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The ternary 3D ordered macroporous (3DOM) heterojuncted nanocomposites (platinum/bismuth molybdate/3DOM TiO2: 3DOM‐Pt/Bi2MoO6/TiO2) are designed and synthesized as multifunctional platform for photocatalytic dye degradation, photoelectrocatalytic (PEC) water splitting, and thermal‐catalytic toluene decomposition with high performance. A series of structural, optical, and electronic characterizations demonstrates that the remarkably improved photocatalytic degradation and PEC water splitting activities are attributed to the combined effects of enhanced light harvesting, abundant reactive sites, facile reactants transfer, and efficient charges–holes pair separation. Through optimizing the loading amounts of Pt and Bi2MoO6, it is found that the 1%Pt/10%Bi2MoO6/TiO2 nanocomposite exhibits the highest photocatalytic Rhodamin B (RhB) degradation rate and PEC water splitting activity, which are 10 and 2.2 times higher than that of the titania photonic crystal (PC‐TiO2) photocatalyst, respectively. This work clearly illustrates that the ternary photocatalyst with 3DOM structure and intimate heterostructure can significantly facilitate the transfer of reaction intermediates and the separation of photogenerated carriers. Considering its unique 3DOM structure and excellent photocatalytic/PEC performances, the ternary nanocomposite has been used in catalytic toluene decomposition and inspiringly shows high efficiency, being very promising in thermocatalytic applications. This work provides new solutions in developing new ternary nanocomposites for versatile applications in photocatalytic, photoelectrochemical, and catalytic fields. [ABSTRACT FROM AUTHOR]

A porous TiO2/BaTiO3 heterostructure composite has been developed as a polysulfide mediator for lithium–sulfur batteries. Superior electrochemical performance has been achieved, mainly attributed to the synergy of TiO2 and BaTiO3 with dual affinity to polysulfides from chemical and ferroelectric-induced polarization effects, and enhanced redox kinetics propelled by the TiO2/BaTiO3 heterojunctions. [ABSTRACT FROM AUTHOR]

Our whole-cell biocatalyst with a polydopamine nanocoating shows high catalytic activity (5 times better productivity than the native cell) and reusability (84% of the initial yield after 5 batches, 8 times higher than the native cell) in asymmetric reduction. It also integrates with titania, silica, and magnetic nanoparticles for multi-functionalization. [ABSTRACT FROM AUTHOR]

Structure-forming processes leading to biominerals are well worth learning in pursuit of new synthetic techniques. Strategies that attempt to mimic nature in vitro cannot replace an entire complex natural organism, requiring ingenuity beyond chemists′ hands. A 'bioprocess-inspired synthesis' is demonstrated for fabrication of N-doped TiO2 materials at ambient temperature by direct implantation of precursor into living mussels. The amorphous precursor transforms into N-doped anatase TiO2 with a hierarchical nanostructure. Synthetic TiO2 exhibits high phase stability and enhanced visible-light photocatalytic activity as a result of modifications to its band gap during in vivo mineralization. Intracellular proteins were found to be involved in TiO2 mineralization. Our findings may inspire material production by new synthetic techniques, especially under environmentally benign conditions. [ABSTRACT FROM AUTHOR]

A simple one-step hydrothermal reaction among TiO2 powders and alkaline solution has been developed to synthesize low-dimensional titanate nanostructures. The morphologies of the obtained nanomaterials depend on the process parameters: the structure of raw material, the nature and concentration of alkaline solution, reaction temperature and time, which suggests that the nanostructure synthesis could be controllable. Trititanate nanotubes with the diameters of about 10 nm were synthesized via the hydrothermal reaction of TiO2 crystals of either anatase or rutile phase and NaOH solution in the temperature range of 100–160 °C. Nanofibers with an interlinked structure were formed when amorphous TiO2 or commercial TiOSO4 was treated with NaOH at 100–160 °C. Pentatitanate nanoribbons with high aspect ratio were obtained by autoclaving of either crystalline or amorphous TiO2 in NaOH solution at the temperature above 180 °C. Octatitanate nanowires with the diameters of 5–10 nm were prepared from TiO2 particles treated with KOH solution. These nanostructures were analyzed by a range of methods including powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX) and infrared spectroscopy (IR). [Copyright &y& Elsevier]

