2 times as high as that of ZIS-0 during 20 h irradiation. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoP/g-C 3 N 4 hybrid photocatalyst was prepared in which CoP acts as a noble-metal-free HER cocatalyst. • CoP/g-C 3 N 4 composite exhibits high dye-sensitized photocatalytic HER activity and stability. • Photogenerated electrons can effectively transfer among EY, g-C 3 N 4 and CoP. • The AQY of 56.3% at 420 nm is achieved under the optimized conditions. In this paper, CoP/g-C 3 N 4 composite photocatalysts were prepared, in which CoP was used as a noble-metal-free cocatalyst. Using dye Eosin Y (EY) as the sensitizer and triethanolamine (TMA) as the electron donor, the performance of the photocatalytic H 2 evolution reaction (HER) under visible light (λ ≥ 420 nm) was investigated. When the loading of CoP is 5 wt%, the CoP(5 wt%)/g-C 3 N 4 composite shows the best photocatalytic HER performance, even better than that of Pt(5 wt%)/g-C 3 N 4. The apparent quantum yield (AQY) achieves 56.3% under 420 nm light irradiation, one of the best values reported for noble-metal-free cocatalysts in the dye-sensitized HER system, and the catalyst also exhibits good stability under 36 h of irradiation. The high activity and stability of CoP(5 wt%)/g-C 3 N 4 are the results of efficient electron transfer among photoexcited EY, g-C 3 N 4 and CoP, and the excellent HER activity of CoP. [ABSTRACT FROM AUTHOR]

Nickel species were loaded on titanate nanotubes (TNT) as a hydrogen evolution cocatalyst by an impregnation–calcination method. Nickel chloride, nickel nitrate and nickel acetate were used as the precursors. More Ni 2+ ions intercalate into the interlayer of TNT when nickel chloride is used as the precursor. In the calcination process, the titanate transforms into anatase TiO 2 , and Ni 2+ ions are reduced and doped partly in TiO 2 and titanate. The Ni 2+ ions intercalated into TNT inner can promote the phase transformation, growth of metal Ni particles and the Ni 2+ doping. The formed Ni particles can be oxidized in air to form core/shell Ni@NiO structure. The Ni 2+ doping promotes the formation of oxygen defects and increases the conductivity of TNT. The photocatalytic activity of Eosin Y-sensitized nickel-modified TNT for hydrogen evolution was investigated. The TNT modified with nickel chloride exhibit higher activity, which can be attributed to the higher conductivity and more effective formation of Ni@NiO structure. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we report the obtention of a series of rare earth doped composite Pt/RE/TiO2-CdS (RE=La3+, Eu3+, Er3+, Gd3+) and TiO2-CdS photocatalysts prepared by a simple mechanical mixed method. The photocatalysts properties were studied by means of ultraviolet-visible spectroscopy, photoluminiscence spectra, X-ray diffraction, transmission electron microscopy, specific surface areas and the electrochemistry method. Photocatalytic hydrogen evolution using Na2S/Na2SO3 as electron donor was investigated under visible-light (λ≥420nm) irradiation. The rare earth doping enhances the activities of Pt/RE/TiO2-CdS samples (with 1.0wt% deposited Pt). Under optimum conditions, the activities of La3+, Eu3+, Er3+, Gd3+ doped composite Pt/RE/TiO2-CdS increase by 62.0%, 40.4%, 34.7% and 30.0% respectively, when compared to that of Pt/TiO2-CdS, due to the prevention of electron–hole recombination and the flat-band potential of the conduction of TiO2 shifting negatively by the doping. [Copyright &y& Elsevier]

Abstract: Bi3+ doped Cd0.5Zn0.5S photocatalysts were prepared by a simple hydrothermal method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscope (XPS), energy dispersive X-ray spectroscopy (EDX), BET and UV-Vis absorption spectroscope techniques. When Bi3+ doping content is lower, the doping ions lie at the surface lattice sites, whereas when the doping content is higher, the ions also enter the bulk lattice sites. Their photoactivities were evaluated by hydrogen evolution from aqueous solution containing Na2S and Na2SO3 as a hole scavenger under visible light (λ ≥ 420 nm) irradiation. Bi3+ doping enhances markedly photocatalytic activity. When Bi3+ doping content is 0.10 mole %, the photocatalyst exhibits the highest activity, and the average apparent quantum yield amounts to 9.71% during 30 h irradiation. The possible mechanism was discussed. [Copyright &y& Elsevier]

TiO2 photocatalysts doped with Be2+ were prepared by impregnation and coprecipitation method. The samples were characterized by XRD, XPS and IR. Their activities were evaluated by photocatalytic hydrogen production. It is found that Be2+ can enter into the interstitial site of TiO2 lattice, and the photocatalytic activities depend on doping method. When the doping ions were in the shallow surface, the doping was beneficial; while in the deep bulk, the doping was detrimental. On the optimum conditions, the photocatalytic activity of the doped TiO2 increased by 75% compared to pure TiO2. [Copyright &y& Elsevier]

[Display omitted] Construction of semiconductor heterojunctions which promote the separation and transport of photogenerated carriers is an effective strategy for improving photocatalytic reaction efficiency. Based on the anisotropic electrical conductivity of layered ZnIn 2 S 4 (ZIS) photocatalyst, an efficient heterojunction should be constructed along the layer plane of ZIS, that is, a J type heterojunction. However, achieving controllable synthesis of the oriented heterojunction of ZIS faces challenges. Herein, we develop a facile, cost-effective and spatially-selective cation exchange synthesis approach to construct J type ZnIn 2 S 4 @CdIn 2 S 4 (J-ZIS@CIS) heterojunction using a flower-like hexagonal ZIS as the parent material. The developed synthesis approach can also control crystal structure of the heterojunction component CIS. This work presents a facile and controllable synthesis strategy to construct oriented anisotropic heterojunctions that are otherwise inaccessible. The as-prepared J-ZIS@CIS heterojunction displays a greatly enhanced photocatalytic hydrogen evolution activity with a rate of 183 μmol h−1, 2.77 times higher than that of pristine ZIS. Furthermore, the possible photocatalytic reaction mechanism is presented for the heterojunction. [ABSTRACT FROM AUTHOR]

