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A probable mechanism of photocatalytic hydrogen evolution was summarized, where: (i) La, S-dual defects significantly improve the separation efficiency of photogenerated carrier and enhance the active sites; (ii) Co 3 S 4 nanoparticles with excellent photothermal properties can increase the temperature in a local area to reduce the reaction barrier and further accelerate carrier mobility; (iii) the Z-scheme band alignment enables more efficient charge transfer and strong redox ability. [Display omitted] Optimize the separation and transport mechanism of photogenerated carriers in heterojunction composites, and make full use of the active sites of each material are key factors to enhance photocatalytic activity. Herein, we successfully synthesize defective CdLa 2 S 4 @La(OH) 3 @Co 3 S 4 (CLS@LOH@CS) Z-scheme heterojunction photocatalysts through a facile solvothermal method, which show broad-spectrum absorption and excellent photocatalytic activity. La(OH) 3 nanosheets not only greatly increase the specific surface area of photocatalyst, but also can be coupled with CdLa 2 S 4 (CLS) and form Z-scheme heterojunction by converting irradiation light. In addition, Co 3 S 4 with photothermal properties is obtained by in-situ sulfurization method, which can release heat to improve the mobility of photogenerated carriers, and also be used as a cocatalyst for hydrogen production. Most importantly, the formation of Co 3 S 4 leads to a large number of sulfur vacancy defects in CLS, and thus improving the separation efficiency of photogenerated electrons and holes, and increasing the catalytic active sites. Consequently, the maximum hydrogen production rate of CLS@LOH@CS heterojunctions can reach 26.4 mmol g-1h−1, which is 293 times than pristine CLS (0.09 mmol g-1h−1). This work will provide a new horizon for synthesizing high efficiency heterojunction photocatalysts through switching the separation and transport modes of photogenerated carrier. [ABSTRACT FROM AUTHOR]

Ag/mesoporous black TiO2 nanotubes heterojunctions (Ag‐MBTHs) were fabricated through a surface hydrogenation, wet‐impregnation and photoreduction strategy. The as‐prepared Ag‐MBTHs possess a relatively high specific surface area of ≈85 m2 g−1 and an average pore size of ≈13.2 nm. The Ag‐MBTHs with a narrow band gap of ≈2.63 eV extend the photoresponse from UV to the visible‐light and near‐infrared (NIR) region. They exhibit excellent visible‐NIR‐driven photothermal catalytic and photocatalytic performance for complete conversion of nitro aromatic compounds (100 %) and mineralization of highly toxic phenol (100 %). The enhancement can be attributed to the mesoporous hollow structures increasing the light multi‐refraction, the Ti3+ in frameworks and the surface plasmon resonance (SPR) effect of plasmonic Ag nanoparticles favoring light‐harvesting and spatial separation of photogenerated electron–hole pairs, which is confirmed by transient fluorescence. The fabrication of this SPR‐enhanced visible‐NIR‐driven Ag‐MBTHs catalyst may provide new insights for designing other high‐performance heterojunctions as photocatalytic and photothermal catalytic nanomaterials. Responding strongly: Ag/mesoporous black TiO2 hollow nanotube heterojunctions with wide‐spectrum response (≈2500 nm) were fabricated through a wet‐impregnation and photoreduction strategy. They exhibit excellent visible‐NIR‐driven photocatalytic and photothermal catalytic performance and long‐term stability, due to the synergistic effect of efficient surface hydrogenation, hollow structured TiO2, formation of heterojunctions, and surface plasmon resonance of Ag. [ABSTRACT FROM AUTHOR]

It is desirable to develop an efficient visible-light-driven photocatalyst for practical application to degrade highly-noxious pollutants. Herein, the hydrogenation hierarchical flower-like Bi 2 MoO 6 hollow spheres (H-BMO-X, where X represents the different hydrogen calcination temperatures) have been successfully fabricated by a solvothermal-surface hydrogenation process. The as-prepared nano-photocatalyst H-BMO-300 clearly exhibits a photocatalytic reaction apparent rate constant k for high-noxious pollutants by ∼3-times higher than pristine Bi 2 MoO 6 . Moreover, the resultant H-BMO-300 sample with a narrow bandgap of ∼2.70 eV possesses surface oxygen vacancy defects. Based on the scanning Kelvin probe and surface photovoltage spectroscopy, it is deduced that the photocatalytic activities are attributed to the surface oxygen vacancy of H-BMO-X favoring the electron-hole pair’s separation. The enhanced photocatalytic performance can be ascribed to the synergistic effect of surface defects favoring efficient electron-hole separation and the hollow hierarchical structure benefiting the utilization of visible light, which provides more surface-active sites. This work provides a viable route to perceptibly enhance the photocatalytic activities of H-BMO-300 for environmental remediation with good mineralization properties. [ABSTRACT FROM AUTHOR]