In this work, the activity of bimetallic Pd-Au doped hierarchically structured titania catalysts has been investigated in the total oxidation of toluene. In earlier works, doping titania with group Vb metal oxides ensured an increased catalytic performance in the elimination of VOC molecules. A synergy between gold and palladium loaded at the surface of titania supports provided better performances in VOC oxidation reactions. Therefore, the main focus in this work was to investigate the durability of the prepared catalysts under long time-on-stream periods. Vanadium-doped catalysts showed a stable activity throughout the whole 110 h test, whereas, surprisingly, niobium-doped catalysts presented a cycle-like activity while nevertheless maintaining a high performance in toluene elimination. Operando Diffuse Reflectance Infrared Fourrier Transform spectroscopy (DRIFT) experiments revealed that variations in the presence of OH radicals and the presence of carbonaceous compounds adsorbed at the surface of spent catalysts varies with the occurrence of oscillations. X-ray Photoelectron Spectroscopy (XPS) results show that interactions between the material and the active phase provided extra amounts of mobile oxygen species and participated in easing the reduction of palladium. An enhanced redox reaction scheme is thus obtained and allows the occurrence of the cyclic-like performance of the catalyst. [ABSTRACT FROM AUTHOR]

Structure-forming processes leading to biominerals are well worth learning in pursuit of new synthetic techniques. Strategies that attempt to mimic nature in vitro cannot replace an entire complex natural organism, requiring ingenuity beyond chemists′ hands. A 'bioprocess-inspired synthesis' is demonstrated for fabrication of N-doped TiO2 materials at ambient temperature by direct implantation of precursor into living mussels. The amorphous precursor transforms into N-doped anatase TiO2 with a hierarchical nanostructure. Synthetic TiO2 exhibits high phase stability and enhanced visible-light photocatalytic activity as a result of modifications to its band gap during in vivo mineralization. Intracellular proteins were found to be involved in TiO2 mineralization. Our findings may inspire material production by new synthetic techniques, especially under environmentally benign conditions. [ABSTRACT FROM AUTHOR]

The 3DOM TiO 2 -Au-CdS inverse opal photonic crystal structure is designed for visible-light hydrogen production, exhibiting extremely enhanced photocatalytic activity via coupling bifunctional SPR effect and electron transfer of Au NPs with slow photon effect. [Display omitted] • The ternary TiO 2 -Au-CdS (TAC) photocatalysts have been designed to couple the bifunctional Au NPs with slow photon effect. • A two electron transfer paths model is proposed in the ternary TAC photocatalysts. • Finite-difference time-domain (FDTD) simulations are used to reveal the size effect of Au NPs. • The ternary TAC-10 photocatalyst with ~ 10 nm Au NPs demonstrates the highest hydrogen evolution rate under visible-light. Gold nanoparticles (Au NPs) with surface plasmonic resonance (SPR) effect and excellent internal electron transfer ability have widely been combined with semiconductors for photocatalysis. However, the in-depth effects of Au NPs in multicomponent photocatalysts have not been completely understood. Herein, ternary titanium oxide-gold-cadmium sulfide (TiO 2 -Au-CdS, TAC) photocatalysts, based on hierarchical TiO 2 inverse opal photonic crystal structure with different Au NPs sizes have been designed to reveal the SPR effect and internal electron transfer of Au NPs in the presence of slow photon effect. It appears that the SPR effect and internal electron transfer ability of Au NPs, depending on their sizes, play a synergistic effect on the photocatalytic enhancement. The ternary TAC-10 photocatalyst with ~ 10 nm Au NPs demonstrates an unprecedented hydrogen evolution rate of 47.6 mmolh-1g−1 under visible-light, demonstrating ~ 48% enhancement comparing to the sample without slow photon effect. In particular, a 9.83% apparent quantum yield under 450 nm monochromatic light is achieved for TAC-10. A model is proposed and finite-difference time-domain (FDTD) simulations reveal the size influence of Au NPs in ternary TAC photocatalysts. This work suggests that the rational design of bifunctional Au NPs coupling with slow photon effect could largely promote hydrogen production from visible-light driven water splitting. [ABSTRACT FROM AUTHOR]

