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Red phosphorus (RP) is an emerging visible‐light‐responsive photocatalyst, yet the rapid charge recombination has limited photocatalytic hydrogen production activity. In this work, a Z‐scheme heterostructure with RP nanolayer coated on high‐index (116) faceted anatase TiO2 nanoparticles (TiO2@RP) is designed and fabricated via chemical vapor deposition. Compared with pristine TiO2 and RP, the optimized TiO2@RP Z‐scheme heterostructure exhibits a significantly boosted photocatalytic activity for pure water splitting, with hydrogen evolution rate reaching 12.9 µmol·h−1, under simulated solar light irradiation. The strong interfacial interaction and staggered band alignment between (116) faceted TiO2 and RP result in the formation of built‐in electric field, which can drive the directional charge migration from the conduction band (CB) of TiO2 to the valance band (VB) of RP under light irradiation, with photoelectrons and holes of high redox ability maintained at the CB of RP and the VB of TiO2, respectively. This well‐designed heterostructure greatly promotes photogenerated charge separation and migration via a direct Z‐scheme charge transfer pathway. [ABSTRACT FROM AUTHOR]

Summary: The controllable production of TiO2‐based nanostructured composites has attracted great interest for the potential applications in storage energy, catalysis, and photonics. In this work, we demonstrate a facile method to produce amorphous TiO2 nanotube (a‐TNT) arrays with Au nanocrystals (Au NCs) anchoring on the outmost surfaces of the a‐TNTs (Au@TNT arrays) at room temperature. The spatial distribution of Au NCs along the longitudinal direction of the a‐TNT arrays is tunable via the control of the sputtering time of Au. The Li‐ion half cells (LIHCs) with the working electrode made from the Au@TNT arrays possess higher specific capacities than those with pure a‐TNT arrays and exhibit great rate performance. The LIHCs with the Au@TNT arrays prepared with 60 seconds of the Au sputtering time exhibit the best rate performance and deliver discharge capacities of 320, 291, 286, 135, and 122 mAh·g−1 at current densities of 0.1, 0.5, 1, 5, and 10 A·g−1, respectively. The apparent diffusivity of lithium in the LIHCs increases linearly with the increase of the average size of Au NCs (amount of Au NCs/sputtering time). The results obtained in this work suggest that a‐TNTs anchored with metallic nanocrystals have the potential to be anode materials of next‐generation lithium‐ion battery. [ABSTRACT FROM AUTHOR]

Au/TiO 2 nanofilms are prepared on indium-tin oxide glass using magnetron sputtering. The bilayer nanofilms are heat-treated at 500 °C in air for 2 h. The microstructure evolution of the prepared Au/TiO 2 nanofilms is characterized, using scanning electron microscope, energy dispersive spectrometer, and X-ray diffraction. The heat treatment leads to the migration of Au atoms to form Au/TiO 2 nanofilms with TiO 2 being in anatase phase and the presence of Au films/islands on the surface of the Au/TiO 2 nanofilms. The photocatalytic activity of the prepared Au/TiO 2 nanofilms in an aqueous solution of methylene blue (MB) is evaluated under the irradiation of visible light. The experimental results show that the photocatalytic activity of the prepared Au/TiO 2 nanofilms depends on the loading amount of Au. The rate constant for the photodegradation of the MB compound in the aqueous solutions with pure TiO 2 nanofilms is less than those with the prepared Au/TiO 2 nanofilms. Such behavior can be likely attributed to the activation of the photo-generated charge carriers and the increase of the electron–hole separation efficiency through localized surface plasmon resonance. [ABSTRACT FROM AUTHOR]

This study focused on the microwave-assisted one-step synthesis and evaluation of visible light-sensitized Ce, N, and P tri-doped titanium dioxide nanoparticles loaded on activated carbon (TiO 2 /AC) photocatalyst for the photocatalytic degradation of naphthalene. X-ray photoelectron spectroscopy (XPS) of the samples showed the presence of both Ce 3+ and Ce 4+ oxidation states. A red shift of the absorption edge in the UV–visible spectra was observed when Ce, N, or P was doped in the band gap of TiO 2 . Ce, N, and P tri-doped TiO 2 /AC exhibited the highest photocatalytic activity (97.9%) and rate constant under visible-light irradiation. The photocatalyst could be applied in environmental purification as indicated by its excellent performance. The possible synergetic mechanism for the photodegradation was also discussed. This study provides an effective strategy for synthesizing novel high-performance TiO 2 nanocomposite photocatalyst to degrade naphthalene. [ABSTRACT FROM AUTHOR]

