SrTiO3 Particles Research Articles

Salt-induced anisotropic SrTiO3 to boost piezo-photocatalytic processes

Piezo-photocatalysis materials that can combine the piezoelectric effect in photocatalytic processes are very attractive for promising applications in water splitting and contaminant degradation. The perovskite oxides with adjustable exposed crystal facets are expected to optimize the catalysis activities by exposing the high-energy planes. In this work, we develop a salt-assisted strategy that controllably prepares anisotropic SrTiO3 particles with a large number of surface defects, which exhibit good piezo-photocatalytic features. The exposure of the crystal facets can be tuned by changing the assistants (NaCl or SrCl2). The SrCl2 can lead to the exposure of the (110) plane in one-dimensional SrTiO3 particles and NaCl can induce the cubic SrTiO3 particles with the exposure plane of (200). Attributed to the exposed high-energy facets and abundant oxygen vacancies, the latter show higher activities than the former in both water splitting and dye degradation under light irradiation and ultrasonic vibration. Our work provides an approach to optimize piezo-photocatalytic activities by tuning the exposed crystal facets.

Effective photocatalytic degradation of sulfamethoxazole using PAN/SrTiO3 nanofibers

Freshwater scarcity driven by pollution and climate change necessitates the development of effective water purification methods. There is an urgent need for innovative solutions that can efficiently remove contaminants from water sources. A effective material for the photocatalytic degradation of organic sulfonamide antibiotics from water was developed in this study. A composite of electrospun strontium titanate (SrTiO3) and carbon fibers polyacrylonitrile/strontium titanate (PAN/SrTiO3) was employed for the photocatalytic degradation of sulfamethoxazole (SMX). Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM-EDS), Transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterise the composite. The fibers had a thickness of ~250 nm and uniformly dispersed PAN and SrTiO3 particles. A PAN/SrTiO3 composite with a 1:1 mass ratio (20 mg) demonstrated excellent performance, achieving over 90 % degradation at pH 7 and a contaminant concentration of 5 mg/L under ultraviolet (UV) light irradiation during 60 min. The composite was tested for the photodegradation of the major organic pollutant (SMX) in distilled and river water. In river water, the degradation efficiency exceeded 80 % at pH 7 because of the formation of secondary radicals involved in antibiotic degradation. SMX degradation was described using a pseudo-first order kinetic equation using the Langmuir-Hinshelwood model. These results underscore the novelty and significance of the PAN/SrTiO3 composite and demonstrate its high efficiency and potential for large-scale water purification applications.

Synthesis Of Nano-Porous Strontium Titanate Materials for Photocatalysis

Strontium titanate semiconductor materials have been widely used in the field of photocatalysis due to their high dielectric constant and band gap. Uniform, micron-sized SrTiO3 particles didn’t tend to aggregate, and the low surface area of larger particles could be improved by incorporating porous structures, thus offering superior performance for a range of applications. In this study, six mainly methods to prepare nano-porous SrTiO3 particles were showed and discussed. The methods include hydrothermal method，sol gel method, chemical co-precipitation method, high temperature solid phase method, hard template method and soft template method. These processes and their advantages and disadvantages were analysised.

Modeling Particle-Doped Materials for Performance Improvement of Contact-Separation Triboelectric Nanogenerators

Triboelectric nanogenerators (TENGs) are an attractive energy harvesting technology due to their high efficiency and vast applications in self-powered sensors. In this work, dielectric–dielectric contact-separation TENGs were modeled with time-dependent finite element simulations with the objective of improving TENG’s performance by enhancing the relative permittivity (εr).To achieve this, the chosen material (PDMS, εr=2.75) was doped with SrTiO3 (εr = 300) particles. The open-circuit voltage (VOC) and short-circuit current (ISC) remained constant as ϵr increased, as predicted by existent models, but in contradiction with available experimental data. Thus, we introduced a charge correction model relating ϵr and surface charge density, allowing us to observe an increase in TENG performance output (VOC and ISC). This work shows that finite element simulations are suitable for better understanding and optimizing TENGs’ performance.