Abstract: Platinum catalysts supported on hierarchically porous TiO2 modified by niobium have been synthesized, characterized and tested for the complete oxidation of n-butanol. It was found that after Nb addition to titania, the hierarchical porous structure (meso- and macropores) was maintained. The anatase titania crystallite size decreased with Nb content which was consistent with the specific surface area increase (>160m2 g−1), even after calcination at 400°C. The incorporation of niobium into Pt/TiO2 catalysts led to a significant increase in catalytic activity in comparison with catalyst without niobium addition at a relative low temperature (≈100°C). Nb incorporation promoted the formation of reduced platinum species and resulted also in the formation of very easily reducible species (Pt2+ and Ti4+ in the vicinity). As a result, the activity at 100°C of Pt/5%Nb–TiO2 catalyst was 4 times higher than for Nb-free Pt/TiO2 catalyst. [Copyright &y& Elsevier]

Mesoporous titania materials with a novel macroporous structure have been synthesized by a one-step simple method in the presence of poly(ethylene oxide) surfactant. The three-dimensional, bicontinuous macroporous structures are in the interiors of the mesoporous titania particles with a uniform pore size gradient. The mesopores are disordered, wormhole-like, formed by the agglomeration of titania nanoparticles with anatase phase. The mesopore size can be modified from microporous to mesoporous range by tuning the synthesis time. The formation mechanism of the macro-mesostructured titanias is proposed. [Copyright &y& Elsevier]

Hollow microspheres of mesoporous titania with a thin shell of anatase structure have been prepared by a simple procedure of surfactant poly(ethylene oxide) assisted nanoparticle assembly in nonaqueous system. A high surface area of 378 m2/g and pore volume of 0.34 cm3/g was obtained in the as-prepared sample with pore size of 2.6 nm. A large number of surface hydroxyl groups and a reduced band gap were found, which should be significant for multi-functionalisation of the surface and photocatalysis applications. A formation mechanism of hollow microspheres was proposed. [Copyright &y& Elsevier]

Thin titanium oxide nanoribbons with a thickness of several nanometers and a width of 30–200 nm have been synthesized hydrothermally via the reaction of TiO2 particles and NaOH solution. Either amorphous TiO2 gel or crystalline anatase or a mixture of anatase and rutile can be used as the raw material. The typical lengths of nanoribbons are in the range of several micrometers to several tens of micrometers. The growth of nanoribbons is along the [0 0 1] direction of the anatase structure. [Copyright &y& Elsevier]

Abstract A theoretical investigation of optical proprieties of three nanostructures such as BiOV 4 /3DOM TiO 2 , ZnO/3DOM TiO 2 and BiOV 4 /3DOM ZnO has been presented and discussed. The study based on a one band effective mass approximation model was developed to calculate the charge carrier energies on various parameters of nanostructures including their size. We computed the optical properties for both spherical BiVO 4 and ZnO nanoparticles incorporated in the three dimensionally ordered macroporous inverse opal TiO 2 nanocomposites (3DOM-TiO 2). At first and by solving a three dimension Schrödinger equation we calculated the dependence of charge carriers energies on the size of nanoparticles. Then we investigated the variation of the excitonic energy of BiOV 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiOV 4 /3DOM-ZnO as function of the radius of these nanostructures into taken account the effects of dielectric and coulomb interaction between charge carriers. We showed that the radiative recombination lifetime is enhanced with decreasing BiVO 4 and ZnO quantum dots (QDs) size. It was found that as the size of the dot is reduced the confinement of charge carriers and the optical gap are increased. The optical gap of the ZnO/3DOM-TiO 2 is larger than both BiOV 4 /3DOM-TiO 2 and BiOV 4 /3DOM-ZnO especially for small radius. It was also found that radiative life time in the BiOV 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiOV 4 /3DOM-ZnO increased by increasing the radius of these nanostructures. In addition, we have also showed that, the radiative lifetime in the ZnO/3DOM-TiO 2 nanostructure is less than both BiOV 4 /3DOM-TiO 2 and BiOV 4 /3DOM-ZnO nanostructures. Finally, we have studied and discussed the Auger process in BiOV 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiOV 4 /3DOM-ZnO nanostructures. At first, we have showed that the auger process is important when the radiuses of nanostructures are less than 2 nm. Then we have also showed that this process is more important for ZnO/3DOM-TiO 2 compared to the other nanostructures. Graphical abstract We focus our theoretical study on the radiative and Auger recombination lifetime in BiVO 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiVO 4 /3DOM-ZnO nanocomposites. Image 1 Highlights • Novel nanocompsites BiVO 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiVO 4 /3DOM-ZnO has been realized for the photocatalysis. • We calculate the radiative recombination lifetime in BiVO 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiVO 4 /3DOM-ZnO nanocomposites. • We calculate the Auger recombination lifetime in BiVO 4 /3DOM-TiO 2 ZnO/3DOM-TiO 2 and BiVO 4 /3DOM-ZnO nanocomposites. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel ternary ZnO/BiVO 4 /3DOM TiO 2 nanocomposites are synthesized. • Ternary ZnO/BiVO 4 /3DOM TiO 2 nanocomposites exhibit enhanced catalytic activity. • The cascade electronic band structure in ternary nanocomposites leads to the enhanced photocatalytic performance. • Coupling semiconductors with suitable energy levels is favorable to improve the efficiency of induced light. Abstract Ternary zinc oxide/bismuth vanadate/three-dimensional ordered macroporous titanium dioxide (ZnO/BiVO 4 /3DOM TiO 2) heterojuncted nanocomposites with cascade electronic band structures were successfully designed and synthesized for visible light photodegradation of two different molecules: Rhodamine B (RhB) and Tartrazine. The photocatalytic active species have been investigated by using electron scavenger (AgNO 3) and hole scavenger (Triethanolamine: TEOA). The band edge positions of each component in tenary nanocomposites have been measured by using photoelectrochemical Mott-Schottky method and valence band XPS (VB-XPS) spectroscopy. Within the heterojunction, charges are favorably and spatially separated through the gradient potential at the interfaces. This largely suppresses the recombination of photogenerated electrons and holes. Furthermore, 3DOM inverse opal structure is beneficial for high diffusion efficiency and highly accessible surface area of reactants and light and multiple scattering for light harvesting. Consequently, these heterojuncted nanocomposites exhibit highly enhanced photocatalytic performance compared with pure BiVO 4 nanostructure, and binary BiVO 4 /3DOM TiO 2 , ZnO/BiVO 4 nanocomposites. A detailed mechanism of charge transfer is proposed for these ternary ZnO/BiVO 4 /3DOM TiO 2 nanocomposites on the basis of a large series of spectroscopic and photocatalytic results. Our work demonstrates clearly that coupling multicomponent semiconductors with different energy levels of conduction and valence bands can significantly increase the photogenerated charge carriers through the efficient charge separation across their multiple interfaces. This work gives some new ideas on developing new visible light responsive nanocomposites for highly efficient solar energy utilization. [ABSTRACT FROM AUTHOR]