Abstract: Novel Cu2O/Pt/TiO2 three-layered nanocomposite films were prepared by deposition on glass substrates using the magnetron sputtering method. Their structure, surface morphology as well as optical and photocatalytic properties were examined by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, UV–visible spectroscopy, and photoluminescence spectroscopy. As a comparison, Cu2O/TiO2 double-layer films were also investigated. The results show that Cu2O/TiO2 double-layer films have relatively smooth surfaces with agglomerated Cu2O particle, whereas the surface layer of the Cu2O/Pt/TiO2 three-layered nanocomposite films was composed of fine nano-sized columnar Cu2O and they had a rough surface morphology due to the insertion of the Pt layer. The photocatalytic activity of the three-layered films is significantly higher than that of the Cu2O/TiO2 double-layered composite films. Such enhancement is closely related to the presence of the Pt layer and the rough surface, which was composed of fine nano-sized Cu2O columns; this increases the utilization of visible light as well as promotes the transfer of interfacial charge and the separation of photogenerated electron–holes. [Copyright &y& Elsevier]

Abstract: Cu, N and CuN-doped anatase TiO2 are studied using density functional theory (DFT). It is found the band gap decreases after CuN co-doped. The intensity of adsorption spectra increases in the following order: CuN codoped⪢Cu-doped⪢N-doped⪢pure anatase in visible region, indicating that the electrons on the valence band easily transit to the conduction band. In other words, theoretic calculation shows that the photocatalytic activity of CuN co-doped is higher than that of the corresponding single Cu or N-doped. [Copyright &y& Elsevier]

[Display omitted] • PEC performance of NiO uniformly loaded B-doped TiO2 nanotube arrays generated via CV electrodeposition and in situ B-doping was excellent (2.14 mA/cm2). • With an IPCE of 82.5%, dual manipulation of the energy band structure by B doping and NiO substantially decreases the prohibited bandwidth of TNAs. • NiO improves charge injection efficiency, while B doping improves charge separation efficiency; the synergistic impact of the two provides a rapid and efficient PEC process. The severe photogenerated charge recombination rate, poor visible light utilization and slow oxygen precipitation kinetics are the technical bottlenecks limiting the photo-electrolysis of TiO 2 nanotube array (TNAs) photoanode for hydrogen production from water. To solve these problems, NiO nanoparticles were uniformly loaded into B-doped TNAs by the CV method. It is found that B-doping improves the energy band structure of TNAs, and doping-induced surface defects could become traps for photogenerated carriers to substantially improve the charge separation efficiency of the bulk phase. The P-N junctions formed between TiO 2 anatase and NiO nanoparticles not only promoted the OER kinetics at the interface but also greatly improved the surface carrier separation efficiency of the catalyst, as well as ensured the stability and activity of the B-doping-induced surface defects. Moreover, the carrier concentration and visible light absorption properties of TNAs were enhanced and improved. Due to the synergistic effect of B doping and NiO loading, the bulk charge separation efficiency and surface charge separation efficiency of NiO/BT (B doping and NiO loading TNAs) were as high as 88.9 and 82.4%, respectively, at 1.23 V vs. RHE, and the photocurrent density reached 2.05 mA/cm2, which was 10 times higher than that of pure TNAs. [ABSTRACT FROM AUTHOR]

