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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]

[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]

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]

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]

Transition metal electrocatalysts with crystalline-amorphous heterostructures have garnered particular attention owing to the pronounced synergistic effect between a crystalline phase with high electrical conductivity and an amorphous phase with abundant catalytic active sites. Herein, we construct crystalline-amorphous Ni-Ni(OH) 2 hybrids via a facile electrodeposition approach for efficient alkaline hydrogen evolution reaction (HER). The Ni-Ni(OH) 2 heterostructures are directly electrodeposited on the surface of Cu nanowires (NWs) in-situ grown on Cu foam with a well-maintained nanowire morphology. The Cu NWs on Cu foam substrate provide a three-dimensional structure, and enable efficient electron transportation to the Ni-Ni(OH) 2 sites. Moreover, in the crystalline-amorphous Ni-Ni(OH) 2 heterostructures, amorphous Ni(OH) 2 nanosheets accelerate the water dissociation, while crystalline Ni active sites promote the formation and combination of adsorbed hydrogen atoms. Such a promising synergistic effect leads to the enhanced HER performance with low overpotentials of 73 and 336 mV at the current densities of 10 and 100 mA cm−2, respectively, and a small Tafel slope of 33 mV dec−1. In addition, the integrated structure enables the Ni-Ni(OH) 2 electrode with a durable stability of 35 mA cm−2 for 100 h. This work offers an effective approach to construct crystalline-amorphous materials for efficient alkaline HER. [Display omitted] • Crystalline-amorphous Ni-Ni(OH) 2 hybrids are electrodeposited on Cu NWs in-situ grown on Cu foam. • The three-dimensional Cu NWs on Cu foam enables efficient electron transportation. • Amorphous Ni(OH) 2 nanosheets accelerate the water dissociation. • Crystalline Ni sites promote the formation of adsorbed hydrogen atoms. • The synergistic effect leads to the enhanced HER performance of Ni-Ni(OH) 2 heterostructures. [ABSTRACT FROM AUTHOR]

It remains a challenge to develop efficient and inexpensive catalysts for hydrogen evolution reaction (HER). Herein, it is the first time to report a core-shell structured amorphous Fe-B alloy coupled with metal Fe nanoclusters as an efficient HER catalyst. The composite was fabricated via the transformation of the FeOOH coating on amorphous Fe-B alloy into metal Fe through a simple photoreduction approach. The Fe nanoclusters loaded on amorphous Fe-B alloy improve the catalytic HER. Thus, the as-prepared composite exhibits much better electrocatalytic and photocatalytic HER activities than single Fe and Fe-B alloy, that is, there is a synergic effect between Fe metal and amorphous Fe-B alloy. The highest apparent quantum yield (AQY) for photocatalytic HER reaches 34% at 470 nm with Eosin Y as a photosensitizer. The composite cocatalyst can be recovered by a magnetic field after the dye-sensitized photocatalytic HER. More interestingly, the electrocatalytic HER activity of Fe-B@Fe-10 in alkaline solution surpasses that of foam Ni used in industrial water electrolysis, and the core-shell composite shows excellent HER performance at high current density. The findings provide new insights to develop efficient and stable noble-metal-free HER catalysts. [ABSTRACT FROM AUTHOR]

The construction of a composite photocatalyst with two suitable semiconductors is an effective strategy to improve the transport and separation of the photoexcited carrier pairs. Herein, it is the first time to report the new concept of anisotropic heterojunctions (H and J type) in layered ZnIn 2 S 4 nanosheets as an example. Due to the anisotropic conductivity, the resistance of the electron transfer along ZnIn 2 S 4 layers to a second semiconductor (J type heterojunction), is much less than that across the layers (H type heterojunction). As a result, the J type heterojunction can achieve higher photocatalytic activity than H type one. Furthermore, ZnIn 2 S 4 /In(OH) 3 heterojunction with the J type structure was successfully fabricated by a simple approach, namely, In(OH) 3 was selectively assembled at the rims of ZnIn 2 S 4 nanosheets via hydrothermal transformation of the precursor precipitate with its mother solution obtained by adding Na 2 S into the solution of stoichiometric In 3+ and excessive Zn 2+ . The intimate-contact J type heterojunction with in-situ photodeposited Pt shows efficient photocatalytic H 2 evolution under visible irradiation, leading to a high apparent quantum yield of 38.3% at 420 nm with a low optimal Pt loading of 0.25 wt%. This work provides a new insight for the development of efficient heterojunction photocatalysts with layered semiconductors. [ABSTRACT FROM AUTHOR]