The solar-light-harvesting and separation of nanostructured photocatalysts in slurry systems are key issues in fields of photocatalysis. Herein, magnetic Fe 2 O 3 /mesoporous black TiO 2 hollow sphere heterojunctions (M-Fe 2 O 3 /b-TiO 2 ) are fabricated through wet-impregnation and surface hydrogenation strategy, which show wide-spectrum response and magnetic separation. The decreased specific surfaces, pore sizes and pore volumes from ∼80 to 67 m 2 g −1 , ∼12 to 10.3 nm, and ∼0.20 to 0.16 cm 3 g −1 , respectively, all confirm the efficient loading of magnetic Fe 2 O 3 . The M-Fe 2 O 3 /b-TiO 2 with narrow bandgap of ∼2.41 eV extends the photoresponse from UV to near infrared region and exhibits excellent solar-driven photocatalytic degradation performance and long-term stability for complete mineralization methyl orange and high-toxic herbicide metribuzin. The photocatalytic reaction apparent rate constant k for metribuzin is ∼ 9 times higher than that of pristine TiO 2 under AM 1.5 irradiation. Especially for single-wavelength of 950 nm, the degradation ratio is up to 4%. The enhancement is attributed to Ti 3+ and magnetic Fe 2 O 3 with narrow bandgap facilitating solar-light-harvesting, the hollow structure benefiting mass transport, and the heterojunctions favoring the spatial separation of photogenerated electron-hole pairs. The magnetic separation is conducive to recycle of photocatalysts, which favors practical applications in environment. [ABSTRACT FROM AUTHOR]

Uniform black TiO2 nanothorns/graphene/black TiO2 nanothorns sandwichlike nanosheets (denoted as G@BTN) are fabricated through facile solvothermal approach and subsequent surface hydrogenation, in which the black TiO2 nanothorns vertically grow on the surface of two sides of graphene and form the sandwichlike structure. The rational control of hydrolysis and condensation of Ti precursors results in a uniform coating of amorphous TiO2 seeds, which then vertically grow in TiO2 nanothorns. After surface hydrogenation, the resultant G@BTN materials, with uniform sandwichlike configuration and narrow band gap of approximately 2.81 eV, can extend the photoresponse from the ultraviolet to the visible-light region and exhibit an excellent solar-driven photocatalytic performance for the degradation of the highly toxic pesticide atrazine (99 %). The first-order rate constant ( k) of G@BTN (0.863 h−1) is about three times as high as that of black TiO2 nanothorns (0.287 h−1), which implies the significant role of the introduction of graphene for improving the photocatalytic performance. The high solar-driven photocatalytic performance is ascribed to the formed Ti3+ in frameworks and surface disorders enhancing the absorption of solar light, and the sandwichlike structure favoring the separation and transportation of photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simple synthesis for ultrathin d Zni -ZIS nanosheets with interstitial zinc (Zn i) doping. • Ultrathin structure and large layer spacing of d Zni -ZIS nanosheets provide adequate active sites. • Improved charge separation efficiency by Zn i doping. • Zn i doping narrows the bandgap and extends light absorption. • High visible-light-driven overall water splitting performance. It is urgent to develop photocatalysts with high efficiency and simple preparation for overall water splitting. Herein, we successfully fabricate ultrathin ZnIn 2 S 4 nanosheets with in-situ interstitial zinc doping and short-range disordered structure (d Zni -ZIS) by one-step solvothermal method with magnetic stirring, which can realize overall water splitting without cocatalysts under visible light irradiation. In-situ interstitial Zn (Zn i) doping can not only induce electrostatic potential difference to accelerate the separation efficiency of photogenerated carriers, but also broaden layer spacing and create short-range disordered structure in nanosheets. Moreover, the disordered regions possess abundant active sites and adjustable electronic configurations, which increase the surface carrier density and enable adequate charges for surface reaction. Consequently, the average photocatalytic H 2 and O 2 evolution rates of the resultant ultrathin d Zni -ZIS nanosheets achieve 42.8 and 19.1 µmol g-1h−1 under visible-light irradiation, as well as an apparent quantum yield (AQE) of 1.51% at 420 nm without noble-metal cocatalysts. [ABSTRACT FROM AUTHOR]