Dual co-catalysts have an essential effect on improving the photoelectrochemical (PEC) performance of semiconductor materials. In this study, Ni–Ni(OH) 2 or/and Nikel phosphate (NiPi) nanocrystals co-catalysts were deposited on the surface of as-prepared TiO 2 nanotube arrays (TNTAs) by a simple electrodeposition route for PEC hydrogen production. The TNTAs loading with Ni and NiPi bifunctional co-catalysts exhibited remarkably enhanced PEC performance, with about an 8.3-fold increase in the photocurrent; and an 11.7-fold improvement in H 2 evolution rate in comparison to bare TNTAs. The constructed ternary TNTAs/Ni–Ni(OH) 2 /NiPi comprised the advantage of Ni–Ni(OH) 2 and NiPi nanoparticles to enhance visible-light absorption and promote oxygen evolution reaction (OER) kinetics. The internal electric field is generated between supported p-type Ni(OH) 2 and n-type TiO 2 under light irradiation, which will drive holes to flow to Ni(OH) 2 and oxidize it as the OER active layer. Also, the photo-generated holes remaining in the TiO 2 valence band can migrate to NiPi co-catalysts to cause OER. Therefore, the photogenerated electron-hole pairs can be successfully separated under the synergetic influence of Ni–Ni(OH) 2 and NiPi co-catalyst, leading to a superior PEC water splitting ability. • Dual Ni-based co-catalysts were electrodeposited on TiO 2 nanotube arrays (TNTAs). • Ternary TNTAs/Ni–Ni(OH) 2 /NiPi exhibited higher photocurrent than bare TNTAs. • Both Ni–Ni(OH) 2 and NiPi enhance light absorption and promote the OER of TNTAs. • Ni–Ni(OH) 2 and NiPi have a synergetic effect to improve carrier's separation ability. [ABSTRACT FROM AUTHOR]

[Display omitted] • TiO 2 NRs/BiOCl//TiO 2 NRs/BiOCl UV PD produces pyro-phototronic effect by a face-to-face assembly method. • BiOCl increases the surface oxygen vacancies of TiO 2 NRs, reducing the dark current of UV PD. • The Cl ions combined with Se increase the photosensitivity of the material, thus increasing UV PD performance. This study presents the construction of an organic–inorganic heterojunction ultraviolet (UV) photodetector (PD) through face-to-face assembly. The synergistic effects of bismuth oxychloride (BiOCl) and titanium dioxide nanorods (TiO 2 NRs) improve carrier transport efficiency and enhance the performance of the UV photodetector. The combination of BiOCl with TiO 2 NRs generates a pyro-phototronic effect and increases the surface oxygen vacancies of TiO 2 NRs, resulting in enhanced carrier transport efficiency, increased transient photocurrent, and reduced dark current in TiO 2 -based UV photodetectors. The enhanced photosensitivity of chloride (Cl) ions bound to selenium (Se) ions promotes easy electron injection from poly (3,4-ethylene dioxyselenophene) (PEDOS) into BiOCl, leading to accelerated electron transfer and a shortened response time. Compared to TiO 2 NRs/BiOCl//TiO 2 NRs/BiOCl, the TiO 2 NRs/BiOCl//PEDOS heterojunction exhibits a fast photoresponse with a rise time of 0.0802 s and a fall time of 79.8 ms. The responsivity is significantly improved from 11.0 mA/W to 108.8 mA/W (a 10-fold enhancement), and the detectivity is increased from 0.67 × 1011 Jones to 1.25 × 1011 Jones at 365 nanomaterials (0 V). These findings provide valuable insights into the mechanism by which BiOCl nanosheets enhance the photodetection performance of devices, contributing to the advancement of UV photodetector technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • A WO 3 /TiO 2 photoelectrode was prepared, showcasing the synergistic interplay between the two materials. • Different levels of WO 3 loading have distinct impacts on the photoelectrochemical properties and glycerol oxidation performance of the composite material. • The formation of a Z-scheme heterojunction between TiO 2 and WO 3 significantly improved surface charge separation efficiency. • The high-selective conversion of glycerol is accomplished through the synergistic interaction between TiO 2 and WO 3. Developing highly efficient photocatalysts for the selective conversion of glycerol into valuable chemicals is of paramount importance. However, achieving the selective oxidation of glycerol to valuable C 3 chemicals poses significant challenges. In this study, we employed a two-step hydrothermal method to synthesize a photoelectrochemical (PEC) photocatalyst composed of WO 3 nanosheets assembled on TiO 2 nanorod arrays. The synergistic interaction between WO 3 and TiO 2 led to outstanding performance in the selective conversion of glycerol (GLY) into glyceraldehyde (GLD) and 1,3-dihydroxyacetone (DHA). The photocatalyst achieved a selectivity of 61% for GLD and 92% for GLD + DHA, with formation rates of 319 and 160 mmol m-2h−1, respectively. Despite the excellent charge transfer properties of TiO 2 nanorods, they displayed suboptimal glycerol conversion rates and tended to oxidize glycerol into lower-value products. The introduction of WO 3 nanosheets in the Z-scheme heterojunction improved charge separation, enhanced glycerol adsorption and facilitated the desorption of GLD and DHA, thus improving the selectivity of GLD + DHA. This study unveils a promising approach to efficiently oxidize glycerol and demonstrates the crucial role of catalyst design in achieving selective and high-yield chemical transformations. [ABSTRACT FROM AUTHOR]