The reasonable introduction of Cu into Ni significantly enhances the metal-support interaction of NiCu/graphene cocatalysts, which gives rise to smaller size of NiCu nanocatalysts and facilitates the interface electron transfer for enhancing dye-sensitized photocatalytic H 2 evolution performance. [Display omitted] • The introduction of Cu enhances the metal-support interaction (MSI) between Ni and graphene. • The enhanced MSI facilitates the electron transfer from dye EY to NiCu/graphene cocatalysts. • The introduction of Cu modulates the hydrogen adsorption on NiCu alloy surface. • The electrocatalytic and dye-sensitized photocatalytic HER performances of NiCu/graphene cocatalysts are much improved. The modulation of metal-support interaction (MSI) is of particular interest in improving the catalytic performance of metal nanocatalysts. Herein, we adopt an alloying strategy to tune the MSI in graphene-supported Ni catalyst by introducing Cu. The NiCu/graphene cocatalysts (denoted as N x C y G) are facilely synthesized by directly calcinating the mixture of metal chlorides and graphene oxide for dye-sensitized photocatalytic hydrogen evolution reaction (HER). The results reveal the introduction of Cu significantly affects the MSI in N x C y G cocatalysts, and a reasonable Ni/Cu ratio (4:1) significantly enhances the MSI in N 4 C 1 G cocatalyst. Such an enhanced MSI facilitates the electron injection from excited dye to RGO and further transfer to the NiCu alloy, and leads to smaller size of NiCu alloy nanoparticles (NPs) with sufficient active sites. Moreover, the synergetic effect between Ni and Cu is conducive to optimize the hydrogen adsorption on NiCu surface. As a result, the N 4 C 1 G cocatalyst shows much improved electrocatalytic and photocatalytic HER performance compared with monometallic Ni/graphene and Cu/graphene. The apparent quantum yield (AQY) at 420 nm reaches up to 67.7 % in the dye-sensitization system. We believe that this work develops a facile and effective strategy to tune the MSI of metal/graphene catalysts for enhanced HER performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Porous hydrogel sponge has been realized via in-situ growth of hydrogel on sponge. • Hydrogel layer can be readily controlled to reserve the porosity of the sponge. • The "porous hydrogel sponge" can be arbitrarily compacted, folded, and twisted. • Water evaporation rate is up to 2.8 kg m-2h−1 under one sun with 332 g h−1 $−1. • Long-term cycling stability (>6 months), as large as 7500 cm2. Hydrogel evaporator is becoming an excellent platform for solar-driven water purification. However, the cost effectiveness and scalability of hydrogel-based evaporate materials is still a great challenge due to the high energy-consuming and time-consuming freeze drying process, as well as limited black hydrogel materials. Herein, inspired by porifera, "porous hydrogel sponge" has been proposed and realized via in-situ growth of novel adhesive/black hydrogel on polyurethane (PU) sponge without freeze drying process for durable and highly efficient solar-driven water evaporation. The in-situ generated hydrogel can firmly adhere on the sponge skeleton just like a skin, and the thickness of the hydrogel layer can be readily controlled to reserve the high porosity of the sponge, while the sponge skeleton can endow the evaporator with desirable mechanical stability (can be arbitrarily compacted, folded, and twisted). The water evaporation rate of the resultant hydrogel evaporator can reach up to 2.8 kg m-2h−1 under one sun with excellent cost-effectiveness at 332 g h−1 $−1. Moreover, the resultant hydrogel evaporator possesses outstanding long-term cycling stability (at least 6 months), and can be as large as 7500 cm2 (can be readily enlarged further). This study represents a new avenue for fabrication and design of high performance hydrogel evaporator toward practical application, and will contribute to the global effort in addressing world water and energy issues. [ABSTRACT FROM AUTHOR]