Synthesis and Study of SrTiO3/TiO2 Hybrid Perovskite Nanotubes by Electrochemical Anodization.

Layers of TiO2 nanotubes formed by the anodization process represent an area of active research in the context of innovative energy conversion and storage systems. Titanium nanotubes (TNTs) have attracted attention because of their unique properties, especially their high surface-to-volume ratio, which makes them a desirable material for various technological applications. The anodization method is widely used to produce TNTs because of its simplicity and relative cheapness; the method enables precise control over the thickness of TiO2 nanotubes. Anodization can also be used to create decorative and colored coatings on titanium nanotubes. In this study, a combined structure including anodic TiO2 nanotubes and SrTiO3 particles was fabricated using chemical synthesis techniques. TiO2 nanotubes were prepared by anodizing them in ethylene glycol containing NH4F and H2O while applying a voltage of 30 volts. An anode nanotube array heat-treated at 450 °C was then placed in an autoclave filled with dilute SrTiO3 solution. Scanning electron microscopy (SEM) analysis showed that the TNTs were characterized by clear and open tube ends, with an average outer diameter of 1.01 μm and an inner diameter of 69 nm, and their length is 133 nm. The results confirm the successful formation of a structure that can be potentially applied in a variety of applications, including hydrogen production by the photocatalytic decomposition of water under sunlight.

Liquid metal-embraced photoactive films for artificial photosynthesis

The practical applications of solar-driven water splitting pivot on significant advances that enable scalable production of robust photoactive films. Here, we propose a proof-of-concept for fabricating robust photoactive films by a particle-implanting technique (PiP) which embeds semiconductor photoabsorbers in the liquid metal. The strong semiconductor/metal interaction enables resulting films efficient collection of photogenerated charges and superior photoactivity. A photoanode of liquid-metal embraced BiVO4 can stably operate over 120 h and retain ~ 70% of activity when scaled from 1 to 64 cm2. Furthermore, a Z-scheme photocatalyst film of liquid-metal embraced BiVO4 and Rh-doped SrTiO3 particles can drive overall water splitting under visible light, delivering an activity 2.9 times higher than that of the control film with gold support and a 110 h stability. These results demonstrate the advantages of the PiP technique in constructing robust and efficient photoactive films for artificial photosynthesis.

Enhancement TiO2 photocatalytic hydrogen production via using ABO3 to construct heterojunction

The lower photogenerated carrier separation efficiency seriously hinders the photocatalytic performance of TiO2. In order to solve this problem, we utilized SrTiO3 particles with low cost, good response to visible light, tunable band structure, and type II heterojunction with TiO2 to improve the photogenerated carrier separation efficiency of TiO2 in this study. The TiO2/SrTiO3 heterojunctions have a larger specific surface area than pristine TiO2, pristine SrTiO3. The results confirmed that the formation of heterostructures reduce the interfacial resistance of charge transfer; the transient and effectively improve the electron-hole pair separation efficiency. The hydrogen production efficiency of TiO2/SrTiO3 heterojunction composite is 807.7 μmolg−1h−1, which is 26 times higher than pure TiO2 nanotubes. This work provides a new way to prepare efficient and low-cost photocatalysts using ABO3.

Synthesis, Structure, and Energetic Characteristics of Perovskite Photocatalyst SrTiO3: an Experimental and DFT Study

SrTiO3-based photocatalysts have become widely used due to their excellent properties such as high thermal stability, photocorrosion resistance, and stable structure that can be modified by doping and making composites. In this work, SrTiO3 powder was prepared from Sr(NO3)2 and TiO2 precursors by a simple chemical precipitation method followed by calcination. It was determined that calcination at 900 °C followed by treatment in nitric acid solution produced cubic SrTiO3 particles without the presence of any impurities. In addition, structural, morphology, and energetic characterization using experimental and theoretical aspects are presented. Within the framework of density functional theory, the electronic properties of SrTiO3 have been investigated in the Quantum ESPRESSO software package using the PBE functional under the generalized gradient approximation (GGA). The band structure and density of states were obtained, and the width of the bandgap was determined.