Abstract: Poly (lactic acid)/anatase-titanium dioxide (PLA/A-TiO2) and PLA/rutile-TiO2 (PLA/R-TiO2) composites were prepared by spin coating technique (thin film) and extrusion-injection processing (thick film), respectively. The ultraviolet (UV) photoresponse effects of the two oxide structures were investigated mainly by measuring the UV absorbance or mechanical properties. For the thin films, the UV absorbance results exhibit a UV shielding effect of R-TiO2 and a degradation acceleration effect of A-TiO2 when the particles are embedded in PLA matrix. But for the thick films, the mechanical property results only exhibit a UV shielding effect of both R-TiO2 and A-TiO2 particles and improve the anti-UV performance of PLA when the particles are encapsulated in PLA matrix. [Copyright &y& Elsevier]

[Display omitted] • The UV PD was constructed face-to-face from TiO 2 NRs: CQDs/FTO and PEDOS/FTO. • Sensitization of TiO 2 NRs by CQDs enhances the pyro-phototronic effect of TiO 2 NRs. • CQDs and PEDOS interact with each other and have matching energy levels. • The photovoltaic-pyroelectric coupled effect enhanced the performance. • The UV PD have high responsivity and detectivity in the self-powered model. TiO 2 -based ultraviolet (UV) photodetectors (PDs) with broadband optical detection range are widely used in commercial and military applications. Nevertheless, the self-powered UV PDs of TiO 2 nanoarrays (NRs) have relatively low response rates and slow response times. Here, a high responsivity self-powered p-n heterojunction UV PD based on TiO 2 NRs: CQDs/FTO and PEDOS/FTO is fabricated by a simple face-to-face assembly process. The pyroelectric effect of TiO 2 NRs is enhanced by sensitizing TiO 2 NRs with CQDs, which would reduce the bandgap value of TiO 2 NR, broaden the range of photoresponse, and reduce recombination of electron-hole. Furthermore, the pyro-phototronic effect of CQDs, the energy level matching from CQDs to PEDOS and the interaction between –OH in CQDs and ethylene oxide groups in PEDOS enhance the performance of the prepared UV PDs. The TiO 2 NRs: CQDs//PEDOS UV PDs achieve a high photo-responsivity and photo-detectivity of 150.95 mA/W and 3.73 × 1011 Jones at 0 bias (365 nm), respectively, which are better than those at wavelengths of 380 nm. We also found that the photocurrent induced via the pyro-phototronic effect increases with the light power intensity. This work points the way for photovoltaic and photo-induced pyro-phototronic effects to improve the performance of TiO 2 NRs-based UV PDs. [ABSTRACT FROM AUTHOR]