All carbon-based CG/M − CN rectangular nanotubes have been constructed by a facile molten salt thermal condensation of melamine and glucose. In the molten salt fluid, the glucose is carbonized into graphene-like (CG) nanosheets acting as an electron acceptor, and the melamine thermally condenses into carbon nitride (M − CN) rectangular nanotube acting as an electron donor. The 0.5 wt% CG/M − CN nanotubes display a photocatalytic H 2 evolution rate of 2345 μmol h−1 g−1, which is 1.52 times higher than that of M-CN. Moreover, without loading Pt co-catalyst, the 0.5 wt% CG/M − CN nanotubes show a 12.75 times higher photocatalytic H 2 evolution rate than that of M-CN. It is revealed that the graphene-like CG nanosheets not only can act as an electron acceptor boosting charge carrier separation, but also function as a HER cocatalyst for M-CN. Our work provides a new insight for the development of all carbon-based photocatalysts for energy-related applications. All carbon-based donor-acceptor (D-A) conjugated CG/M − CN rectangular tubular composites with HER cocatalyst free have been constructed through a facile one-step molten salt thermal condensation approach, which exhibits superior photocatalytic hydrogen evolution performance. [Display omitted] • The CG/M − CN composites are developed by a molten salt thermal condensation method. • CG acts as an electron acceptor and cocatalyst for M − CN to drive H 2 evolution. • The D-A conjugated system promotes fast charge carrier transfer in CG/M-CN. • The 0.5 wt% CG/M − CN without cocatalyst shows optimal photocatalytic performance. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4), as an attractive metal-free polymer photocatalyst, has attracted extensive attention in energy and environmental fields in recent years. The photoactivity of bulk g-C3N4 is moderate on account of solid-phase thermal-condensation synthesis. This leads to inadequate light absorption, limited surface area, and easy recombination of charge carriers. The composition and nanostructure of g-C3N4 have been studied extensively. Molten-salt modulation is fascinating because of its "green" credentials and the properties of liquid-phase reaction systems. The review focuses mainly on molten-salt modulation of the composition and structure of g-C3N4 based-photocatalysts. We focus on elemental doping, molecular doping, and defect engineering, as well as control of the crystal structure, multi-dimensional structure, hom/heterostructures for photocatalytic applications. This review provides new insights to develop g-C3N4-based photocatalysts with control of composition and structure by facile molten-salt modulation in energy-conversion and environmental fields. [ABSTRACT FROM AUTHOR]

Crystalline carbon dots (CCDs) embedded in carbon nitride (CN) nanofragments (CCDs-CN) have been developed through facile molten salt treatment. Molten salt treatment not only reconstructs CN layered sheets to form nanofragments, but also promotes the crystallization of CDs-CN. The π-conjugated electric field between CCDs and CN accelerates charge carrier separation for efficient photocatalytic H2 evolution. [ABSTRACT FROM AUTHOR]

Building carbon nitride (CN)-based core shell heterostructures is an effective strategy to enhance the photocatalytic performance and stability by optimize the interface area and protect the CN core, respectively. Moreover, by fabricating the porous structures in core shells can further optimize the light absorption, charge separation, and mass transfer. Herein, we have constructed porous C-PDA–CN–ms core-shell heterostructures through a facile green molten salt (ms) sculpture the polydopamine (PDA) derived carbon (C-PDA) shells with CN core. In which, the C-PDA-CN core-shells arise from in situ polymerization of dopamine (DA) on the surface of melamine to form PDA@melamine coatings followed by thermal polycondensation. The molten salts at high-temperature act as a green fluid immersing in and out of C-PDA-CN core-shells to further produce porous structures. The 1 wt% C-PDA–CN–ms with porous core-shell structures display photocatalytic H 2 evolution rate of 3830 μmol h−1 g−1, which is 20.8 times enhancement of 1 wt% C-PDA-CN core-shells, even 73.6 times higher than that of pristine CN. It reveals that the porous and core-shell heterostructures endow C-PDA–CN–ms enhanced light absorption, various charge transport channels for improved charge carrier separation and transfer, contributing to the superior photocatalytic H 2 evolution performance. Our work opens a new window for the green construction of porous core-shell heterostructures of CN-based photocatalysts. The porous C-PDA–CN–ms core-shells have been developed through a green molten salt sculpture approach, which promotes light absorption and charge carrier transfer for efficient photocatalytic H 2 evolution. [Display omitted] • Porous C-PDA/CN-ms core-shells are constructed by a molten salt sculpture approach. • Molten salt fluid sculpture C-PDA-CN core-shells to produce porous structures. • The porous C-PDA–CN–ms core-shells exhibit superior photocatalyticperformance. • The optimized photocatalytic H 2 evolution rate is 3830 μmol h−1 g−1, with a AQE of 39.6% at 420 nm. • The porous core-shells endow CN improved light absorption and charge separation. [ABSTRACT FROM AUTHOR]

