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Highlights: The 1T-WS2@TiO2@Ti3C2 photocatalyst is highly active for water splitting to produce hydrogen at 3409.8 μmol g−1 h−1. The Ti3C2 MXene and octahedral (1T) phase WS2 act pathways transferring photogenerated electrons. The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst's surface. In this paper, we report that double metallic co-catalysts Ti3C2 MXene and metallic octahedral (1T) phase tungsten disulfide (WS2) act pathways transferring photoexcited electrons in assisting the photocatalytic H2 evolution. TiO2 nanosheets were in situ grown on highly conductive Ti3C2 MXenes and 1T-WS2 nanoparticles were then uniformly distributed on TiO2@Ti3C2 composite. Thus, a distinctive 1T-WS2@TiO2@Ti3C2 composite with double metallic co-catalysts was achieved, and the content of 1T phase reaches 73%. The photocatalytic H2 evolution performance of 1T-WS2@TiO2@Ti3C2 composite with an optimized 15 wt% WS2 ratio is nearly 50 times higher than that of TiO2 nanosheets because of conductive Ti3C2 MXene and 1T-WS2 resulting in the increase of electron transfer efficiency. Besides, the 1T-WS2 on the surface of TiO2@Ti3C2 composite enhances the Brunauer–Emmett–Teller surface area and boosts the density of active site. [ABSTRACT FROM AUTHOR]

Herein, ultradispersed In2S3 nanoparticle (NP)/TiO2 nanobelt (NB) heterostructures with an intimate interfacial coupling effect are synthesized from the consideration of combining the visible/near-infrared photoabsorption property of In2S3 with the excellent UV photocatalytic property of TiO2. In this process, the 1D TiO2 NBs not only perform as the support to form the heterostructure, but are also employed as a dispersant to confine the aggregation of In2S3 NPs. As expected, the obtained In2S3 NP/TiO2 NB heterostructure gives rise to a prominently strong optical absorption in the full solar region of 300-1800 nm, and thus displays a desired photocatalytic degradation of tetracycline in full utilization of all solar energy, compared with that of pristine In2S3 and TiO2. Besides, the In2S3 NP/TiO2 NB heterostructure photocatalysts have no selectivity and can effectively degrade other different kinds of organic pollutants, including cationic dyes (methyl blue and rhodamine B) and colorless chemical pollutants (phenol and salicylic acid). The exceptional photocatalytic enhancement is due to the synergistic interactions of heterojunction with the strong interfacial coupling effect, the In2S3 extended light absorption, efficient photogenerated e−/h+ pair separation, and fully exposed reactive sites induced by uniform packing of the ultrasmall In2S3. [ABSTRACT FROM AUTHOR]

Recently, near-infrared light (NIR) photocatalysts, such as up-converting materials, Bi2WO6, Cu2(OH)PO4, and carbon quantum dots, have been found and are attracting attention for environmental cleaning and energy conversion, because NIR light constitutes nearly half of the energy output. However, the photocatalytic efficiency is low for these new types of NIR photocatalysts, which has limited their widespread application owing to their insufficient NIR-light absorption. In this work, we use gold (Au) nanorods to enhance the NIR-light absorption of Bi2WO6, a typical visible and novel NIR-light photocatalyst, thus the enhancement of its NIR-light photocatalytic and photoelectrochemical properties are achieved. This can be attributed to the surface plasmon resonance (SPR) effects and wide-range NIR light harvesting of the Au nanorods. The present work provides key guidelines for the improvement of NIR-light photocatalysts and could also help design and prepare novel photocatalysts. [ABSTRACT FROM AUTHOR]