Solar-driven water splitting to produce hydrogen is an important solution to the problem of energy shortage and environmental pollution. The photolysis of water to produce hydrogen requires highly efficient and stable photocatalysts, and the anode used as catalyst for oxygen evolution is a bottleneck in this process. In this paper, the a-TNTAs/Ni 2 P composite photo-anode was constructed by electrodeposition to anchor the Ni 2 P co-catalyst for oxygen evolution at the active site of TiO 2 nanotube arrays (TNTAs). The a-TNTAs/Ni 2 P delivered excellent oxygen evolution at a photocurrent density of 1.058 mA cm-2, an improvement of 2.78 times, 13.2 times, and 15.8 times over a-TNTAs, TNTAs/Ni 2 P, and TNTAs photo-anodes, respectively. The Mott-Schottky curve showed that Ni 2 P as co-catalyst for oxygen evolution accelerated the rates of separation and transfer of the photogenerated electrons. This research provides a simple and efficient method to promote the OER performance of optical semiconductors. • a-TNTAs/Ni 2 P is synthesized by a simple and convenient electrodeposition. • Ni 2 P cocatalyst reduce the water oxidation overpotential of anatase TiO 2. • a-TNTAs/Ni 2 P photocatalyst has good photocurrent stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • In situ B doping successfully modified the defect concentration and lattice stress of the titanium oxide nanotube arrays. • The energy band structure of titanium oxide nanotube arrays was improved by B doping, while the reactivity of PEC was heightened by the induced surface defects. • The lattice stress induced by B doping enhances carrier separation efficiency, mitigates bulk defects' negative impact on carrier transport, and ensures catalyst stability. The role of the boron (B) doping induced defect state in the PEC process is still unclear though B doped TiO 2 nanotube arrays (TNAs) via anodic oxidation has commonly used to improve the photocatalytic decomposition of water by TNAs. Therefore, this work aims to establish the underlying reasons for the high PEC reactivity and stability maintained by the B doping induced defective states. Special attention is paid to the differences in carrier behavior and surface reactivity in the PEC process between the B doped induced and NaBH 4 treatment induced defective states. DFT calculations show that B doping can effectively reduce the generation energy of Ti3+/V o (oxygen vacancies) pairs and enhance the adsorption energy of defects on the surface of TiO 2 (1 0 1) for H 2 O and ·OH. Moreover, due to the presence of B atoms, the surface defects of TiO 2 can maintain high adsorption of H 2 O and ·OH, without being deactivated by the healing of oxygen vacancies, which ensures the stability and activity of the catalyst. Meanwhile, the lattice stress induced by B doping forms the internal electric field, which ensures the efficient separation of carriers in the bulk phase and avoids the negative effect of bulk phase defects on carrier separation. [ABSTRACT FROM AUTHOR]

We study anodic growth of TiO 2 nanotubes on the surfaces of Ti rings of different thicknesses in a two-electrode cell under 50 V with an anodization time of 30 min at room temperature. The experimental results demonstrate that there are three factors controlling the growth of TiO 2 nanotubes on the surfaces of Ti rings – ring radius, ring thickness and residual stress. The length of TiO 2 nanotubes decreases with the increase of the radius of Ti rings and the decrease of the ring thickness. The residual stress hinders the growth of TiO 2 nanotubes on the surfaces of Ti rings. Effects of radius of curvature and residual stress on anodic growth of TiO 2 nanotube arrays. [Display omitted] • TNT length is dependent on radius and thickness of Ti tube. • TNT length is dependent on local curvature. • Residual stress hinders the growth of TNTs on Ti tube. [ABSTRACT FROM AUTHOR]

Understanding structural integrity of physical structures in chemical and electrochemical systems/environments is of practical importance in analyzing and predicting the reliability and lifespan of the physical structures. In this work, we systematically investigate the crack growth in the TiO 2 layers with TiO 2 nanotube arrays during electrochemical anodization of Ti plates without external mechanical loading. There exists the combinational effects of the anodization voltage and the anodization temperature on the crack growth. A simple relationship between the growth rate of the areal crack density, the anodization temperature and the anodization voltage are proposed and supported by the experimental results. The growth rate of the areal density of the surface cracks increases with the increase of the anodization voltage and the anodization temperature. The nominal activation energy is a decreasing function of the anodization voltage, suggesting that increasing the anodization voltage promotes fast growth of the surface cracks in the TiO 2 oxide layer. [Display omitted] • There exists the combinational effects of the anodization voltage and the anodization temperature on the crack growth. • The growth rate of the areal density of the surface cracks increases with the increase of the anodization voltage and the anodization temperature. • The nominal activation energy is a decreasing function of the anodization voltage, suggesting that increasing the anodization voltage promotes fast growth of the surface cracks in the TiO 2 oxide layer. [ABSTRACT FROM AUTHOR]