Hierarchical nanosheet-constructed porous TiO 2 -B has been successfully synthesized by a facile hydrothermal route using a hybrid precursor as in situ template. The resulting TiO 2 -B material with a high specific surface area of ∼154 m 2 /g manifests superior Li storage performance due to the synergy of TiO 2 -B polymorph, nanosheet morphology, and hierarchical interconnected porous framework. [ABSTRACT FROM AUTHOR]

A series of BiVO 4 /3DOM TiO 2 nanocomposites have been synthesized and their photocatalytic activity was investigated under visible light irradiation using the RhB dye as model pollutant molecule in an aqueous solution. The effect of the amount of BiVO 4 as visible light sensitizer on the photocatalytic activity of BiVO 4 /3DOM TiO 2 nanocomposites was highlighted. The heterostructured composite system leads to much higher photocatalytic efficiencies than bare 3DOM TiO 2 and BiVO 4 nanoparticles. As the proportion of BiVO 4 in BiVO 4 /3DOM TiO 2 nanocomposites increases from 0.04 to 0.6, the photocatalytic performance of the BiVO 4 /3DOM TiO 2 nanocomposites increases and then decreases after reaching a maximum at 0.2. This improvement in photocatalytic perfomance is related to 1) the interfacial electron transfer efficiency between the coupled materials, 2) the 3DOM TiO 2 inverse opal structure with interconnected pores providing an easy mass transfer of the reactant molecules and high accessibility to the active sites and large surface area and 3) the effect of light sensitizer of BiVO 4 . Intensive studies on structural, textural, optical and surface properties reveal that the electronic interactions between BiVO 4 and TiO 2 lead to an improved charge separation of the coupled BiVO 4 /TiO 2 system. The photogenerated charge carrier densities increase with increasing the BiVO 4 content, which acts as visible light sensitizer to the TiO 2 and is responsible for the enhancement in the rate of photocatalytic degradation. However, the photocatalytic activity is reduced when the BiVO 4 amount is much higher than that of 3DOM TiO 2 . Two reasons could account for this behavior. First, with increasing BiVO 4 content, the photogenerated electron/hole pairs are accumulated at the surface of the BiVO 4 nanoparticles and the recombination rate increases as shown by the PL results. Second, decreasing the amount of 3DOM TiO 2 in the nanocomposite decreases the surface area as shown by the BET results. Moreover, the poor adsorptive properties of the BiVO 4 photocatalyst also affect the photocatalytic performance, in particular at higher BiVO 4 content. The present work demonstrates that BiVO 4 /3DOM TiO 2 is a very promising heterojunction system for visible light photocatalytic applications. [ABSTRACT FROM AUTHOR]