[Display omitted] • The triazine and heptazine units is directional modulated by a green approach. • Small content of SPP in-situ booss the formation of heptazine based CN. • Excess content of SPP tends to form triazine based CN. • The triazine and heptazine based SPP-MS-CN shows superior photocatalytic activity. Hollow SPP-MS-CN nanotubes have been developed through a green one-step approach by sodium polyphosphate (SPP) in-situ mediated molten salt (MS) thermal condensation of melamine for the first time. In which, the structure of SPP-MS-CN with triazine and heptazine units can been directionally modulated by the SPP content. The molten salts at high-temperature function as green solvents to facilitate mass transfer, which tends to form triazine based CN. Addition of SPP mediates the fluidity of molten salt system, which in-situ modulates the thermal condensation process, boosting the formation of the extended π-conjugated system of heptazine based CN. The 0.5 wt% SPP-MS-CN exhibit photocatalytic H 2 evolution rate up to 1785 µmol h−1 g−1, which is 2.16 times higher than that of molten salt synthesis of carbon nitride (MS-CN), even 14.5 times enhancement of photocatalytic H 2 evolution rate over pure CN obtained by directly thermal condensation of melamine. It reveals that the hollow structures endow SPP-MS-CN with increased specific surface area, and the formed heptazine structure of SPP-MS-CN benefit for charge carrier separation and transfer and H 2 reduction ability, which favors for the remarkable photocatalytic activity. Our work opens a new window for in-situ modulation of the structure of CN photocatalysts. [ABSTRACT FROM AUTHOR]

Tannic acid (TA)-aminopropyltriethoxysilane (APTES) coating has excellent hydrophilicity, and can be applied to a variety of materials. But it has poor stability in the air. To improve its stability, we have developed TA-APTES-Fe(III) coating in our previous work, but there are still some problems remained such as tedious steps, and undesirable anti-crude oil-adhesion performance, etc. Besides, both TA-APTES and TA-APTES-Fe(III) coating cannot realize the hydrophilic modification of the inner surfaces of porous polypropylene (PP) membrane. To solve the above mentioned problems, we developed superhydrophilic and stable TA-APTES- tetraethylorthosilicate (TEOS) coating via one-step process in this study. The new coating can realize the superhydrophilic modification of the inner surfaces of porous PP membrane, and endows the PP membrane with good water permeability, which cannot be realized by our previously reported TA-APTES and TA-APTES-Fe(III) coating. Besides, the stability of the coating is greatly improved by introducing stable alcoholic hydroxyl groups derived from TEOS, and the resultant modified membrane can keep superhydrophilic (CA about 0°) and underwater superhydrophobic (underwater oil CA above 150°) even after being stored in air for more than 6 months, ultrasonic treatment for 10 min, or being rinsed by water for 24 h (3000r/min), exhibiting outstanding stability. More importantly, the crude oil adhesion force of the new coating is as low as 4 μN even under the preload force of 300 μN, showing excellent anti-crude oil-adhesion property. The PP membrane modified by the new coating possesses ultrahigh water flux (10384 L m-2 h-1 bar-1) and can realize highly efficient separation of oil-in-water emulsion (above 99%). This work is expected to accelerate the practical application of TA-APTES coating. Image 1 • Only one step required to make the membrane superhydrophilic and long-term stable. • The TA-APTES-TEOS coating can make water easily penetrate through the membrane. • The roles of the TEOS have been revealed. • The TA-APTES-TEOS coating possesses outstanding anti-crude oil-adhesion property. [ABSTRACT FROM AUTHOR]