Developing efficient and sustainable photocatalyst is crucial for antibiotic degradation in water treatment. Iron (Fe) species modified semiconductor photocatalysts have been widely used in visible-light driven Fenton-like systems. However, the limited dispersion of Fe sites and low redox rate of the Fe(III)/Fe(II) restrict the catalytic performance. Herein, the atomic Fe sites with highly dispersed coordination centers were confined (100) facets exposed titania nanofibers (Fe-TNFs) for efficient photocatalytic Fenton-like norfloxacin (NOR) degradation. The optimized Fe-TNFs catalyst could achieve 95% NOR removal after 5 h of white LED illumination, which is 15% higher than that of nanostructured Fe species. The high performance is credited for the enhanced visible light absorption, and the efficient electron transfer through Fe–O bonds in Fe-TNFs enables the fast cyclic transformation of Fe(III)/Fe(II), which can promote the continuous production of •OH in the photocatalytic Fenton-like system. This study can provide technical support for the developing a feasible and sustainable wastewater treatment solution, and provide reference for the fate and risk assessment of antibiotics in the environment. • Atomic Fe was confined on (100) exposed TiO 2 by molten salt method. • Single atomic Fe sites improve visible light absorption. • Atomic Fe enhances the cyclic transformation of Fe(III)/Fe(II). • Fe sites accelerate the formation of •OH for efficient norfloxacin degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Boric acid effectively improves the bonding force between Ti substrate and TNAs. • A detailed study of the relationship between the interfacial behavior and the binding force of TNAs. • The addition of boric acid can effectively reduce the content of fluoride ions in TNAs, thereby improving its binding force to the base. TiO 2 nanotube arrays prepared in a hydrofluoric electrolytes are prone to peeling off from the underlying titanium due to a weaker interfacial adhesion between the nanotube layers and Ti substrates. Herein, a new method is proposed to adjust the growth process of nanotubes by adding boric acid to the anodizing electrolytes to increase the adhesion. Results revealed that boric acid form complex with F- at high concentration and slowly releases F- as the reaction proceeds, thereby slowing down the growth rate of the nanotubes and inhibiting the fluoride-rich TiO 2 layer that causes the poor adhesion. The improved binding force is attributed to the combined effect of the "fluoride ion enrichment" theory and the "residual stress" theory. Furthermore, the addition of boric acid increases the photoelectric catalytic performance of titanium dioxide nanotube arrays by about 7 times, and the capacitance area increased by 55.10%. [ABSTRACT FROM AUTHOR]

• A cold rolling effectively improves the adhesion between Ti substrate and TNAs. • The influence mechanism of the microstructure of the Ti matrix on the growth process of TNAs and the adhesion between TNAs and the matrix was studied in detail. • The improved finer grain sizes and increased dislocation density may reduce the F contents and release the stress at the interface of TNAs and Ti, thereby improving its adhesion to the base. TiO 2 nanotube arrays (TNAs) prepared by the traditional methods are prone to peeling off from the underlying titanium due to the weak interfacial adhesion between the nanotube layers and Ti substrates, which greatly restricts their applications. Here, 2.5 mm titanium plates are cold rolled to the Ti sheets of various thicknesses by controlling the cold-rolling reduction process. Ti sheets are then anodized in an electrolyte that was composed of water, NH 4 F, and ethylene glycol. It is discovered that after the cold-rolling process, not only are the pore sizes of the nanotubes smaller, but also the tube length is longer, indicating different growth behavior for the rolled Ti sheets. The results of XRD, EBSD, and metallographic microstructure analysis revealed mechanical anchorage at grain boundaries and decreased F contents, which leads to release stress at the TNAs/Ti interface. Most probably the released stress, finer grain sizes and increased dislocation density are responsible for the improved adhesion. [ABSTRACT FROM AUTHOR]