Porous TiO2 films decorated with Bi2O3 nanoparticles are fabricated via alkali-hydrothermal of titanium (Ti) plate by varying the reaction time. The amorphous TiO2 is transformed into anatase after annealing the films at 500°C in air. The p-type Bi2O3 nanoparticles are successfully assembled on the surface of porous n-type TiO2 films through the ultrasonic-assisted successive ionic layer adsorption and reaction (SILAR) technique to form Bi2O3/TiO2 nanostructure by the two cycles. The obtained Bi2O3/TiO2 films are consisted of a well-ordered and uniform porous structure with an average pore diameter of about 100-200 nm containing homogeneously dispersed Bi2O3 nanoparticles of ~5 nm diameter. Moreover, the resultant composites present excellent photocatalytic performance toward methyl blue (MB) degradation under UV and visible light irradiation, which could be mainly ascribed to the enhanced light adsorption capacity of unique composite structure and the formation of p- n heterojunctions in the porous Bi2O3/TiO2 films. This research is helpful to design and construct the highly efficient heterogeneous semiconductor photocatalysts. [ABSTRACT FROM AUTHOR]

We present a rational design for the controllable synthesis of NiO/TiO 2 hollow microspheres (NTHMs) with Ti plate via a one-pot template-free synthesis strategy. Specifically, to enhance the formation of hollow microspheres, part of the titanium source is provided by the Ti plate. The hollow spherical NiO/TiO 2 particles possess unique microstructural characteristics, namely, a higher specific surface area (∼65.82 m 2 g −1 ), a larger mesoporous structure (∼7.79 nm), and hierarchical nanoarchitectures connected with mesopores within the shell (monodispersed size of ∼1 μm and shell thickness of ∼80 nm). In addition, as a cocatalyst for improved catalytic activity, the incorporated NiO nanoparticles with exposed high surface energy {110} facets displayed an outstanding performance. It has been proven that this facile nanostructure possesses remarkably high photoelectrochemical and photocatalytic activities. The main mechanism for enhancement of photocatalytic activity is attributed to the construction of p - n junctions with an inner electric field between TiO 2 and NiO, which can dramatically enhance the separation efficiency of the photogenerated electron-hole pairs. This strategy could be applied to fabricate mixed metal oxide hollow microspheres toward the photoelectrochemical catalysis. [ABSTRACT FROM AUTHOR]

Highlights: The 1T-WS2@TiO2@Ti3C2 photocatalyst is highly active for water splitting to produce hydrogen at 3409.8 μmol g−1 h−1. The Ti3C2 MXene and octahedral (1T) phase WS2 act pathways transferring photogenerated electrons. The biggest challenging issue in photocatalysis is efficient separation of the photoinduced carriers and the aggregation of photoexcited electrons on photocatalyst's surface. In this paper, we report that double metallic co-catalysts Ti3C2 MXene and metallic octahedral (1T) phase tungsten disulfide (WS2) act pathways transferring photoexcited electrons in assisting the photocatalytic H2 evolution. TiO2 nanosheets were in situ grown on highly conductive Ti3C2 MXenes and 1T-WS2 nanoparticles were then uniformly distributed on TiO2@Ti3C2 composite. Thus, a distinctive 1T-WS2@TiO2@Ti3C2 composite with double metallic co-catalysts was achieved, and the content of 1T phase reaches 73%. The photocatalytic H2 evolution performance of 1T-WS2@TiO2@Ti3C2 composite with an optimized 15 wt% WS2 ratio is nearly 50 times higher than that of TiO2 nanosheets because of conductive Ti3C2 MXene and 1T-WS2 resulting in the increase of electron transfer efficiency. Besides, the 1T-WS2 on the surface of TiO2@Ti3C2 composite enhances the Brunauer–Emmett–Teller surface area and boosts the density of active site. [ABSTRACT FROM AUTHOR]

Exposing high surface areas with porous materials and assembling heterostructures with chemical element doping represent a useful approach to producing high-performance photocatalysts. Porous TiB 2 -TiC/TiO 2 heterostructure, a new three-dimensional (3D) porous material with carbon and boron elements, was prepared in this study via alkali-assisted hydrothermal method followed by the in situ growth of porous TiB 2 -TiC material. The samples as-formed contain a wide variety of morphologies from nanosheet to sweetened roll, and exhibit dramatically enhanced photocatalytic activity for the degradation of methyl orange and rhodamine B compared to pure porous TiB 2 -TiC materials. The mechanisms for heterostructure formation and photocatalytic effect are analyzed to find that the heterostructures enhanced the separation of the photoinduced carriers, and that the morphological features of TiB 2 -TiC/TiO 2 heterostructures exert a significant influence on the photocatalytic degradation of organic pollutants. [ABSTRACT FROM AUTHOR]