Three dimensionally ordered macroporous inverse opal TiO 2 nanocomposites decorated by ZnO quantum dots (ZnO QDs@3DOM TiO 2 ) with an intimate contact were successfully synthesized using the sol-gel technique and characterized in terms of structure, porosity, chemical composition and optical properties. The photocatalytic activity of ZnO QDs@3DOM TiO 2 nanocomposites with different ZnO QDs amounts was evaluated in the aqueous phase of dye pollutant molecules and compared with the state-of-the-art 3DOM TiO 2 and P25 photocatalysts. The symbiotic effect of ZnO QDs and 3DOM photonic structure on the light absorption and further on the photocatalytic activity of the nanocomposites was observed. The sample with the highest ZnO QDs amount exhibits extraordinarily high photocatalytic activity, which is attributed to firstly, the formation of an intimate junction between the two semiconductors, hence favoring the separation of photo-introduced electron–hole pairs in ZnO-TiO 2 photocatalyst, and, secondly, to the quantum size effect (QSE). The QSE results in an increase in the width of the forbidden electronic band, which increases the energy of electrons (holes) in the conduction (valence) and particularly leads to the displacement of the conduction band potentials of ZnO to more negative energy values compared to TiO 2 . Thanks to the heterojuction formed between ZnO QDs and 3DOM TiO 2 , the energy difference between conduction bands of both semiconductors acts as a driving force for rapid electron/hole transfer between the coupled materials. Due to the extremely short diffusion time, the lifetime of photogenerated charge carriers is extended and the effectiveness of reduction and oxidation process is increased with faster reaction kinetics. Increasing the amount of ZnO QDs can boost the photocatalytic activity. On the other hand, 3DOM photonic structure of TiO 2 with its open meso-macroporosity can facilite the diffusion of dye molecules and light propagation. This first successful example of symbiose of a series of physical effects can open a new window for solar energy conversion by the synergitic association of QSEs, photonic effect and other effects such as plasmonic effects, in one solid material to develop highly efficient solar light havesting system to enhance solar energy conversion effeciency for photocatalysis and photovoltaics. [ABSTRACT FROM AUTHOR]

Porous TiO 2 urchins have been synthesized by a hydrothermal route using TiO 2 /oleylamine as precursors with subsequent ion-exchange and calcination. The resultant material consists of porous spherical cores and nanochains-constructed shells with straight channels. Electrochemical measurements indicate the TiO 2 urchins deliver superior lithium storage capability in terms of high capacity (206.2 mA h g −1 at 0.5 C), superior rate performance (94.4 mA h g −1 at 20 C) and stable cycling stability (94.3% capacity retention over 1000 cycles at 10 C versus the third cycle). Such performance enhancement is mainly due to the increased electrode/electrolyte contact interface, reduced Li + diffusion pathways and improved mass transfer of electrolyte in the unique 3D interconnected hierarchical network. In addition, ex-situ XRD, SEM and TEM analyses further reveal high structure integrity of the porous TiO 2 urchins during the electrochemical lithiation, leading to enhanced lithium storage stability. Moreover, we detected that some anatase nanocrystals evolved into electrochemically inactive Li 1 TiO 2 dots (∼10 nm in size) during long-term electrochemical cycling. Our findings provide more insights for better understanding of the structure evolution and capacity decay mechanism in porous TiO 2 nanostructures. [ABSTRACT FROM AUTHOR]