Low-temperature synthesis of Nb-doped and Mn-doped SrTiO3 with easily controllable particle size

Heterovalently doped perovskite-type oxides are used in various electronic applications. Herein, we propose a low-temperature synthesis method for Nb- and Mn-doped SrTiO3 particles with a wide range of particle sizes that is conducted at temperatures close to room temperature (RT). The cation-doped SrTiO3 particles were synthesized under diverse solution conditions by varying the aging temperature, aging period, viscosity of solvents, and OH− concentration using facile and low-cost methods. The particle sizes were simply controlled by changing the ratio of H2O/ethanol solvents owing to their difference in viscosity at low temperatures. The uniformity of the particle sizes was significantly improved via a two-step aging process, that is, heating at a low temperature followed by RT aging. Additionally, the OH− concentration in aqueous solution had considerable impact on the rate of crystal growth, affecting particle size as well as morphology. This study demonstrates the feasibility for the low-temperature synthesis of cation-doped perovskite-type materials.

(Invited) Tuning Photocatalytic Activity with Energetic and Kinetic Asymmetry at Coating-Stabilized Particulate Semiconductors

Semiconductor photocatalysts coevolve reductive and oxidative reactions at nanoscale proximity. The local charge separation and local coevolution have unique advantages: i) photocatalysts can operate in neutral pH water or water vapor instead of strong acid or base; ii) most semiconductors form a self-passivating layer at corroded surfaces to prevent corrosion propagation; and iii) nanoparticulate photoabsorbers or nanocrystalline films have achieved near-unity quantum efficiency, promising scale-up solar-to-chemical conversion. Despite the near-unity quantum efficiency achieved for SrTiO3 particles, the Edisonian approach is applied to the vast majority of photocatalysts, thus limiting progress. Technologically important semiconductors of 1.1 – 2.3 eV bandgaps and properly adjusted band edges, such as GaP and Si, can be ball milled into powder, followed by chemical passivation and protective coating processes. Thus, we introduce the Hu-lab-invented charge-transport coatings to protect semiconductors, such as silicon and gallium indium phosphide. We tune their photocatalytic activity by varying and measuring the energetics and kinetics at local reactive sites, in the following case studies.First, we combine photoelectrochemical cells with local potential-sensing probe microscopy to elucidate photocatalytic processes. In particular, we focus on local energetics and kinetics of multiple concurrent redox processes, i.e., two-redox chemistry. Figure 1A illustrates such a three-terminal photo-electro-catalytic cell setup, where the photoelectrode materials are photocatalysts by themselves. We showcase the efficient charge-separation design by fabricating photocatalysts with particulate semiconductors (e.g., commercial CdS powders, GaInP2 epitaxial layers, and ball-milled GaP nanoparticles), TiO2 coatings, and Rh cocatalysts for the concurring reduction of water and oxidation of reversible redox mediators or sacrificial reagents.We discovered that nanoscale site energetics are mutually dependent on local charge-transfer kinetics.[1] Besides, all known visible-light active photocatalysts of 1.1 – 2.3 eV bandgap photo-oxidize or corrode in water.[2] We discovered multi-functional protective coatings that i) allow for both electrons and holes to transport at tunable energy levels;[3] ii) shift band edges favorably, [4]; iii) reduce charge trapping and recombination,[5] and iv) tune water-oxidation selectivity between O2 and hydrogen peroxide production. [6] We show that in the presence of quinone redox couples in a bicarbonate solution, CO is produced with a 1-atm CO2-free Ar-purged headspace where the only source of CO2 is the (bi)carbonate anions, whilst the quinone redox couples can systematically vary the band edge positions of GaInP photoabsorbers.As shown in Figure 1B, CO evolution rate for both Fe(CN)6 3-/4- and H2BQ/BQ are higher at pH 7 than pH 8.5. The local CO2 concentration at pH 8.5 limited CO production rates. This observation corroborates our hypothesis that photocatalytic redox reactions locally drive pH swing to release CO2 at the oxidative sites, whereas the nearby reductive sites reduce in-situ generated CO2 into CO2R products. We envision direct solar fuel production from natural resources such as sunlight, bicarbonates from the ocean, or moisture in the air in a durable particle reactor.[7] We also processed wood and leaves into pulps and performed photocatalytic H2 production from the CdS/TiO2/Rh/CoOx panel (Figure 1C) using bottom LED illumination, as the glucose solution became colored.In summary, we show the rational design of photocatalysts. These coating-stabilized semiconductor particles present a scalable pathway for making H2 while effectively activating water and biomass as the two most abundant oxidants. We address the timescale mismatch between light absorption and catalysis by effectively accumulating electrons and holes at the respective reductive and oxidative sites.[8] The study paves the way for utilizing biomass to obtain bioenergy with carbon capture and storage.