In this work, a noble-metal-free homogeneous system was constructed in one step with Keggin-type polyoxometalate (POM) SiW 12 O 40 4− as a catalyst, Eosin Y as a photosensitizer, and triethanolamine (TEOA) as a sacrificial electron donor for water splitting to produce hydrogen under visible-light irradiation. A two-electron reduced heteropoly blue SiW 12 O 40 6− is produced by photosensitization under visible-light irradiation. The effect of various component concentrations and POMs with different central atoms (PW 12 O 40 3− , GeW 12 O 40 4− , etc.) on hydrogen production was discussed. This simple system made of earth-abundant elements is expected to contribute toward the development of functional and efficient artificial photosynthetic system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni 12 P 5 was in situ anchored on ZnIn 2 S 4 via a solvothermal route. • The intimate interface between Ni 12 P 5 and ZnIn 2 S 4 can promote the charge transfer from ZnIn 2 S 4 to Ni 12 P 5. • ZnIn 2 S 4 loaded with 6 wt% Ni 12 P 5 exhibits the best hydrogen production activity and excellent stability. • The possible photocatalytic mechanism was discussed. It is a great challenge to develop efficient, stable and inexpensive hydrogen evolution reaction (HER) catalysts for photocatalytic water-splitting. In this paper, Ni 12 P 5 (NP) was in situ anchored on the surface of ZnIn 2 S 4 (ZIS) via a solvothermal route with nickel chloride and red phosphorus as ingredients. Using triethanolamine as sacrificial agent, the photocatalytic hydrogen evolution activity of NP/ZIS was studied under visible light irradiation. At the same time, the composition, structure, morphology and photoelectrochemical properties of the as-obtained samples were analyzed through a sequence of characterization techniques. ZIS loaded with 6 wt% NP (6NP/ZIS) exhibits the best hydrogen evolution activity and excellent stability. The H 2 evolution rate of 6NP/ZIS is 5.4 times higher than that of pristine ZIS and well beyond that of the physical mixture (6NP + ZIS) or even that of the optimal Pt/ZIS under the same conditions. The maximal apparent quantum yield (AQY) of 22.7 % at 400 nm is achieved, superior to the most reported performance of ZnIn 2 S 4 -based photocatalysts for HER. The anchor of NP can not only enhance the visible light absorption intensity, but also reduce the HER overpotential. More importantly, the intimate interface between ZIS and NP can promote the separation and migration of photo-excited carriers, thereby enhancing the activity of photocatalytic hydrogen evolution. The possible photocatalytic reaction mechanism was discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A volume OER (VOER) strategy for layered hydroxides was presented. • Phosphate-intercalated Ni(OH) 2 /NiOOH loaded on Ni foam was prepared as a VOER catalyst. • The catalyst displays better OER activity than benchmark RuO 2 and most Ni-based catalysts. • The long-term stability is over 1000 h, much better than other Ni-based OER catalysts. • The role of phosphate intercalation on VOER has been revealed. Layered Ni(OH) 2 /NiOOH hydroxides are effective oxygen evolution reaction (OER) electrocatalysts, but their activities are still inferior to those of benchmark RuO 2 and IrO 2. Notably, the long-term stability becomes a significant challenge. Herein, we present a novel volume OER (VOER) strategy to solve the problems via pre-intercalation of phosphate. Phosphate-intercalated Ni-Ni(OH) 2 /NiOOH electrode was prepared by a two-step electrochemical method. The obtained porous electrode exhibits outstanding OER performance in the alkaline phosphate electrolyte with the overpotentials of 129 and 243 mV at 10 and 100 mA cm−2, respectively, and stability for 1000 h. The exceptional performance is mainly ascribed to effective VOER and elimination of the interlayer-produced protons, because the phosphate-intercalation enhances the interlayer water content, interlayer spacing and proton transport ability, endows the interlayers with proton buffering capacity, and alters the chemical environment of the interlayer Ni-O. The finding provides a strategy to develop highly efficient and stable OER materials and reaction systems for layered transition metal hydroxides. [ABSTRACT FROM AUTHOR]

Condensed π-conjugation C-PAN/MS-CN nanotubes were obtained via a facile polyacrylonitrile (PAN)-confined molten salt (MS) thermal condensation of melamine. Carbonized PAN (C-PAN) nanosheets with a conjugate network structure in the molten salt system acted as partition plates confining the thermal condensation of melamine, which promoted the formation of condensed π-conjugation carbon nitride (CN) for the effective charge carrier separation and photocatalytic H2 evolution. [ABSTRACT FROM AUTHOR]

Si, as a narrow bandgap semiconductor with a broadband absorption for sunlight, is considered to be a very competitive photoelectrode material for solar‐driven photoelectrochemical (PEC) water splitting. However, there are major barriers in construction of efficient and stable Si‐based PEC cell, including low photovoltage, sluggish reaction kinetics, and poor stability in electrolytes. This review focuses on the strategies to solve these issues and summarizes recent progress. The working principles of PEC water splitting are first introduced. Then the strategies for improving Si‐based photoelectrode performances are discussed, including (1) the regulation of Si surface morphology for enhancing light harvesting, (2) band structure engineering strategies to reduce recombination of photogenerated carriers, and (3) modification of protection layers for long stability and loading cocatalysts on Si‐based photoelectrodes for accelerating water splitting. Lastly, we have presented some issues of Si‐based photoelectrode materials, which should be addressed in future research. [ABSTRACT FROM AUTHOR]

• Co(OH) 2 nanosheets with tiny Co nanocrystallines on RGO are transformed from large-particle CoO@Co/RGO in dye-sensitized photocatalytic reaction. • The formed Co(OH) 2 nanosheets on RGO surface act as the effective adsorption of OH– to promote water dissociation. • The exposed tiny Co nanocrystallines on Co(OH) 2 nanosheets provide sufficient adsorption sites for H*. • Co/Co(OH) 2 /RGO cocatalyst shows much improved photocatalytic HER activity than pristine CoO@Co/RGO. It is of huge challenge to develop stable and efficient non-metal based cocatalysts for photocatalytic hydrogen evolution reaction (HER) via dye sensitization. Herein, we demonstrate a composite featuring Co(OH) 2 nanosheets embedded with metal Co nanocrystallines on reduced graphene oxide (Co/Co(OH) 2 /RGO) as a durable cocatalyst, which is obtained from the CoO@Co/RGO composite in dye-sensitized photocatalytic HER process via the dissolution-precipitation reaction of Co element. The large CoO@Co nanoparticles (∼43 nm in diameter) are converted to thin Co(OH) 2 nanosheets, and tiny Co nanocrystalllines are exposed on the surface. As a fresh cocatalyst, Co/Co(OH) 2 /RGO is endowed with favorable adsorption sites of both hydrogen and hydroxyl. Such a phase and structure transformation leads to the high photocatalytic activity (136.1 μmol) of Co/Co(OH) 2 /RGO cocatalyst via dye sensitization, which is 3.7 times as much as that of pristine CoO@Co/RGO (36.7 μmol). The improved HER performance should be highly related to the more effective interfacial electron transfer ability, as reflected by transient absorption decays, and photocurrent test. Moreover, the Co/Co(OH) 2 /RGO cocatalyst shows a remarkable stability of photocatalytic H 2 evolution, as well as the structural and phase stability. This work provides a novel route to develop highly dispersive and efficient non-noble metal based cocatalysts, and a new vision to understand the dynamic structure–activity relationship of the cocatalysts. [ABSTRACT FROM AUTHOR]

