The electric‐field effect is an important factor to enhance the charge diffusion and transfer kinetics of interfacial electrode materials. Herein, by designing a heterojunction, the influence of the ...electric‐field effect on the kinetics of the MoS2 as cathode materials for aqueous Zn‐ion batteries (AZIBs) is deeply investigated. The hybrid heterojunction is developed by hydrothermal growth of MoS2 nanosheets on robust titanium‐based transition metal compound (titanium nitride, TiN and titanium oxide, TiO2) nanowires, denoted TNC@MoS2 and TOC@MoS2 NWS, respectively. Benefiting from the heterostructure architecture and electric‐field effect, the TNC@MoS2 electrodes exhibit an impressive rate performance of 200 mAh g−1 at 50 mA g−1 and cycling stability over 3000 cycles. Theoretical studies reveal that the hybrid architecture exhibits a large‐scale electric‐field effect at the interface between TiN and MoS2, enhances the adsorption energy of Zn‐ions, and increases their charge transfer, which leads to accelerated diffusion kinetics. In addition, the electric‐field effect can also be effectively applied to TiO2 and MoS2, confirming that the concept of heterostructures stimulating electric‐field can provide a relevant understanding for the architecture of other cathode materials for AZIBs and beyond.
Herein, heterostructure engineering is employed to generate an electric‐field effect in MoS2 nanosheets via integration with flexible titanium‐based transition metal compound (TiN and TiO2) nanowires. Both theoretical and experimental analyses reveal that the large‐scale electric‐field effect at the interfaces enhances the adsorption energy of Zn‐ions and increases their charge transfer, which leads to excellent performance.
Phase isomerism is a common and important phenomenon in inorganic materials, but the molecular isomerism of their nanocluster models is still rare. In this work, we report the first pair of isomeric ...titanium‐oxo clusters. Through combining pentagonal {Ti(Ti5)} building units in corner‐sharing or edge‐sharing forms, the two obtained Ti20‐oxo clusters take vertical and horizontal core configurations, respectively, which are both functionalized by the same organic ligands. More interestingly, the vertical type Ti20‐oxo core contains an identical {Ti8O14} moiety as anatase, making it the first molecular model of anatase TiO2. As a result, the vertical type cluster exhibits better photocatalytic H2 evolution activity, higher photocurrent response and faster charge transfer to external acceptors than its horizontal isomer. Thus, this work provides a cluster isomer method to understand the structure–property relationship of import titanium oxide materials.
Two isomeric Ti20‐oxo clusters with vertical and horizontal core configurations are reported, which show structure‐dependent photoactivities. The vertical type Ti20‐oxo cluster (left in the picture) is the first molecular model of anatase TiO2 (right), exhibiting better photocatalytic H2 evolution activity, higher photocurrent response and faster charge transfer to external acceptors than its horizontal isomer.
Photocatalytic CO2 reduction reaction (CO2RR) is an attractive process to convert CO2 into valuable chemicals. But this reaction is often restricted by the poor mass transfer of CO2 in the liquid ...phase. Here, we have developed a triphase photocatalytic CO2RR system by supporting Ag‐decorated TiO2 nanoparticles at a gas–water boundary with hydrophobic–hydrophilic abrupt interfacial wettability. Such a triphase system allows the rapid delivery of gas‐phase CO2 to the surface of photocatalysts while maintaining an efficient water supply and uncovered active sites. Ag‐TiO2 supported at the gas–water boundary showed a CO2 reduction rate of 305.7 μmol g−1 h−1, without hole scavengers, approximately 8 times higher than the nanoparticles dispersed in the liquid phase. Even using diluted CO2 (10 %) as the reactant, the CO2RR activity was superior to most reported Ag‐TiO2 based photocatalysts using pure CO2. The findings provide a general strategy to promote the interfacial CO2 mass transfer to improve photoactivity and selectivity.
A triphase photocatalytic CO2 reduction system was developed by supporting Ag‐TiO2 nanoparticles at a gas–water boundary. The as‐formed triphase interface with a hydrophobic–hydrophilic abrupt interfacial wettability ensures the fast supply of CO2, contributing to an enhanced CO2 reduction rate and selectivity. The system also shows feasibility in CO2‐diluted conditions, typically hindered by the poor CO2 mass transfer in conventional systems.
Owing to rapid development in their efficiency
and stability
, perovskite solar cells are at the forefront of emerging photovoltaic technologies. State-of-the-art cells exhibit voltage losses
...approaching the theoretical minimum and near-unity internal quantum efficiency
, but conversion efficiencies are limited by the fill factor (<83%, below the Shockley-Queisser limit of approximately 90%). This limitation results from non-ideal charge transport between the perovskite absorber and the cell's electrodes
. Reducing the electrical series resistance of charge transport layers is therefore crucial for improving efficiency. Here we introduce a reverse-doping process to fabricate nitrogen-doped titanium oxide electron transport layers with outstanding charge transport performance. By incorporating this charge transport material into perovskite solar cells, we demonstrate 1-cm
cells with fill factors of >86%, and an average fill factor of 85.3%. We also report a certified steady-state efficiency of 22.6% for a 1-cm
cell (23.33% ± 0.58% from a reverse current-voltage scan).
The phosphorus-functionalized cycloheptatrienylcyclopentadienyl (ChtCp) titanium sandwich complex (η7-C7H7)Ti(η5-C5H4PtBu2) (7) forms a frustrated Lewis pair (FLP) in combination with the borane ...B(C6F5)3, and this FLP undergoes heterolytic cleavage of dihydrogen and fixation of carbon dioxide and nitrous oxide with a noticeable colorimetric response, which is visible to the naked eye. In their UV/Vis spectra, the H2, CO2 and N2O fixation products exhibit a bathochromic shift of the absorption band that can be assigned to a HOMOLUMO excitation of the ChtCp titanium (troticene) moiety.