Al–SrTiO3/Au/CdS Z-schemes for the efficient photocatalytic H2 production under visible light

Development of sustainable solar fuels to meet the continued increase in the energy need worldwide is of particular importance. In addition, reducing carbon emissions could be the last hope to solve global challenges such as global warming and climate change. For this endeavor, different Al–SrTiO 3/Au/CdS Z-Scheme samples were developed by changing the weight percentage (wt. %) of gold nanoparticles (Au NPs) and the wt% ratio of Al–SrTiO3 to CdS NPs using post annealing of mixed powders method. The prepared samples were characterized using several physicochemical techniques to reveal their properties, then their photocatalytic H2 evolution performance was evaluated under visible light using photodeposited RhCr2O3 as H2 evolution cocatalyst. Our results showed that, Al–SrTiO3 particles possessed high crystallinity and cubic perovskite phase, Au NPs exhibited face-centered cubic (FCC) structure, and CdS NPs had cubic Zinc Blende phase as confirmed by XRD analysis. Our UV–Vis. diffuse reflectance analysis revealed that all prepared Z-scheme samples obtained a strong absorption in both UV and visible regions. SEM analysis confirmed the cubic morphology of the perovskite Al–SrTiO3 particles which were randomly deposited by Au NPs of relatively smaller size. While CdS NPs showed semi-spherical shape and were conjugated with Al–SrTiO3 directly to form the proposed Z-Schemes as proposed by our STEM mapping analysis. The highest amount of H2 (656.7 μ mole) was evolved by Al–SrTiO3/4 wt% Au/CdS (1:1) Z-scheme sample after 3 h of visible light irradiation. This sample had 4 wt % of Au NPs and equimolar ratio of Al–SrTiO3 and CdS NPs. This relatively higher activity might be because of the efficient light absorption, prolonged lifetime of the photogenerated charge carriers and improved charge separation as revealed by the PL analysis. Our study can promote the ongoing efforts toward more carbon neutral societies.

Reduction and Diffusion of Cr-Oxide Layers into P25, BaLa4Ti4O15, and Al:SrTiO3 Particles upon High-Temperature Annealing.