Light harvesting and charge separation are both significant to the photocatalysis, but it is challenging to synchronously realize both in a single-component material. The surface coarsened TiO 2 nanobelts with TiO 2 (B)/anatase hetrophase junctions and large BET surface area are prepared via a hydrothermal/annealing method. The presence of surface coarsened nanobelt structure enhances the light absorption through reflection/refraction of light. The TiO 2 (B)/anatase hetrophase junctions can efficiently promote the separation of photoinduced electrons and holes pairs and therefore decrease the charge recombination. The large BET surface area provides abundant active sites for the absorption and diffusion of reactants. As a consequence, the obtained TiO 2 nanobelts exhibit an enhanced photocatalytic H 2 evolution activity at the optimal annealing temperature (450 °C) with Pt as co-catalysts (0.786 mmol h−1g−1), exceeding that of pure anatase TiO 2 nanobelts (TiO 2 nanobelts-600 °C, 0.265 mmol h−1g−1). Interestingly, TiO 2 nanobelts-450 °C still show a high hydrogen evolution rate of 0.601 mmol h−1g−1 in the absence of co-catalysts. Image 1 • TiO 2 nanobelts with TiO 2 (B)/anatase hetrophase junctions are prepared. • The surface coarsened nanobelt structure enhances the light absorption through reflection/refraction of light. • The TiO 2 (B)/anatase hetrophase junctions can efficiently promote the separation of photoinduced carriers. • TiO 2 nanobelts-450 °C are highly active for producing hydrogen at 0.786 mmol h−1g−1 with Pt as co-catalysts. • TiO 2 nanobelts-450 °C still show a high hydrogen evolution rate of 0.601 mmol h−1g−1 in the absence of co-catalysts. [ABSTRACT FROM AUTHOR]