Abstract: NiS was loaded on ZnS1−x−0.5y O x (OH) y –ZnO photocatalyst by two methods (depositing NiS on the photocatalyst via impregnation with a NiS sol and via a precipitation reaction). The activity of the NiS-modified photocatalyst for hydrogen evolution from pure water and seawater was investigated using mixed electron donors (sulfide and sulfite). The activity (in pure water-electron donor solution) is dependant of the modification method and loading content of NiS. When Na2S·9H2O and Na2SO3 are added into seawater, a mixture precipitate (Mg(OH)2 and CaSO3) produces. The precipitate is detrimental to the photocatalytic hydrogen evolution over the unmodified ZnS1−x−0.5y O x (OH) y –ZnO. However, for the NiS-modified photocatalyst, the detrimental effect decreases notably. Interestingly, the activity of the modified photocatalyst in seawater-electron donor solution (with the precipitate) is higher than that in the pure water-electron-donor solution (without the precipitate). The possible mechanism was discussed. [Copyright &y& Elsevier]

TiO2 was modified with sulfate and phosphate (denoted as S/TiO2 and P/TiO2) through a simple sulfuric or phosphoric acid treatment. A strong coordination bond forms between sulfate or phosphate and Ti4+ of TiO2. Eosin Y (EY)-sensitized S/TiO2 and P/TiO2 (Pt as a co-catalyst and triethanolamine as a sacrificial electron donor) exhibit enhanced photocatalytic activity for hydrogen evolution under visible light illumination (λ ＞ 420 nm) compared to that of EY-sensitized TiO2. The conduction band (CB) edges of S/TiO2 and P/TiO2 shift toward the negative, and the hydrogen bond interaction between the reduced radical EYṖ–H and S/TiO2 or P/TiO2 is enhanced due to the inducing effect of the bound sulfate and phosphate. Thus, the photocatalytic hydrogen evolution is promoted. The effects of the concentration of the sulfuric or phosphoric acid as well as concentration of EY on the sensitization hydrogen evolution were investigated. The possible mechanism was discussed. [ABSTRACT FROM AUTHOR]

Abstract: Stability issue of dye limits greatly applications of sensitization systems. In the present work, TiO2 was modified with a lacunary Keggin-type polyoxometalate SiW11O39 8− (SiW11). SiW11 is bound at TiO2 by a chemical interaction and its modification promotes TiO2 crystallization as well as growth of the particles. The as-prepared SiW11/TiO2 was used to construct a stable and efficient system for visible-light H2 generation using Eosin Y (EY) as a photosensitizer and Pt as a co-catalyst. SiW11 plays a very important role in enhancement of the sensitization activity and stability of SiW11/TiO2. SiW11 as an excellent electron relay greatly facilitates the electron transfer from the reduced dye species EY − to conduction band (CB) of TiO2 and suppresses the decomposition of EY −. Thus, a stable dye-sensitized hydrogen generation system is achieved. The factors which influenced the photocatalytic hydrogen evolution such as concentration of SiW11, concentration of EY, and Pt loading content were investigated. Under the optimal conditions, an average apparent quantum yield of 11.4% was obtained during 20 h irradiation (λ > 420 nm). The possible mechanism was discussed. [Copyright &y& Elsevier]

Searching for non-noble-metal cocatalyst for hydrogen evolution in photocatalytic water–splitting has attracted much attention. Herein, molybdenum phosphide (MoP) as an efficient and stable cocatalyst was prepared in a facile phosphorization process at relatively low temperatures under N 2 atmosphere, and the effect of preparation temperature (300–500 °C) was studied. Using Eosin Y (EY) and the prepared sample as catalyst (sensitizer) and cocatalyst, respectively, the photocatalytic activity for hydrogen evolution was investigated in aqueous trimethylamine (TMA) solution under visible light irradiation (λ ≥ 420 nm). MoP prepared at 400 °C (MoP-400) exhibits the highest sensitization activity and superior stability, and the maximal apparent quantum yield (AQY) for hydrogen evolution is up to 48.0% at 420 nm, much higher than the most reported data for MoP-based photocatalysts. The highest activity can be attributed to the highest P content in MoP-400 and the rapidest electron transfer between photoexcited EY and MoP-400. The possible mechanism was discussed. [Display omitted] • Molybdenum phosphide (MoP) as a cocatalyst for EY-sensitized photocatalytic HER. • The effect of preparation temperature of MoP was studied. • MoP-400 exhibits the highest sensitization activity and superior stability. • The possible mechanism for EY-sensitized photocatalytic HER was proposed. [ABSTRACT FROM AUTHOR]

Abstract: Zr-doped TiO2 nanotube arrays (Zr-TiO2-NT) and TiO2 nanotube arrays (TiO2-NT) were prepared via anodic oxidation of titanium foils in ethylene glycol solution and modified by heat treatment in the presence of urea pyrolysis products at 400°C. Zr doping changes the morphology of Zr-TiO2-NT and its conduction band edge shifts negatively compared with that of TiO2-NT. For the modification of Zr-TiO2-NT in the presence of urea pyrolysis products, Zr doping can not only enhance the polymerization degree of the surface-modified carbon nitride polymers but also promote the N doping. The modified TiO2-NT and Zr-TiO2-NT films exhibit significant photocurrent responses upon visible light irradiation. Zr doping improves markedly the visible-light photoelectrochemical H2 production of the modified Zr-TiO2-NT. [Copyright &y& Elsevier]

Abstract: Using ethanolamine (EA), diethanolamine (di-EA) and triethanolamine (tri-EA) as electron donors, the photocatalytic hydrogen evolution and decomposition of the electron donors (pollutants) over Pt/ZnIn2S4 have been investigated. The Pt was deposited on ZnIn2S4 by in situ photoreduction. The three ethanolamines improve notably photocatalytic hydrogen generation with their simultaneous degradation, and their activity order for hydrogen evolution is tri-EA≫di-EA>EA. The adsorption of these donors on ZnIn2S4 was monitored by in situ attenuated total reflection infrared spectroscopy (ATRIR). The order of their adsorption intensity is EA>di-EA≫tri-EA. The activity order depends on their molecular structure and adsorption performance. The effect of concentration of the pollutants on the hydrogen generation rate is consistent with a Langmuir–Hinshelwood kinetic model. The weak basic condition is favorable for the photocatalytic hydrogen generation. A possible reaction mechanism was discussed. [Copyright &y& Elsevier]