Chromium oxide (Cr2O3) is a beneficial metal oxide used to prevent the backward reaction in photocatalytic water splitting. The present work investigates the stability, oxidation state, and the bulk and surface electronic structure of Cr-oxide photodeposited onto P25, BaLa4Ti4O15, and Al:SrTiO3 particles as a function of the annealing process. The oxidation state of the Cr-oxide layer as deposited is found to be Cr2O3 on the surface of P25 and Al:SrTiO3 particles and Cr(OH)3 on BaLa4Ti4O15. After annealing at 600 °C, for P25 (a mixture of rutile and anatase TiO2), the Cr2O3 layer diffuses into the anatase phase but remains at the surface of the rutile phase. For BaLa4Ti4O15, Cr(OH)3 converts to Cr2O3 upon annealing and diffuses slightly into the particles. However, for Al:SrTiO3, the Cr2O3 remains stable at the surface of the particles. The diffusion here is due to the strong metal-support interaction effect. In addition, some of the Cr2O3 on the P25, BaLa4Ti4O15, and Al:SrTiO3 particles is reduced to metallic Cr after annealing. The effect of Cr2O3 formation and diffusion into the bulk on the surface and bulk band gaps is investigated with electronic spectroscopy, electron diffraction, DRS, and high-resolution imaging. The implications of the stability and diffusion of Cr2O3 for photocatalytic water splitting are discussed.

Ultra-high dielectric constant and thermal conductivity SrTiO3@VTMS/PB composite for microwave substrate application

In this study, vinyltrimethoxysilane (VTMS) treated SrTiO3 particles were composited with polybutadiene (PB) using doctor blade and hot-pressing approaches (xSrTiO3@VTMS/PB, x = 84–90 wt%) to satisfy the application in microwave band. The effects of SrTiO3 doping on the microstructure and dielectric properties were investigated detailly. Thermal and mechanical properties of the composite were also discussed in this paper. When x = 87.5 wt%, SrTiO3@VTMS/PB reached the best dielectric properties of highest dielectric constant (εr ∼ 21.1) with low dielectric loss (tanδ ∼ 4.1 × 10−3) at 10 GHz. A great thermal conductivity of 1.363 W/(m·K) at room temperature and high bending strength of 55.2 MPa could be achieved at 86 wt% filler loading. This study can provide a promising composite for microwave applications.

Hydrogen evolution and electric power generation through photoelectrochemical oxidation of cellulose dissolved in aqueous solution

Photoelectrochemical (PEC) cells capable of generating electricity or hydrogen through the oxidation of cellulose dissolved in an aqueous solution were constructed. As distinct from solid cellulose, the cellulose liquid fuel was beneficial for enabling a continuous reactant supply. Product analyses revealed that the cellulose macromolecules were cleaved to small organic acids and finally decomposed to CO2. During the electricity generation, the maximum power density of the PEC cell reached 1.13 mW cm−2. The influence of the photoelectrode structure on the PEC performance was elucidated. The monolithic structure of photoanodes consisting of an approximate monolayer of SrTiO3 particles anchored onto the backside metal layer provided a high photocurrent during oxygen evolution. The porous photoanode composed of heavily stacked TiO2 nanoparticles was found to be suitable for cellulose decomposition because of the high specific surface area. The present study should serve as a foundation for the direct energy utilization of waste biomass.

A sonochemical synthesis of SrTiO3 supported N-doped graphene oxide as a highly efficient electrocatalyst for electrochemical reduction of a chemotherapeutic drug.

A sonochemical based green synthesis method playa powerful role in nanomaterials and composite development. In this work, we developed a perovskite type of strontium titanate via sonochemical process. SrTiO3 particles were incorporated with nitrogen doped graphene oxide through simple ultrasonic irradiation method. The SrTiO3/NGO was characterized by various analytical methods. The nanocomposite of SrTiO3/NGO was modified with laser-induced graphene electrode (LIGE). The SrTiO3/NGO/LIGE was applied for electrochemical sensor towards chemotherapeutic drug detection (nilutamide). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques have been used to examine the electrochemical performance of nilutamide (anti-cancer drug). DPV was found to be more sensitive and found to exhibit a sensitivity 8.627 µA µM-1 cm-2 for SrTiO3/NGO/LIGE with a wide linear range (0.02-892µM) and low Limit of detection (LOD: 1.16µM). SrTiO3/NGO/LIGE has been examined for the detection of nilutamide in blood serum and urine samples and obtained a good recovery in the range of 97.2-99.72%. The enhanced stability and selectivity and practical application results indicates the suitability of SrTiO3/NGO/LIGE towards the detection of nilutamide drug in pharmaceutical industries.