A ternary photocatalyst TiO 2 -Au-CdS based on three-dimensionally ordered macroporous TiO 2 (3DOM TiO 2 ) was successfully prepared to enhance the light absorption, extend the light responsive region, reduce the recombination rate of charge carriers and promote the efficiency of water splitting H 2 evolution ultimately. The obtained 3DOM TiO 2 -Au-CdS powder has a pure anatase phase of TiO 2 and greenockite structured CdS according to the XRD results and TEM analysis. Au nanoparticles (AuNPs) and CdS were evenly distributed in the 3DOM structure which enhances H 2 -generation rate under visible light by improving light harvesting and utilizing its mass transfer facilitation. As a result, the hydrogen generation rate (1.81 mmol h −1 g −1 ) using 3DOM TiO 2 -Au-CdS photocatalyst under visible light irradiation was 13-fold higher than the binary 3DOM TiO 2 -CdS reference photocatalyst. Under ultraviolet-visible light, the photogenerated electrons in TiO 2 would be transferred to recombine with the holes of CdS and under visible light, electrons would move to the conduction band (CB) of TiO 2 from CdS via AuNPs. The two different types of internal electron-transfer process in the ternary photocatalyst under ultraviolet and visible light were proposed respectively and both would efficiently reduce the recombination rate of photogenerated electrons and holes thus stimulate H 2 evolution rate. The present work demonstrated an excellent example of the synergistic effect of the light absorption enhancement by 3DOM structure, the photosensitizing and electron reservoir effect of AuNPs and the reduction of recombination rate of charge carriers by CdS to highly promote the photocatalytic activity in water splitting reaction. [ABSTRACT FROM AUTHOR]

Highlights: [•] Continuous TiO2 inverse opal films by sol–gel method. [•] High stability of photonic crystal structures of TiO2 inverse opal films under high temperature treatment. [•] Highly enhanced photocatalytic activity of TiO2 inverse opal films. [•] Slow photon effect in photodegradation of dye pollutants in aqueous solution. [•] Light absorption enhanced and further highly enhanced photocatalytic performance by slow photon effect. [ABSTRACT FROM AUTHOR]

Highlights: [•] A fast microwave hydrothermal route is developed to prepare porous anatase spheres. [•] The TiO2 spheres are constructed of interconnected nanocrystals with wormlike pores. [•] The TiO2 spheres exhibit high Li ion storage capacity and good rate capability. [•] The Li ion storage property of TiO2 spheres varies with pore size and crystallinity. [ABSTRACT FROM AUTHOR]

Abstract: The photocatalytic activities of various hierarchically meso–macroporous titanias, obtained via a spontaneous self-formation process using titanium isopropoxide, have been investigated by comparing each materials’ capability to photodegrade Rhodamine B. Three synthesis routes have been developed to synthesize hierarchically meso–macroporous titania materials: (A) in water without and (B) with hydrothermal treatment and (C) in a surfactant Brij 56 aqueous solution with hydrothermal treatment, respectively. These results show that the introduction of surfactant Brij 56 and a hydrothermal treatment in the synthesis system greatly improve the crystallinity of the anatase phase in hierarchically meso–macroporous titanias and their thermal stability, resulting in a remarkable enhancement of their photocatalytic activity. Furthermore, the effect of calcination on hierarchically porous structure and their photocatalytic activity has also been investigated in detail. The properties of the products were characterized by XRD, SEM and N2 adsorption-desorption measurements. [Copyright &y& Elsevier]

[Display omitted] • Tuneable and controllable synthesis of gold nanoparticles onto TiO 2 by plasma synthesis. • Efficient degradation of toluene. • Sintering of gold nanoparticles after high-temperature exposition due to high mobility on TiO 2 surface. The development of environment-friendly, low-cost and efficient catalyst preparation processes has always been a major issue in the field of catalysis. Wet chemistry methods are often used but these techniques are not sustainable, as post waste solution treatment remains an important drawback. Here an innovative dry low-pressure plasma process for metal nanoparticles supported nanocatalysts preparation is reported. The solid metal and oxide support precursors are physically mixed and then exposed to a radiofrequency Ar/N 2 plasma discharge, leading to the precursor degradation and the subsequent nanoparticles generation, without pre- or post- preparation steps. The metal nanoparticle loading and the particle size of metal and oxide support can be easily tuned by changing the ratio of the precursor materials, making the process simple, versatile, highly efficient, and scalable. As a proof of concept, gold nanoparticles (Au NPs) supported on titanium dioxide (TiO 2) were prepared and tested as nanocatalysts for toluene (C 7 H 8) degradation at temperatures ranging from 25 to 450 °C. Up to 100% of C 7 H 8 conversion into CO 2 was achieved over the Au-TiO 2 nanocatalysts, demonstrating that this dry method is a very efficient way to prepare highly active nanocatalysts. [ABSTRACT FROM AUTHOR]