Abstract: It is important to construct a stable and efficient dye sensitization system for visible-light photocatalytic hydrogen evolution. Eosin Y (EY)-sensitized α-[AlSiW11(H2O)O39]5− (AlSiW11) (an Al3+ substituted Keggin polyoxometalate (POM)) for the hydrogen evolution under visible light irradiation (λ > 420 nm) has been carried out in the presence of triethanolamine as electron donor and Pt as co-catalyst. EY can coordinate with AlSiW11. The coordination association between AlSiW11 and EY is beneficial to the charge transfer from EY to AlSiW11 and to stability of EY. The system displays efficient and stable photocatalytic hydrogen evolution. The average apparent quantum efficiency and turnover number of EY during 20 h irradiation (λ > 420 nm) are 10.3% and 473, respectively. The highest quantum efficiency amounts to 28.0% under 520 nm monochromatic light irradiation. The present study highlights linking between dye and POM molecule as a way to develop new visible-light stable photocatalyst or system. [Copyright &y& Elsevier]

Abstract: Effects of α-d- and β-d-glucose as electron donors on photocatalytic hydrogen generation over Pt/TiO2 have been investigated. α-d-Glucose exhibits better photocatalytic activity for hydrogen evolution than β-d-glucose. The effects of initial pH of the anomer solutions on photocatalytic hydrogen generation have also been studied. Weak basic condition is favorable for the photocatalytic hydrogen generation. There is a large activity difference between α-d- and β-d-glucose under neutral condition, while the difference is very small under basic and acidic conditions. The possible mechanism was discussed. [Copyright &y& Elsevier]

Abstract: Photocatalytic hydrogen production was investigated over ZnS1−x−0.5y O x (OH) y –ZnO using sulfide ion (Na2S–Na2SO3) as an electron donor from NaCl saltwater. NaCl can affect markedly the activity for photocatalytic hydrogen production, depending on NaCl concentration. When NaCl concentration is lower, the activity is lower than that in pure water, whereas when NaCl concentration is higher, the activity is higher than that in pure water. NaCl decreases not only the surface charge of ZnS1−x−0.5y O x (OH) y –ZnO but also the surface hydration. When ZnS1−x−0.5y O x (OH) y –ZnO was impregnated with the electron donor (Na2S–Na2SO3), ZnO was transformed partly into ZnS. The impregnated ZnS1−x−0.5y O x (OH) y –ZnO exhibits higher activity than the non-impregnated one. The possible mechanisms were discussed. [Copyright &y& Elsevier]

Zn-In-S composites were synthesized by a NaCl-assisted hydrothermal method and characterized by an X-ray diffractometer (XRD), Scanning electron microscope (SEM), Energy dispersive spectrometer (EDS), BET, UV-Vis absorption spectrometer and inductively coupled plasma-atomic emission spectrometer (ICP). The products obtained by the hydrothermal method are a single ZnIn2S4or a composite of ZnIn2S4, ZnmIn2Sm+3, ZnS and In2S3, depending on the NaCl concentration. The samples are consisted of microspheres and sheet-like grains with a marigold-like superstructure. The grain size of the products increases and the specific surface area decreases with an increase of the NaCl concentration. Their photoactivities were evaluated by hydrogen evolution from an aqueous triethanolamine solution under visible light (λ ≥ 420 nm) irradiation. 0.50 wt% Pt was deposited on the samples for the photocatalytic hydrogen evolution by in situphotoreduction. The sample obtained in the presence of 0.20 mol L−1NaCl exhibits the highest activity for hydrogen evolution, ca.4 times as high as that of the sample prepared without NaCl. A possible mechanism was discussed. [ABSTRACT FROM AUTHOR]

Abstract: The effects of electrolyte NaCl, a major component of natural seawater, on photocatalytic hydrogen evolution in the presence of electron donors over Pt/TiO2 have been investigated. The adsorption performance and surface reaction of electrolyte NaCl and the electron donors on TiO2 have been characterized by electrophoretic analysis and in situ attenuated total reflectance infrared spectroscopy. Under acidic condition Cl− ions are adsorbed on TiO2, while under neutral and basic condition Na+ ions are adsorbed on TiO2. In the case of ethanol as an electron donor, the activity of photocatalytic hydrogen evolution over Pt/TiO2 increases when concentration of NaCl<0.10molL−1, while the activity decreases when the concentration>0.10molL−1. At different pH values, the activity decreases in the order: basic>neutral>acidic. In the cases of formic acid and oxalic acid as electron donors, the activities decrease with increase of NaCl concentration. The Na+ ions can affect adsorption performance of ethanol on TiO2. Possible reaction mechanisms were discussed. [Copyright &y& Elsevier]

Abstract: Surface property of Cd0.5Zn0.5S in basic aqueous solution was characterized by X-ray photoelectron spectroscope (XPS). The surface S species at Cd0.5Zn0.5S under basic condition is substituted by O species. The surface adsorption performance of glucose and NaCl was characterized by adsorption experiment and electrophoretic analysis. Glucose is adsorbed on Cd0.5Zn0.5S via two modes. Na+ can be also adsorbed on Cd0.5Zn0.5S. The effect of electrolyte NaCl on photocatalytic hydrogen evolution over Pt/Cd0.5Zn0.5S using glucose as an electron donor has been investigated under visible light irradiation. NaCl can promote markedly the photocatalytic hydrogen evolution, which is very important to practical application. The photocatalytic activity for hydrogen evolution from 3.0 mol L−1 NaCl saltwater increases by 77% compared to that from pure water. A possible mechanism was discussed. [Copyright &y& Elsevier]

Abstract: A nitrogen-doped TiO2 (N-TiO2) photocatalyst was prepared by calcination of the hydrolysis precipitate of Ti(SO4)2 with aqueous ammonia. The prepared N-TiO2 was treated with NH4F (F-N-TiO2) by an impregnation-calcination method. The photocatalyst (F-N-TiO2) was characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR), UV–vis diffusive reflectance spectroscopy (DRS), BET and X-ray photoelectron spectroscopy (XPS). With blue light-emitting diode (LED) as the light source, its photocatalytic activity for the degradation of formaldehyde was investigated. NH4F treatment enhances markedly photocatalytic activity of N-TiO2. The treatment increases the visible absorption of N-TiO2, decreases its specific surface area and influences the concentration of oxygen vacancies in N-TiO2. Photocatalytic activity of F-N-TiO2 depends on the visible absorption, the specific surface area, and the concentration of oxygen vacancies. The preparation conditions, such as the calcination temperature and the initial molar ratio of NH4F to N-TiO2, have a significant influence on the photocatalytic activity. The doping mechanism of NH4F was investigated. [ABSTRACT FROM AUTHOR]