Solar Panel Technologies for Light-to-Chemical Conversion.

ConspectusThe sustainable synthesis of fuels and chemicals is key to attaining a carbon-neutral economy. This can be achieved by mimicking the light-harvesting and catalytic processes occurring in plants. Solar fuel production is commonly performed via established approaches, including photovoltaic-electrochemical (PV-EC), photoelectrochemical (PEC), and photocatalytic (PC) systems. A recent shift saw these systems evolve into integrated, compact panels, which suit practical applications through their simplicity, scalability, and ease of operation. This advance has resulted in a suite of apparently similar technologies, including the so-called artificial leaves and PC sheets. In this Account, we compare these different thin film technologies based on their micro- and nanostructure (i.e., layered vs particulate), operation principle (products occurring on the same or different sides of the panel), and product/reaction scope (overall water splitting and CO2 reduction, or organics, biomass, and waste conversion).For this purpose, we give an overview of developments established over the past few years in our laboratory. Two light absorbers are generally required to overcome the thermodynamic challenges of coupling water oxidation to proton or CO2 reduction with good efficiency. Hence, tandem artificial leaves combine a lead halide perovskite photocathode with a BiVO4 photoanode to generate syngas (a mixture of H2 and CO), whereas PC sheets involve metal-ion-doped SrTiO3 and BiVO4 particles for selective formate synthesis from CO2 and water. On the other hand, only a single light absorber is needed for coupling H2 evolution to organics oxidation in the thermodynamically less demanding photoreforming process. This can be performed by immobilized carbon nitride (CNx) in the case of PC sheets or by a single perovskite light absorber in the case of PEC reforming leaves. Such systems can be integrated with a range of inorganic, molecular, and biological catalysts, including metal alloys, molecular cobalt complexes, enzymes, and bacteria, with low overpotentials and high catalytic activities toward selective product formation.This wide reaction scope introduces new challenges toward quantifying and comparing the performance of different systems. To this end, we propose new metrics to evaluate the performance of solar fuel panels based on the areal product rates and commercial product value. We further explore the key opportunities and challenges facing the commercialization of thin film technologies for solar fuels research, including performance losses over larger areas and catalyst/device recyclability. Finally, we identify emerging applications beyond fuels, where such light-driven panels can make a difference, including the waste management, chemical synthesis, and pharmaceutical industries. In the long term, these aspects may facilitate a transition toward a light-driven circular economy.

Optimization of Z-Scheme Photocatalytic Reactors for Solar Water Splitting

The U.S. Department of Energy recently announced its first Energy Earthshot on Clean Hydrogen, with a cost target of $1/kg-H2 by 2031. Assuming future utility-scale grid electricity prices from photovoltaics ($0.02/kWh), 80% of the cost of H2 would come from performing low-temperature water electrolysis at its thermoneutral voltage, with zero additional overpotential. This fact motivates alternative, less-expensive means of using light to generate mobile charge carriers than photovoltaics, and reactor designs with exceedingly low capital costs, like those we recently invented. Systems using low capital cost reactors benefit from low-voltage operation, which represents a paradigm shift from current state-of-the-art electrolyzers that aim to operate at high current densities. Analytical models predict that solar photocatalytic water splitting inherently operates at low voltages through use of an ensemble of optically thin photoabsorbers each operating at a low rate. Collectively the ensemble exhibits larger overall solar-to-hydrogen conversion efficiencies in comparison to optically thick designs. In efforts to attain these predicted higher efficiencies, we are performing detailed studies on the properties of state-of-the-art doped SrTiO3 and BiVO4 photocatalyst particles. During my talk, I will share our recent efforts in atomic-layer deposited ultrathin oxide coatings to impart redox selectivity and materials stability, single-photocatalyst-particle current–potential behavior and mobile charge carrier properties, and atomic-level information on dopant distributions and materials interfaces obtained from electron microscopies and X-ray spectroscopies. Collectively, our discoveries provide new design guidelines and additional research pathways for the development of effective composite materials to serve as active components in techno-economically viable artificial photosynthetic devices.