Abstract: The photocatalytic behavior in dye molecule degradation of highly ordered three dimensional macroporous titania inverse opals prepared by the polystyrene spheres templating method has been investigated. The sulfate impurity stemming from K2S2O8 used as initiator for the styrene polymerization and remaining in the final materials in a form of sulfate anions was found to strongly inhibit the photocatalytic process of titania inverse opals. The mechanism of the negative effect of sulfate anionic impurity has been studied by the theoretical calculations and the comparison of samples subject to a wash process or not, the artificial addition of sulfate anions to the reaction medium and cycle experiments of samples without the washing process. Raman spectroscopy confirmed that in TiO2 inverse opal structures, sulfate ions are present in divalent forms. However, in aqueous photocatalytic medium, monovalent hydrosulfate anions can also be present. Theoretical calculations on the interaction of sulfate (mono and divalent) anions and Rhodamine B (RhB) with TiO2 inverse opal indicated that the adsorption binding energy of divalent sulfate anions on the titania surface (168kcal/mol) is over four times as that of the Rhodamine B (36kcal/mol) in the photocatalytic system and that of hydrosulfate anions is around 53–57kcal/mol, still much higher than that of Rhodamine B. The strong adsorption of the anionic sulfate impurity on the surface of titania inverse opals would block the active sites and thus strongly affect the photocatalytic performance. A model of the negative action of sulfate anions has been proposed. This work leads to a new physic-chemical insight on the behavior of sulfate anions in the photocatalytic degradation of RhB and revealed that a single washing process to remove the impurity suggested significant promotion effect of the photocatalytic reaction without any surface modulations. This washing process dramatically suppressed the adsorption effect induced by the sulfate impurity and simplified the procedures, improving the photocatalytic performance. [Copyright &y& Elsevier]

Abstract: Mesoporous TiO2 with a hierarchically 3D dendrimeric nanostructure comprised of nanoribbon building units has been synthesized via a spontaneous self-formation process from various titanium alkoxides. These hierarchically 3D dendrimeric architectures can be obtained by a very facile, template-free method, by simply dropping a titanium butoxide precursor into methanol solution. The novel configuration of the mesoporous TiO2 nanostructure in nanoribbon building units yields a high surface area. The calcined samples show significantly enhanced photocatalytic activity and degradation rates owing to the mesoporosity and their improved crystallinity after calcination. Furthermore, the 3D dendrimeric architectures can be preserved after phase transformation from amorphous TiO2 to anatase or rutile, which occurs during calcination. In addition, the spontaneous self-formation process of mesoporous TiO2 with hierarchically 3D dendrimeric architectures from the hydrolysis and condensation reaction of titanium butoxide in methanol has been followed by in situ optical microscopy (OM), revealing the secret on the formation of hierarchically 3D dendrimeric nanostructures. Moreover, mesoporous TiO2 nanostructures with similar hierarchically 3D dendrimeric architectures can also be obtained using other titanium alkoxides. The porosities and nanostructures of the resultant products were characterized by SEM, TEM, XRD, and N2 adsorption–desorption measurements. The present work provides a facile and reproducible method for the synthesis of novel mesoporous TiO2 nanoarchitectures, which in turn could herald the fabrication of more efficient photocatalysts. [Copyright &y& Elsevier]

Abstract: Various hierarchical porous titania with high surface area over 600m2/g have been synthesized via a spontaneous self-formation process from titanium alkoxides by a water adjusting approach using acetonitrile as reaction medium. The reactivity of metal alkoxides and the water content in acetonitrile medium on the resultant structure have been investigated. The porosities of the products were characterized by SEM, TEM and N2 adsorption–desorption measurements. The observation on the evolution of porous structure with increasing water content in reaction system is essential for a better understanding of hierarchical porous structure formation over different length scales by this self-formation process. The creation of macro/micropores in photocatalytic titania materials has been found to enhance the photocatalytic activity due to both the action of macrochannels as light harvester and the easy diffusion effect of organic molecules. The present work shows clearly that hierarchically porous titania with the presence of macroporous structure and high surface area can be very efficient photocatalysts, suggesting their potential applications in water treatment as decontamination materials. [Copyright &y& Elsevier]