Abstract: ZnS coated ZnIn2S4 (ZnS–ZnIn2S4) photocatalysts were prepared in methanol by a facile solvothermal process. The photocatalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), UV–Vis diffusive reflectance spectroscopy (DRS), BET, and electrochemistry measurements. ZnS–ZnIn2S4 photocatalysts have hexagonal crystal phase and complex morphology such as micro-spheres, micro-tubes and micro-ribbons. Using glucose as an electron donor, photocatalytic hydrogen generation over Pt/ZnS–ZnIn2S4 was investigated. The results show that photoactivity of hydrogen generation over Pt/ZnS–ZnIn2S4 was improved notably with simultaneous degradation of glucose. The factors which affect photocatalytic hydrogen generation, such as composition of ZnS-ZnIn2S4, initial concentration of glucose and concentration of NaOH, were investigated. The prepared ZnS–ZnIn2S4 photocatalysts exhibit better activity for hydrogen generation than pure ZnIn2S4, which may be attributed to enhancement of the adsorption of glucose by ZnS on the ZnIn2S4 surface. The effect of glucose concentration on the hydrogen generation rate is consistent with a Langmuir model. The basic condition is favorable for the photocatalytic hydrogen generation. A large number of ·OH radicals generated in ZnS–ZnIn2S4 system, have been tested by a TA-FL (terephthalic acid-fluorescence) method. A possible mechanism was discussed. [Copyright &y& Elsevier]

Abstract: An efficient visible-light active photocatalyst of multilayer-Eosin Y-sensitized TiO2 is prepared through linkage of Fe3+ between not only TiO2 and Eosin Y but also different Eosin Y molecules to form three-dimensional polymeric dye structure. The multilayer-dye-sensitized photocatalyst is found to have high light harvesting efficiency and photocatalytic activity for hydrogen evolution under visible light irradiation (λ >420nm). On the optimum conditions (1:1 initial molar ratio of Eosin Y to Fe(NO3)3, initial 10×10−3 M Eosin Y, and 1.0 wt% Pt deposited by in situ photoreduction), its maximal apparent quantum yield for hydrogen evolution is 19.1% from aqueous triethanolamine solution (TEOA aq). The present study highlights linking between dye molecules via metal ions as a general way to develop efficient visible-light photocatalyst. [Copyright &y& Elsevier]

Abstract: A composite visible light photocatalyst was prepared through co-precipitation of Zn(NO3)2 in the mixed solution of aqueous Na2S and NaOH, and calcination in N2 atmosphere. The photocatalyst was characterized by thermogravimetric and differential thermal analysis (TG–DTA), X-ray diffraction (XRD), UV–vis diffusive reflectance spectroscopy (DRS), BET and electrochemistry measurements. Its activity was evaluated by hydrogen production from an aqueous solution containing Na2S and Na2SO3 as hole scavengers under visible light (λ ≥420nm) irradiation. The photocatalyst is a mixture of basic zincoxysulfide (ZnS1−x−0.5y O x (OH) y ) solid solution and ZnO or only the solid solution. ZnS1−x−0.5y O x (OH) y , which was visible light active, was a solid solution of ZnS with dissolved oxygen and hydroxide groups. Hydroxide groups are very important in the formation and stabilization of the solid solution. The precipitation and calcination temperatures as well as the precursor composition of ZnS1−x−0.5y O x (OH) y have great influence on the photocatalytic activity. With 1:1 calculated molar ratio of ZnS to ZnO (or Zn(OH)2), ZnS1−x−0.5y O x (OH) y photocatalyst prepared via co-precipitation at 373K and calcination at 673K under N2 atmosphere exhibits the highest activity. Its apparent quantum yield without noble metal cocatalyst is ca. 3.0% under visible light irradiation. [Copyright &y& Elsevier]

Abstract: A visible-light boron and nitrogen co-doped titania (B–N–TiO2) photocatalyst was prepared by sol–gel method with titanium tetra-n-butyl oxide, urea and boric acid as precursors. The photocatalyst was characterized by Fourier Transform Infrared (FT-IR), UV–vis diffusive reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), BET and electrochemistry method. Photocatalytic activity for hydrogen production over platinized B–N–TiO2 under visible-light (λ ≥420nm) irradiation was investigated. In nitrogen doped titania (N–TiO2) Nph name="sbnd" />O bond is formed, which extends the absorption edge to the visible-light region. A part of doping boron enters into titania lattice and most of the boron exists at the surface of the catalyst. The crystallite size of B–N–TiO2 decreases compared to N–TiO2, while its photocurrent and the surface hydroxyl group increase. Furthermore, doping boron could act as shallow traps for photoinduced electrons to prolong the life of the electrons and holes. Therefore, the visible-light activity of B–N–iO2 increases greatly compared with that of N–TiO2. [Copyright &y& Elsevier]

Abstract: CdS semiconductor photocatalyst was synthesized by a solvent thermal process. Platinum (Pt) was loaded on the CdS by photodeposition. The samples were characterized by XRD, BET, TEM, DRS and XPS techniques. The activities of Pt/CdS photocatalysts under visible light were evaluated by hydrogen production using formic acid as electron donor. The photoetching of CdS was monitored by measuring dissolved . The activity of Pt/CdS with 1h photoetching treatment increases by 126% compared to the initial photocatalyst. However, excess photoetching decreases the photocatalytic activity. A distinct correlation between photoetching and increase of the activity is observed. Oxygen and platinum play an important role in the photoetching process. The photocatalytic activity is enhanced through decreasing agglomeration of the CdS particles to increase the specific surface area, modifying particle morphology, and removing selectively grain boundary defects which are recombination centers of photoinduced electron–hole pairs. [Copyright &y& Elsevier]