Improvement of dielectric constant and mechanical properties of thermoplastic polyurethanes using surface modified strontium titanate

AbstractRecently, the focus of research in electronic industry has shifted toward obtaining high‐charge‐storing materials. Inspired by the trends in recent technological advancements, we proposed to fabricate a promising composite with a high‐dielectric constant, high‐thermal stability, good mechanical property, and excellent resistance to stiffness. We used thermoplastic polyurethane (TPU) as the matrix and strontium titanate (SrTiO3) particles as a filler to obtain the required properties. To address the incompatibility between the TPU matrix and SrTiO3 particles, the surface of SrTiO3 particles was functionalized with isophorone diisocyanate (IPDI). The functionalization of SrTiO3 particles with IPDI molecules was confirmed through various investigations: Fourier transform infrared spectroscopy, thermogravimetric analysis, X‐ray photoelectron spectroscopy, and field emission scanning electron microscopy analysis were performed. Low‐speed melt extrusion methods were used to fabricate the composite materials. The composite materials possessed higher thermal stability, high‐dielectric constant (three times that of neat TPU at 1 MHz), and mechanical properties with high stiffness.

Preparing Sr-containing nano-structures on micro-structured titanium alloy surface fabricated by additively manufacturing to enhance the anti-inflammation and osteogenesis

The development of additive manufacturing technology has made it possible to customize joint implants. However, the fibrous tissue caused by long-term chronic inflammation delays bone regeneration. Moreover, the discovery of micro/nano-structure on the natural bone makes the study of implant surface morphology meaningful. In this study, a Sr-containing nano-structure on micro-structured titanium alloy surface was fabricated to enhanced the anti-inflammatory and osteogenic properties of implants. Ti6Al4V (TC4) alloys with micro-structured surface prepared by additive manufacturing were used as the material base model. Subsequently, spherical SrTiO3 particles were fabricated on the TC4 surfaces by hydrothermal treatment. The anti-inflammatory and osteogenic performance of smooth surface, micro-structured surface, Sr-containing nano-structured surface and Sr-containing micro/nano-structured surface were investigated. In vitro results exhibited that the macrophages cultured on micro/nano-structured surface were polarized to anti-inflammatory M2 phenotype and enhanced the expression of osteogenic growth factors. The Sr-containing micro/nano-structured surface effectively upgraded the proliferation and differentiation of SaOS-2 cells compared with other surfaces. Sr2+ and micro/nano-structure effectively enhanced the anti-inflammatory and osteogenic properties of titanium alloys. This finding suggested that the micro/nano-structured surface doped with bioactive elements is expected to broaden the horizons of biomedical materials. Data availabilityThe raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.

(Invited) Photo-SECM Measurements of Water Splitting at Single Semiconductor Particles

Understanding and improving the properties of photocatalysts can have important implications for energy conversion and storage. Because the activity of heterogeneous catalysts depends strongly on local atomic structures, probing (photo)catalytic reactions at specific local sites is critically important. We have recently reported the use of scanning electrochemical microscopy (SECM) for nanoscale imaging of photoelectrochemical processes at semiconductor surfaces. To illuminate a microscopic portion of the substrate surface facing the SECM probe, a glass-sealed, polished Pt tip simultaneously serves as a nanoelectrode and a light guide. In this paper, we present the results of first nanoscale SECM and photo-SECM experiments with single BiVO4 and SrTiO3 particles. Local mapping of oxygen and hydrogen fluxes produced by water splitting at single semiconductor particles was carried out using chemically modified SECM nanotips.