A new concept of volume photocatalysis of of solid catalysts is created, and an efficient reaction system constructed using low polymeric carbon nitride as a photocatalyst and biomass-derived formic acid as a reactant. The apparent quantum yield for photocatalytic hydrogen evolution reaches 51.9% at 400 nm in formic acid reaction system. • It is the first time to propose the concept of volume photocatalysis of solid catalysts. • Low polymeric carbon nitride (PCN) can act as a volume photocatalyst. • An efficient PCN photocatalytic H 2 evolution is achieved in formic acid reaction system. • Apparent quantum yield for photocatalytic H 2 generation at 400 nm reaches 51.9%. • This work provides a new strategy to enhance photocatalytic reaction efficiency. Conversion of solar energy into H 2 via photocatalytic reforming of biomass or its derivatives is an attractive technology. However, the photocatalytic reaction efficiency is usually low due to the high recombination of photogenerated electrons and holes. Herein, we demonstrate a new concept and strategy of volume photocatalysis of solid catalysts and construct an efficient reaction system using low polymeric carbon nitride (PCN) as a volume photocatalyst and biomass-derived formic acid as a reactant. In this system, PCN allows the reactant to enter its bulk and in-situ scavenge photogenerated holes, which greatly inhibits the recombination of the electrons and holes. As a result, the left electrons can effectively migrate from the bulk to the surface of PCN to reduce protons/water molecules into hydrogen. The apparent quantum yield (AQY) for photocatalytic hydrogen evolution reaches 51.9% at 400 nm in formic acid reaction system. These findings provide new insights for understanding heterogeneous photocatalysis. [ABSTRACT FROM AUTHOR]

• Ni-B coupled with borate-intercalated Ni(OH) 2 as a novel HER catalyst in alkaline system. • Intercalated borate enhances electro- and photo-catalytic HER activity and stability of the composite. • Interlayer borate improves proton transport from Ni(OH) 2 to Ni-B and stabilizes Ni(OH) 2. • This work provides new insights for design new composite HER catalysts at alkalinity. To convert solar energy into storable chemical fuel hydrogen via water splitting, it is highly required to develop efficient, low-cost and stable HER (hydrogen evolution reaction) catalysts and systems. For practical application, the HER catalysts can work in low alkaline or neutral reaction systems. However, in these reaction systems, water dissociation into proton is a rate-determining step, which can be overcome by loading metal oxide or hydroxides onto the HER catalysts. Ni(OH) 2 is a well-reported cocatalyst to assist water dissociation. Herein, Ni-B@Ni(OH) 2 [Ni-B with loaded Ni(OH) 2 as a HER catalyst at weak alkalinity has been investigated. Very interestingly, we find that when borate is added into the above reaction systems, the resultant catalyst Ni-B@Ni(OH) 2 -BI shows much better HER activity and stability than Ni-B@Ni(OH) 2. The reason is that borate ions can intercalate into Ni(OH) 2 interlayers, which increases proton transport ability and stability of Ni(OH) 2 loaded on Ni-B. These findings provide new insights for design new composite catalysts of HER in low alkaline reaction systems. [ABSTRACT FROM AUTHOR]

• This review concentrates on the nonmetal modulation of composition and morphology of g-C 3 N 4 -based photocatalysts. • The composition modulation is mainly on nonmetal elemental doping, dye-sensitization, and heterojunction construction. • The morphology modulation is mainly through nonmetal hard or soft templates, self-templates or template-free. • The applications of g-C 3 N 4 -based photocatalysts for water splitting, CO 2 reduction, and pollutants degradation are discussed. In recent years, metal-free graphitic carbon nitride (g-C 3 N 4) as a fascinating photocatalyst has become a research hot topic in energy conversion and environmental treatment. To date, great attentions are paid to nanostructures design, electronic structure modulation, and heterostructure construction of g-C 3 N 4. In terms of maintaining the metal-free nature of g-C 3 N 4 , nonmetal modulation of g-C 3 N 4 -based photocatalysts is charming and attractive because of the low-cost, earth-abundant, robust, and tunable properties. This review will focus on the nonmetal modulation of composition and morphology of g-C 3 N 4 -based photocatalysts, mainly on nonmetal elemental doping, copolymerization, dye-sensitization, and nonmetal heterojunction construction for the photocatalytic applications on water splitting, CO 2 reduction, and pollutants degradation, which shall endow the perceptions in regard to the development of metal-free g-C 3 N 4 -based photocatalysts in future, and pave a new research doorway to exploit low-cost metal-free photocatalysts as well as nonmetal elemental photocatalysts in the field of energy conversion, and environmental treatment. [ABSTRACT FROM AUTHOR]