Light harvesting and charge separation are both significant in the photocatalysis, but it is challenging to synchronously realize both in a single-component material. The novel porous TiO 2 nanoflowers (NFs) photocatalysts with stable bronze (TiO 2 (B))/anatase heterophase junctions and large pore sizes are prepared via a hydrothermal/annealing method. The presence of porous nanoflower structure enhances the light absorption through reflection/refraction of light. The stable TiO 2 (B)/anatase heterophase junctions can efficiently promote the separation of photoinduced electrons and holes pairs and therefore suppress the charge recombination. The large pore sizes provide multi-level channels for the absorption and diffusion of reactants. With the increase of annealing temperatures from 350 to 550 °C, the H 2 evolution activity is promoted. However, overhigh annealing temperature (650 °C) cause the broken of nanoflower structure and TiO 2 (B)/anatase heterophase junctions, thus inducing even decrease of H 2 evolution activity. As a consequence, the obtained TiO 2 NFs exhibit an enhanced photocatalytic H 2 evolution activity at the optimal annealing temperature (550 °C) with Pt as co-catalysts (5.013 mmol h−1g−1), exceeding that of TiO 2 NFs without annealing (0 mmol h−1g−1) and pure anatase TiO 2 NFs (TiO 2 NFs-650 °C, 4.722 mmol h−1g−1), respectively. Interestingly, TiO 2 NFs-550 °C still show a high hydrogen evolution rate of 4.317 mmol h−1g−1 in the absence of co-catalysts. Image 1 • TiO 2 nanoflowers with TiO 2 (B)/anatase heterophase junctions are prepared. • The porous nanoflower structure enhances the light absorption through reflection/refraction of light. • The TiO 2 (B)/anatase heterophase junctions can efficiently promote the separation of photoinduced carriers. • TiO 2 NFs-550 °C are highly active for producing hydrogen at 5.013 mmol h−1g−1 with Pt as co-catalysts. • TiO 2 NFs-550 °C still show a high hydrogen evolution rate of 4.317 mmol h−1g−1 in the absence of co-catalysts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Carbon modified graphitic carbon nitride was prepared by one-step pyrolysis of KF and melamine. • The photocatalytic activity in H 2 generation was investigated. • Highly improved photocatalytic H 2 evolution under visible light was realized. • Considerable apparent quantum yields were achieved. Abstract In this work, kapok fiber (KF), known as a versatile biomass, has been mixed with melamine to produce carbon modified graphitic carbon nitride (CCN) by one-step pyrolysis. The bio-char ribbon edges formed after the decomposition of KF act as the substrate for the epitaxial growth of CCN. The photocatalytic activity in hydrogen (H 2) generation from water splitting has been investigated. Nash Equilibrium from Game Theory has been firstly applied in the analysis of the H 2 generation rates among catalysts. The bio-char ribbon edges at the thin CN layers after carbon doping from KF decomposition improve the charge separation and transfer for the surface H 2 generation reaction. The CCN exhibits superior visible-light-driven photocatalytic activity and the H 2 evolution rate (18.89 μmol/h) is 67.5 times higher than that of the pristine CN (0.28 μmol/h). The apparent quantum yields are calculated to be 4.1%, 1.4%, 0.66% for monochromatic light λ = 420, λ = 470 and λ = 550 nm, respectively. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hierarchical TiO 2 nanotube with uniform carbon coatings is synthesized successfully. • The TiO 2 /C hierarchical nanotube exhibits the best photocatalytic activity under full solar spectrum light irradiation. • The incorporation of visible/NIR light active carbon coating with UV light responsive TiO 2 promote solar utilization. • The hierarchical nanotube can generate multiple reflections of incident light to promote an efficient light harvesting. • The generated carbon coatings on the surface of TiO 2 facilitate electron-hole separation. Abstract Smart architectures of TiO 2 are attracting increasing attention due to their outstanding properties in a broad range of fields. Herein, hierarchical TiO 2 nanotube with uniform carbon coatings is synthesized as the full solar spectrum photocatalytic materials for O 2 evolution by a facile solvothermal method. This unique structure consists of an interstitial hollow spaces and a functional nanotube shell assembled from two-dimensional (2D) nanosheets. By adjusting the types of solvents and reaction time, the morphologies of TiO 2 /C composites can be tuned to nanoparticles, nanorods, or hierarchical nanotubes. Among these morphologies, the TiO 2 / C hierarchical nanotube exhibits the best photocatalytic activity and favorable stability toward oxygen evolution from water oxidation under full solar spectrum light irradiation. The reason is attributed to the desirable incorporation of visible/near-infrared (NIR) light active carbon coating with UV light responsive TiO 2 for promoted solar energy utilization. Besides, the solvothermal step leads to hierarchical nanotube structures which can generate multiple reflections of incident light so as to promote an efficient light harvesting due to an enhanced specific surface area (244.4 m2 g−1) and light scattering ability. Moreover, the generated carbon coatings on the surface of TiO 2 facilitate electron-hole separation. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract A photocatalyst with good electron-transfer property and wide spectrum response is of great interest. Herein, visible/NIR-light-driven Ag 2 O nanoparticles (NPs) and UV/visible-responsive reduced TiO 2 nanosheets (TiO 2−x NSs) anchored onto reduced graphene oxide (rGO) forming Ag 2 O@rGO@TiO 2−x composites are synthesized in this study. The as-synthesized Ag 2 O@rGO@TiO 2−x composites exhibit a superior full solar spectrum (UV, visible and NIR) response, showing their potential for effective use of solar energy. Compared to single component (TiO 2 NSs and Ag 2 O NPs) or binary composites (Ag 2 O@TiO 2), Ag 2 O@rGO@TiO 2−x ternary composite has exhibited improved photocatalytic activity under UV, visible, NIR and nature sunlight irradiation and excellent photostability. The outstanding photocatalytic performance of Ag 2 O@rGO@TiO 2−x composites depends on three sides: firstly, synergistic effect among the reduced TiO 2 , Ag 2 O, and rGO improves the wide spectrum response ability; Secondly, Ag 2 O@rGO@TiO 2−x builds a Z-scheme structure, which promotes the separation of electron/hole pairs and retains prominent redox ability; Thirdly, the electrons of Ag 2 O are transferred to rGO to suppress the photo-corrosion of Ag 2 O during the photocatalytic process and the stability of Ag 2 O@rGO@TiO 2−x composite has been enhanced greatly. [ABSTRACT FROM AUTHOR]