Abstract: A nitrogen-doped TiO2 (N-TiO2) photocatalyst was prepared by the calcination of the hydrolysis product of Ti(SO4)2 with aqueous ammonia. Pt was loaded on N-TiO2 by photodeposition method. A dye-sensitization photocatalyst was prepared by impregnation method with Eosin Y and the platinized N-TiO2. The prepared samples were characterized by XRD, UV–vis diffuse reflectance spectra (DRS), BET and FT-IR. The visible light activity of the sensitization photocatalysts was evaluated by photocatalytic hydrogen evolution (λ >420nm) in the presence of electron donor triethanolamine (TEOA). The N-TiO2 has smaller crystalline size and larger specific surface area to enhance the adsorption amount of Eosin Y than TiO2 prepared by NaOH. Surface oxygen defects produced by nitrogen doping would improve the adsorption of Eosin Y and excited electron to transfer to the conduction band of N-TiO2. Therefore the visible light activity of the sensitized nitrogen-doped platinized TiO2 is much higher than that of the sensitized platinized TiO2. The sensitized nitrogen-doped platinized TiO2 calcined at 300°C has the highest visible light activity among the catalysts calcined at various temperatures, whose activity is increased by a factor of 3 compared to that of the sensitized platinized TiO2 calcined at the same temperature. [Copyright &y& Elsevier]

Abstract: In the presence of chloroacetic acids, the photocatalytic hydrogen evolution and decomposition of the pollutants over Pt/TiO2 have been investigated. The Pt/TiO2 was prepared by photodeposition. Monochloroacetic acid and dichloroacetic acid enhance photocatalytic hydrogen generation, whereas trichloroacetic acid does not. The photocatalytic oxidation of monochloroacetic acid and dichloroacetic acid mainly produces CO2, HCl and formaldehyde, whereas the photocatalytic oxidation of trichloroacetic acid mainly produces CO2 and HCl. The effect of the concentration of monochloroacetic acid and dichloroacetic acid on the hydrogen generation rate is consistent with a Langmuir–Hinshelwood kinetic model. A possible reaction mechanism was discussed. [Copyright &y& Elsevier]

Abstract: Colloidal platinum nanoparticles, the co-catalyst for hydrogen evolution, were prepared using 12-tungstosilicate as photocatalyst by two methods in which photolysis and reduction reaction took place at the same time and at different time, respectively. For the former, H2PtCl6 was reduced directly to colloidal platinum under irradiation and 12-tungstosilicate would transfer into a new structure compound during the process. For the latter, 12-tungstosilicate was first photoreduced to heteropoly blue anion, and then the blue anion could reduce H2PtCl6 to colloidal platinum under no irradiation. The Pt particle size and reactivity of 12-tungstosilicate were characterized by UV–vis and cyclic voltammetry. Preparation methods affect markedly the Pt particle size and reactivity of 12-tungstosilicate so that the photocatalytic activity and stability for hydrogen evolution are different. The possible mechanism was discussed. [Copyright &y& Elsevier]

Rare-earth nickelates (such as perovskite RNiO3, trilayer R4Ni3O10, and infinite layer RNiO2) have attracted tremendous interest very recently. However, unlike the widely studied RNiO3 and RNiO2 films, the synthesis of trilayer nickelate R4Ni3O10 films is rarely reported. Here, single-crystalline (Nd0.8Sr0.2)4Ni3O10 epitaxial films were coherently grown on SrTiO3 substrates by high-pressure magnetron sputtering. The crystal and electronic structures of (Nd0.8Sr0.2)4Ni3O10 films with oxygen ligand holes were characterized by high-resolution x-ray diffraction, x-ray photoemission spectroscopy, and resonant soft x-ray absorption spectroscopy. The electrical transport measurements reveal a metal–insulator transition behavior near 82 K and negative magnetoresistance in (Nd0.8Sr0.2)4Ni3O10 films. Our work provides a novel route to synthesize high-quality trilayer nickelate R4Ni3O10 films with RNiO3 targets by high-pressure magnetron sputtering. [ABSTRACT FROM AUTHOR]

Realizing ultrathin water and generating an abundant water/air interface in the interconnected pores of photothermal materials is an effective way to boost the solar‐driven water evaporation rate, but still a great challenge. Herein, confinement capillarity (CC) of photothermal thin coating on porous sponge for significantly enhancing the solar‐driven water evaporation is proposed. The thin coating is composed of abundant agminated black/hydrophilic nanoparticles (BHNPs), and the channels among the BHNPs can generate strong capillarity for water transportation. Water can be spontaneously limited and transported among the agminated nanoparticles, rather than fill in the interconnected pores of the sponge. Thus, ultrathin water layer can be realized on the outer/inner surface of the sponge skeleton, without precisely controlling water supply. The thin water layer can not only expose as much evaporation area as possible by increasing the vapor escape channel, but also prevent solar energy to heat excess water. Thanks to the CC, the rate of solar steam generation can be greatly improved. Moreover, the photothermal material with CC can maintain its high evaporation rate during the whole day, and can remove the salt during night time, highlighting its recyclability and anti‐salt‐accumulation property. Moreover, the CC can be readily scaled up for practical applications. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop efficient and cost-effective composite catalysts to replace noble metal Pt for hydrogen evolution reaction (HER). For an excellent HER catalyst, both the adsorption and desorption of intermediate H atoms on it should be easy. However, except metal platinum, most individual species cannot satisfy this requirement. Fe-B is an active HER catalyst with strong ability to adsorb H atoms. In our previous work, we found that when Fe-B alloy was decorated with metal Fe particles (Fe-B@Fe), the resultant composite displayed a significant synergic effect for HER compared to single Fe-B and Fe. The role of the decorated Fe on Fe-B is to improve H 2 desorption. Because the desorption of H 2 molecule from Ni is easier than from Fe, we expect Fe-B@Ni to be a more efficient HER catalyst than Fe-B@Fe. Herein, we transform Fe-B@Fe into Fe-B@Ni by a facile displacement reaction. As a proof of concept, the as-prepared Fe-B@Ni catalyst exhibits much higher electrocatalytic and photocatalytic activity for hydrogen production than the pristine Fe-B@Fe. At the current density of −100 mA cm−2, the overpotential of Fe-B@Ni in 1.0 mol L−1 KOH is close to that of 20 wt% Pt/C. The highest apparent quantum yield (AQY) for dye-sensitized photocatalytic hydrogen evolution reaches 51% at 420 nm. The possible mechanisms have been proposed. These findings provide new insights for designing and fabricating new HER composite catalysts for electrocatalytic and photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