Antibiotic-resistant bacteria are frequently involved in implant-associated infections (IAIs), making the treatment of these infections even more challenging. Therefore, multifunctional implant ...surfaces that simultaneously possess antibacterial activity and induce osseointegration are highly desired in order to prevent IAIs. The incorporation of multiple inorganic antibacterial agents onto the implant surface may aid in generating synergistic antibacterial behavior against a wide microbial spectrum while reducing the occurrence of bacterial resistance. In this study, porous titanium implants synthesized by selective laser melting (SLM) were biofunctionalized with plasma electrolytic oxidation (PEO) using electrolytes based on Ca/P species as well as silver and zinc nanoparticles in ratios from 0 to 100% that were tightly embedded into the growing titanium oxide layer. After the surface bio-functionalization process, silver and zinc ions were released from the implant surfaces for at least 28 days resulting in antibacterial leaching activity against methicillin-resistant Staphylococcus aureus (MRSA). Furthermore, the biofunctionalized implants generated reactive oxygen species, thereby contributing to antibacterial contact-killing. While implant surfaces containing up to 75% silver and 25% zinc nanoparticles fully eradicated both adherent and planktonic bacteria in vitro as well as in an ex vivo experiment performed using murine femora, solely zinc-bearing surfaces did not. The minimum inhibitory and bactericidal concentrations determined for different combinations of both types of ions confirmed the presence of a strong synergistic antibacterial behavior, which could be exploited to reduce the amount of required silver ions by two orders of magnitude (i.e., 120 folds). At the same time, the zinc bearing surfaces enhanced the metabolic activity of pre-osteoblasts after 3, 7, and 11 days. Altogether, implant biofunctionalization by PEO with silver and zinc nanoparticles is a fruitful strategy for the synthesis of multifunctional surfaces on orthopedic implants and the prevention of IAIs caused by antibiotic-resistant bacteria.
Implant-associated infections are becoming increasingly challenging to treat due to growing antibiotic resistance against antibiotics. Here, we propose an alternative approach where silver and zinc nanoparticles are simultaneously used for the biofunctionalization of rationally designed additively manufactured porous titanium. This combination of porous design and tailored surface treatment allows us to reduce the amount of required silver nanoparticles by two orders of magnitude, fully eradicate antibiotic-resistant bacteria, and enhance the osteogenic behavior of pre-osteoblasts. We demonstrate that the resulting implants display antibacterial activity in vitro and ex vivo against methicillin-resistant Staphylococcus aureus.
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Formation of crystals with habit planes {443}.sub.a in titanium with BCC-HCP (alpha - epsilon) reorganization is considered within the limits of the dynamic theory of martensitic transformations. It ...is shown that the start of fast wave crystal growth is possible in elastic fields of rectangular dislocation loops with basic segments along the <1bar.10>.sub.alpha directions and the .sub.alpha Burgers vectors. The relative change of the volume delta is considered negative. For wide loops, the habit planes {443}.sub.alpha (like {334}.sub.a) can be associated with invariant planes. For narrow loops, selection in favor of the crystals having habit planes {443}.sub.a is due to the fulfillment of the condition delta < 0. Keywords: dynamic theory, martensite, titanium, habit planes {443}.sub.a.
Peri-implant infection is one of the biggest threats to the success of dental implant. Existing coatings on titanium surfaces exhibit rapid decrease in antibacterial efficacy, which is difficult to ...promisingly prevent peri-implant infection. Herein, we report an N-halamine polymeric coating on titanium surface that simultaneously has long-lasting renewable antibacterial efficacy with good stability and biocompatibility. Our coating is powerfully biocidal against both main pathogenic bacteria of peri-implant infection and complex bacteria from peri-implantitis patients. More importantly, its antibacterial efficacy can persist for a long term (e.g., 12~16 weeks) in vitro, in animal model, and even in human oral cavity, which generally covers the whole formation process of osseointegrated interface. Furthermore, after consumption, it can regain its antibacterial ability by facile rechlorination, highlighting a valuable concept of renewable antibacterial coating in dental implant. These findings indicate an appealing application prospect for prevention and treatment of peri-implant infection.
Poor chemical stability of graphene in titanium (Ti) is one critical problem to make use of the extraordinary properties of graphene for obtaining high-performance graphene/Ti composites. To overcome ...this problem, the selective laser melting (SLM) process with rapid heating and cooling characteristics was exploited to fabricate graphene nanosheet (GNS)-reinforced Ti–6Al–4V matrix composite in this study. Results showed that the SLMed composite registered super-high tensile strength (1526 MPa) and high Young’s modulus (145 GPa), which were 73% and 26% lager than those of spark plasma sintered composites fabricated from the same powder mixture, respectively. It was found that the locally reacted GNSs and in-situ formed ultrafine TiC particles mainly contributed to the outstanding mechanical properties of SLMed GNSs/Ti composites. The underlying mechanism was thoroughly discussed based on microstructures and strengthening models. The results pave up the way towards the fabrication of super-strong Ti matrix composites.
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•GNSs/Ti composites were fabricated by combination of facile mixing and SLM.•Nano-reinforcements and laser scanning strategy impacted on orientation of α-Ti laths.•Ti–TiC-GNSs interface in SLM GNSs/Ti composites were examined by HRTEM.•SLM GNSs/Ti composite possessed super high strength and high modulus.•Load transfer and CET were major strengthening mechanisms of SLM GNSs/Ti composites.
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