Graphical abstract In this work, we developed a piezoelectric promoted full solar spectrum photocatalytic system by assembling full solar response Ag 2 O NPs on piezoelectric MoS 2 NFs. Abstract The separation of photoinduced electrons and holes can enhance the photocatalytic properties of photocatalysts. A piezoelectric field is created inside piezoelectric materials, such as ZnO and MoS 2 , by applying strain. The electrons and holes become separated under the driving force of the piezoelectric field. Here, we propose combining piezoelectric MoS 2 nanoflowers (NFs) and full solar response Ag 2 O nanoparticles (NPs) to form a MoS 2 @Ag 2 O heterostructure and achieve high efficiency full solar (UV, visible, and near-infrared) photocatalysis. Under both full solar light and ultrasonic excitation, the MoS 2 @Ag 2 O heterostructures can rapidly degrade methyl orange (MO) in aqueous solution. A built-in electric field is formed by the spontaneous polarization potential of the MoS 2 NFs during this process, and an ultrasonic wave as a driving force can consecutively change the potential created by the piezoelectric effect. Under light irradiation, electrons and holes are generated in the Ag 2 O NPs, and the photogenerated electrons and holes with opposite signs in the two Ag 2 O NPs at the two surfaces of the MoS 2 NFs, can be separated respectively, along the spontaneous polarized direction. Therefore, the piezoelectric effect-induced enhancement of carrier separation under ultrasonic excitation can improve the full solar photocatalytic performance of the MoS 2 @Ag 2 O heterostructures. [ABSTRACT FROM AUTHOR]

Effectively harvesting light to generate long-lived charge carriers to suppress the recombination of electrons and holes is crucial for photocatalytic reactions. Constructing the heterostructure and exposing the highly active facets have been regarded as powerful approaches to high-performance photocatalysts. In this paper, a three-dimensional (3D) double-heterostructured photocatalyst was constructed by connecting a TiO 2 -MoS 2 core-shell nanosheets (NSs) assembled on a graphite fiber (GF@MoS 2 -TiO 2 ) via a facile two-step hydrothermal method. The highly active {001} facets of TiO 2 NSs vertically grown on the GFs and uniformly ultrathin MoS 2 NSs on the surface of TiO 2 NSs (rich in active edge sites) afford high-efficiency photogeneration of electron-hole pairs under UV and visible light. Meanwhile, the carrier separation is substantially promoted by the Ohmic contact between TiO 2 NSs and the efficiently channeling electrons of zero-bandgap GFs, and the two-dimensional (2D) nanojunction with intimate and large contact interface between TiO 2 NSs and MoS 2 NSs. The improved charge separation and exposed active facets dramatically boost the photocatalytic degradation of methyl orange dye. [ABSTRACT FROM AUTHOR]

Based on energy band matching between RuO 2 and TiO 2 , the RuO 2 /TiO 2 nanobelt heterostructures are designed and fabricated. The formed heterostructures can efficiently enhance the separation of photogenerated electron-hole pairs and accelerate the transport of charges. Thanks to above-mentioned advantages, the RuO 2 /TiO 2 nanobelt heterostructures exhibit an improved photocatalytic performance compared with P25, TiO 2 , and RuO 2 under UV and visible light irradiation. Moreover, the nanopapers based on RuO 2 /TiO 2 nanobelt heterostructures have been prepared via a modified paper-making process. The paper-like porous RuO 2 /TiO 2 nanobelt heterostructures are applied in heterogeneous catalysis and present enhanced activity and selectivity for catalyzing aerobic oxidation of benzyl acohol. These results may provide a paradigm to fabricate and design the one-dimensional TiO 2 nanostructured surface heterostructures with high efficiency and performance. [ABSTRACT FROM AUTHOR]