• Nickel oxide/nickel carbide/graphene composite was synthesized via one-step thermal treatment. • The graphene increases the conductivity and the distribution of nickel species. • The nickel carbide acts as the active sites for hydrogen evolution reaction (HER). • The NiO improves H 2 O dissociation and HER in the basic solution. • The composite exhibits synergistic electrocatalytic and photocatalytic HER activity. To resolve the energy crisis and environment pollution, it is urgent to explore highly efficient and inexpensive catalysts for hydrogen evolution reaction (HER). In this work, we fabricate nickel oxide/nickel carbide/graphene (labeled as NNG) composite via one-step thermal treatment of NiCl 2 /graphene oxide (GO) as the precursor at relatively low temperature. GO plays a role of the carbon source to form nickel carbide and increases the distribution of the nickel species. The formed nickel carbide acts as the active sites for hydrogen atoms adsorption (H ads). The NiO contacted with the nickel carbide promotes the Volmer reaction: H 2 O+e → H ads +O H -. The two different adsorption sites (nickel carbide for H ads , NiO for OH−) jointly lead to the HER synergistic effect in basic solution. The obtained composites exhibit much higher dye-sensitized photocatalytic and electrocatalytic HER activities than nickel carbide, NiO and RGO alone. The highest apparent quantum yield (AQY) of dye-sensitized hydrogen evolution for NNG12 at 420 nm reaches 39.4%. And the electrocatalytic HER overpotential is -0.28 V at the current density of 10 mA cm-2 in 1.0 mol L-1 KOH. To the best of our knowledge, it is the first time to report nickel oxide/nickel carbide as an efficient HER catalyst in alkaline media. This work paves a way for facile and green fabrication of the efficient HER cocatalysts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel J-J type Zn m In 2 S m+3 @In 2 S 3 heterojunction was designed based on conductive anisotropy. • The J-J type heterojunction was fabricated with the assistance of oxalic acid. • The heterojunction improves the carrier separation efficiency and extends light response range. • The heterojunction exhibits significantly enhanced photocatalytic H 2 evolution activity. Abstract It remains a great challenge to design and prepare highly efficient semiconductor-based photocatalysts for water splitting. To achieve this goal, the design of oriented heterojunctions for efficient carrier transport and separation is a new strategy based on their conductive anisotropy. Herein, a novel oriented J-J type Zn m In 2 S m+3 @In 2 S 3 heterojunction photocatalyst with hierarchical structures is fabricated with the assistance of oxalic acid. The hierarchical structures consist of 'flower-like' hollow Zn m In 2 S m+3 microspheres with epitaxially grown quantum confined In 2 S 3 along the petal rims (J-J type heterojunction). This heterojunction improves the transport and separation of the photoexcited carriers, and extends the visible-light response range. Thus, the heterojunction photocatalyst exhibits significantly enhanced photocatalytic activity with a hydrogen evolution rate of 330 μmol h−1, which is about 4 times higher than that of single ZnIn 2 S 4. The findings provide new insights to construct efficient oriented heterojunctions for anisotropic semiconductors. [ABSTRACT FROM AUTHOR]

Highlights • The secondary reactions of the TA- APTES coating has been investigated. • (TA-APTES)-based materials exhibit better performance than PDA-based materials. • The reasons for the significantly improved performance have been revealed. Abstract Secondary reactions of surface coating are of great importance and have drawn great attentions, since it can make the coating as a versatile platform for different uses via tailoring surface properties. A good example is the polydopamine (PDA) coating which has been widely used for preparation of various functional materials owing to its secondary reactions. In our recent study, we have developed hierarchical tannic acid (TA)-aminopropyltriethoxysilane (APTES) coating with distinct layer-nanospheres structure. Herein, the secondary reactions of the TA-APTES coating has been investigated in detail. And for the first time, various (TA-APTES)-based functional materials including superhydrophobic, adsorbent, and catalytic materials have been prepared for oil/water separation, dye adsorption, and 4-nitrophenol reduction, respectively. Significantly, under the same conditions, the performance of the (TA-APTES)-based functional materials is much better than that of the PDA-based materials: (a) The adsorptive capacity of the (TA-APTES)-based adsorbent toward rose bengal, methyl bule, orange G, and amaranthus red is 80.1%, 96.2%, 86.1%, and 98.6% higher than that of the PDA-based adsorbent, respectively; (b) The (TA-APTES)-based catalytic material can reduce about 98% of 4-NP in 10 min, while the PDA-based material can only reduce 60% of 4-NP under the same conditions; (c) After reacting with octadecyltrimethoxysilane, the TA-APTES coating can be directly transformed into superhydrophobic coating for oil/water separation, while the PDA coating is only hydrophobic and cannot separate oil/water mixture. The reasons for the significantly improved performance of the (TA-APTES)-based materials have been revealed. Our findings demonstrate that the TA-APTES coating can act as an outstanding platform for preparation of various functional materials with preferable performance, and the TA-APTES coating will be a promising substitute for PDA coatings. [ABSTRACT FROM AUTHOR]

Dual functional membranes with super-wetting and adsorption capacity have drawn great attentions owing to their good application prospect in the treatment of mixed wastewater containing oil and dyes. Despite recent development in such functional membranes, there are still some obstacles need to be resolved. The one is how to further improve the dye adsorption capacity to realize the high-efficiency removal of dye under high permeation flux. The other is to improve the rejection towards nano-sized oil droplets in water. Herein, with porous polypropylene (PP) membrane as substrate, we show that constructing multiple hierarchical structures (MHS) on membrane surface is an effective way to solve the above mentioned problems. The MHS prepared by low-cost tannic acid, 3-Aminopropyltriethoxysilane (APTES), and polyethyleneimine (PEI) are composed of rough layer, nanospheres, and nano nodes with abundant amine groups. On the one hand, the MHS can endow the membrane with high adsorptive capacity (480 mg g −1 toward methyl blue). On the other hand, the MHS can also decrease the pore size of the membrane, making it suitable for separation of nano-sized oil droplets. Moreover, the MHS can also render the membrane superhydrophilicity and excellent anti-oil-adhesion properties. Thanks to these advantages derived from MHS, the obtained dual functional membrane can realize high-efficiency and simultaneous removal of high concentrated dye (10–50 ppm, removal efficiency>95%) and nano-sized oil droplets (about 50–300 nm, oil rejection>99%) from mixed wastewater under high flux (1680 L m −2 h −1 ). Considering the significantly enhanced performance, as well as the facile and cost-effective process, the as-prepared functional membrane with MHS has good application prospects. Besides, a new insight on the influence of hydrodynamic conditions on membrane fouling during emulsion separation is also proposed, which may guide better design of anti-fouling membranes. [ABSTRACT FROM AUTHOR]