• The C-TA/g-C 3 N 4 was obtained by supramolecular self-assembly and thermal condensation. • The TA with groups OH can link with melamine promoting the condensation of g-C 3 N 4. • The C-TA/g-C 3 N 4 with decreased interlayer distance effectively promote charge transfer. • The condensed C-TA/g-C 3 N 4 exhibit superior photocatalytic H2 evolution performance. Design of highly condensed g-C 3 N 4 is a prospective way to optimize the photoreactivity of g-C 3 N 4 as it possesses condensed structure with decreased interlayer spacing, which benefits both charge transfer and light harvesting. Herein, we report that novel condensed carbonized-tannic acid (C-TA)/g-C 3 N 4 composites have been acquired via a supramolecular self-assembly of TA and melamine into TA/melamine precursors followed by thermal condensation. The acquired condensed C-TA/g-C 3 N 4 composites present superior visible-light photocatalytic activity for H 2 evolution. The 1 wt% C-TA/g-C 3 N 4 composite shows 4.2 times enhancement of photocatalytic activity for H 2 evolution compared to pristine g-C 3 N 4. The TA with distinct adhesion properties and functional groups of OH, which is firmly linked with melamine, can confine the melamine inside to promote the condensation to gain more condensed g-C 3 N 4. The condensed C-TA/g-C 3 N 4 composites with decreased interlayer distance effectively promote charge transfer and photocatalytic H 2 evolution. [ABSTRACT FROM AUTHOR]

Tannic acid(TA)-aminopropyltriethoxysilane(APTES) coating possesses hierarchical structure and superhydrophilicity, and can be facilely coated on various porous membranes for oil-water separation. However, the TA-APTES coating will lose its superhydrophilicity and underwater superoleophobicity after being exposed to the air for more than one month. Besides, TA-APTES coating on membrane surface decomposes when the coating is immersed in acidic solution (pH ≤ 3) or alkaline solution (pH ≥ 12). In this study, the reasons for the instability of TA-APTES coating have been studied, and an effective strategy for significantly improving the stability of the coating has been developed via simple treatment with ferric ions. The coordination effect between ferric ions and the TA-APTES coating can not only restrain the oxidation of the phenolic hydroxyl groups, but also decrease the electrostatic repulsion and enhance the interactions between the chain segments. The resultant (TA-APTES)-Fe(III) coating possesses long-term superhydrophilicity and excellent acid-base resistance property, while the distinct and hierarchical structure of the TA-APTES coating can be reserved. Thanks to the outstanding stability of (TA-APTES)-Fe(III) coating, the PVDF-(TA-APTES)-Fe(III) membrane can maintain its outstanding anti-oil-fouling property and good oil/water separation performance even it is being exposed in air for one month or being immersed in strong acidic or alkaline solutions for 48 h, which is much better than the pristine PVDF-(TA-APTES) membrane. This study will accelerate the practical application of TA-APTES coating. Image 1 • The reasons for the instability of TA-APTES coating have been investigated. • The stability of TA-APTES coating has been significantly improved by incorporation of ferric ions. • The roles of the ferric ions have been revealed. • The modified TA-APTES coating possesses long-term superhydrophilicity and desirable acid-base resistance property. [ABSTRACT FROM AUTHOR]

Exploiting new, low-cost and efficient electrocatalysts for hydrogen evolution reaction (HER) is important to resolve the energy crisis and environment pollution. In this work, graphene decorated with Ni nanoparticles (NPs) were synthesized via one-pot reduction using graphene oxide (GO, the obtained composite was denoted as GN) as a precursor. The as-prepared composite GN exhibits much better electrocatalytic and dye-sensitized HER activities than single Ni and reduced graphene oxide (RGO), namely, a great synergetic effect of RGO and Ni for HER. The coupling of metal Ni with the defect carbons of RGO plays a key role in the synergetic effect. The structure of GN composites is another key factor to the synergetic effect. The highest apparent quantum yield (AQY) for dye-sensitized photocatalytic hydrogen evolution at 470 nm reaches 30.3% under the optimal conditions. [ABSTRACT FROM AUTHOR]