• A defective ZIS@NOH/NO photocatalyst with the p-n and Z-scheme heterojunction was synthesized successfully. • The in-situ generated NiO as a cocatalyst provides excellent photothermal effect. • ZIS@NOH/NO heterojunction exhibit exciting enhanced photocatalytic CO 2 reduction activity and selectivity. • Multiple mechanisms collaborate to regulate carrier transport paths. Photocatalytic reduction of CO 2 into valuable chemicals has been considered as a sustainable and environmentally friendly technology, which can simultaneously alleviate the energy crisis and environmental problems that have puzzled people for a long time. Herein, we successfully synthesize defective ZnIn 2 S 4 @Ni(OH) 2 /NiO (ZIS@NOH/NiO) Z-scheme heterojunction photocatalysts through solvothermal and low-temperature calcination strategies. The loading of Ni(OH) 2 nanosheets can increase the specific surface area of photocatalyst, and form Z-scheme heterojunction with ZIS to improve the utilization of photogenerated electrons. It is worth noting that during the low-temperature calcination process, Ni(OH) 2 is partially converted into NiO, and a large number of metal defects are formed, which reduces the bandgap of Ni(OH) 2 and shows visible light response. In addition, the generated black defective NiO with full spectrum response and good photothermal effects can accelerate the migration of photogenerated carriers and reduce the catalytic reaction barrier of CO 2. Consequently, the prepared ZIS@NOH/NiO exhibits a high yield (133.74 μmol g−1) and selectivity (86.2 %) for CO 2 to CH 4 , which almost is 3.2 and 11.1 times than those of ZnIn 2 S 4 @Ni(OH) 2 and ZnIn 2 S 4 , respectively. Furthermore, in-situ Fourier transform infrared spectroscopy (FTIR) analysis reveal the effective adsorption of CO 2 on the ZnIn 2 S 4 @Ni(OH) 2 /NiO surface and the high selectivity of CH 4. This work will provide meaningful prospects for designing a carbon dioxide reduction photocatalyst with high conversion and selective. [ABSTRACT FROM AUTHOR]

Ag nanoparticle-decorated self-floating porous black TiO 2 foams (Ag-FBTFs) are fabricated by facile wet-impregnation and high-temperature surface hydrogenation strategy, utilizing self-floating porous black TiO 2 foams (FBTFs) with 3D macro-mesoporous architectures as hosts. The composites are evidently investigated by X-ray diffraction (XRD), Raman, N 2 adsorption, diffuse reflectance spectroscopy (DRS), transmission electron microscope (TEM), scanning electron microscopy (SEM), scanning Kelvin Probe (SKP), surface photovoltage spectroscopy (SPS) and photoluminescence (PL). The results show that the small Ag nanoparticles with diameter of 3–4 nm are decorated on the surface of FBTFs uniformly, which extend the photoresponse to visible-light region and show obvious surface plasmon resonance (SPR). The Ag-FBTFs exhibit excellent solar-driven photocatalytic performance for complete mineralization of some high-toxic organic contaminants. The enhancement can be attributed to the 3D macro-mesoporous networks facilitating the diffusion of reactants and products, the floating feature and small Ag nanoparticle-decoration favoring light-harvesting and spatial separation of photogenerated electron-hole pairs due to SPR effect. This novel SPR-enhanced solar-driven floating photocatalyst will have potential application in fields of natural environment. [ABSTRACT FROM AUTHOR]

The recycle and light-harvesting of powder photocatalysts in suspended system are bottlenecks for practical applications in photocatalysis. Herein, we demonstrate the facile synthesis of self-floating amphiphilic black TiO 2 foams with 3D macro-mesoporous architectures through freeze-drying method combined with cast molding technology and subsequent high-temperature surface hydrogenation. Ethylenediamine plays bifunctional roles on acid-base equilibrium and “concrete effect” on stabilizing the 3D macro-mesoporous networks against collapsing, which also inhibit the phase transformation from anatase-to-rutile and undesirable grain growth during hydrogenation at 600 °C. The resultant black TiO 2 foams, which can float on the water, extend the photoresponse from UV to visible-light region and exhibit excellent solar-driven photocatalytic activity and long-term stability for complete mineralization of floating insoluble hexadecane and some typical pesticides. Especially for floating contaminant hexadecane, the photocatalytic reaction apparent rate constant k is ∼7 times higher than that of commercial Degussa P25 under AM 1.5 irradiation. This enhancement is attributed to the 3D macro-mesoporous networks facilitating mass transport, the super amphiphilicity benefiting rapid adsorption, the floating feature and Ti 3+ in frameworks favoring light-harvesting and spatial separation of photogenerated electron-hole pairs. The novel self-floating photocatalyst will have real practical applications for mineralizing floating contaminants in natural environment. [ABSTRACT FROM AUTHOR]