Abstract: Catalytic performances of nanostructured mesoporous TiO2–ZrO2 mixed oxides impregnated by Pd and/or Au were studied in toluene total oxidation in a fixed bed microreactor and with “operando” DRIFT. Mesoporous TiO2–ZrO2 mixed oxides with various Ti:Zr mole ratio of 80/20, 50/50 and 20/80, high surface areas were synthesised using a mixture of zirconium propoxide and titanium isoporopoxide as Zr and Ti sources and also CTMABr as surfactant. The new supports are impregnated by 0.5 or 1.5wt% of palladium and 1wt% of gold using impregnation and Deposition–Precipitation methods. The catalytic activity for the nanostructured mesoporous TiO2−–ZrO2 mixed oxides varies depending on the molar ratio of Ti:Zr and also for all series of the studied catalysts impregnated by Pd and/or Au, when the gold is loaded firstly the activity in toluene complete oxidation is higher than when Pd was deposited firstly (PdAu/TZ>1.5Pd/TZ>AuPd/TZ>Pd/TZ>Au/TZ>TZ). The highest activity of PdAu/TZ (80/20) can be related to the higher acid sites density of the support and also to the presence of a synergetic effect between palladium and gold. “Operando” DRIFT allowed following the VOCs oxidation but also suggesting an interaction between the adsorbed molecule and the catalyst which decreases when the activity for oxidation reaction increases. [Copyright &y& Elsevier]

The TiO 2 nanosheets constructed yolk-shell sulfur-TiO 2 (S@void@TiO 2) architecture with optimized inner voids demonstrates high-performance and ultralong-life for Li-S battery. [Display omitted] • Designing TiO 2 nanosheets constructed yolk-shell TiO 2 (S@void@TiO 2) nanostructure for Li-S battery. • Verifying intense chemical interaction via the hybridization of Li 1 s, S 2p and O 2p orbitals in S@void@TiO 2. • Optimizing the inner voids for volume expansion to guarantee the cathode integrity. • Improving the electrolyte wettability and Li+ kinetics in S@void@TiO 2. • Realizing high capacity and long cycle with a small capacity decay for Li-S battery. A TiO 2 nanosheets constructed yolk-shell architecture with tunable inner voids is designed and prepared as sulfur host for high-performance and ultralong-life Li-S battery. With the integration of TiO 2 nanosheets to form yolk-shell sulfur-TiO 2 (S@void@TiO 2) architecture with controllable inner voids, the S@void@TiO 2 composite with optimized inner voids provides sufficient contacting sites to improve the utilization of insulating sulfur and allows sulfur to freely expand without destroying the electrode. In particular, the density functional theory (DFT) calculations from molecular level reveal that the hybridization of Li 1s, S 2p and O 2p orbitals ensures the effective chemisorption between polysulfides and TiO 2 with long-term cycling stability. Consequently, the optimized S@void@TiO 2 electrode maintains a capacity of 766 mAhg−1 after 1000 cycles at 0.2C. Even at 2C for 400 cycles, the capacity still retains at 511 mAhg−1, representing the best results of TiO 2 -based nanostructures for Li-S batteries. This work illustrates that carefully design novel yolk-shell structure is important to address the shortages of sulfur-based cathodes for advanced Li-S battery. [ABSTRACT FROM AUTHOR]

Abstract: New gold catalytic system prepared on ceria-modified mesoporous titania (CeMTi) used as water-gas shift (WGS) reaction catalyst is reported. Mesoporous titania (MTi) was synthesized using surfactant templating method through a neutral [C13(EO)6–Ti(OC3H7)4] assembly pathway. Ceria modifying additive was deposited on MTi by deposition precipitation (DP) method. Gold-based catalysts with different gold content (1–5wt.%) were synthesized by DP of gold hydroxide on mixed metal oxide support. The supports and the catalysts were characterized by powder X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2 adsorption analysis and temperature-programmed reduction (TPR). The catalytic behavior of the gold-based catalysts was evaluated in WGS reaction in a wide temperature range (140–300°C) and at different space velocities and H2O/CO ratios. The influence of gold content and particle size on the catalytic performance was investigated. The WGS activity of the new gold/ceria-modified mesoporous titania catalysts was compared with that of gold catalysts supported on simple oxides CeO2 and mesoporous TiO2, as well as gold/ceria-modified titania and reference catalyst Au/TiO2 type A (World Gold Council). A high degree of synergistic interaction between ceria and mesoporous titania and a positive modification of structural and catalytic properties by ceria has been achieved. It is clearly revealed that the ceria-modified mesoporous titania is of much interest as potential support for gold-based catalyst. The Au/ceria-modified mesoporous titania catalytic system is found to be efficient catalyst for WGSR. [Copyright &y& Elsevier]