Three-Dimensional Lupinus-like TiO2 Nanorod@Sn3O4 Nanosheet Hierarchical Heterostructured Arrays as Photoanode for Enhanced Photoelectrochemical Performance

A 3D hierarchical TiO2/CaIn2S4/C3N4arrays photoanode with dual-heterojunction for enhanced photoelectrochemical performance

A novel 3D hierarchical TiO2/CaIn2S4/C3N4arrays with dual heterojunctions photoanode is constructed by stepwise deposition of CaIn2S4nanosheets and ultrathin C3N4onto the well-aligned TiO2nanorods arrays. Integrating the merit of the superior ability of CaIn2S4and C3N4to harvest visible light, dual type-Ⅱ heterojunction band structure and one-dimensional ordered nanostructures, the TiO2/CaIn2S4/C3N4photoanode exhibits simultaneous significant improvements in visible-light harvesting, charge separation and electron transfer capability. At 1.23 V (versus reversible hydrogen electrode) under AM 1.5 G irradiation, the TiO2/CaIn2S475/C3N4photoanode exhibits a photocurrent density of 4.5 mA cm-2, which is 5.2 and 51.1-fold higher than that of TiO2/CaIn2S475 and pristine TiO2photoanode, respectively. Moreover, the applied bias photo-to-current efficiency (ABPE) of the TiO2/CaIn2S475/C3N4photoanode reaches 3.5% at 0.36 V (versus reversible hydrogen electrode). These results are helpful for fabricating more efficient heterostructure photoelectrodes.

The Recent Development in Chemoresistive-Based Heterostructure Gas Sensor Technology, Their Future Opportunities and Challenges: A Review

Atmospheric pollution has become a critical problem for modern society; therefore, the research in this area continually aims to develop a high-performance gas sensor for health care and environmental safety. Researchers have made a significant contribution in this field by developing highly sensitive sensor-based novel selective materials. The aim of this article is to review recent developments and progress in the selective and sensitive detection of environmentally toxic gases. Different classifications of gas sensor devices are discussed based on their structure, the materials used, and their properties. The mechanisms of the sensing devices, identified by measuring the change in physical property using adsorption/desorption processes as well as chemical reactions on the gas-sensitive material surface, are also discussed. Additionally, the article presents a comprehensive review of the different morphologies and dimensions of mixed heterostructure, multilayered heterostructure, composite, core-shell, hollow heterostructure, and decorated heterostructure, which tune the gas-sensing properties towards hazardous gases. The article investigates in detail the growth and interface properties, concentrating on the material configurations that could be employed to prepare nanomaterials for commercial gas-sensing devices.

Ration design of 0D/3D Sn3O4/NiS nanocomposite for enhanced photocatalytic hydrogen generation

Developing economic and high-performance noble-metal-free photocatalysts is the key to realize efficient photocatalysis. In this work, NiS nanoparticles and hierarchical Sn3O4 nanostructures are tightly bonded by a two-step method combining...

Interfacial Charge Transport in 1D TiO2 Based Photoelectrodes for Photoelectrochemical Water Splitting

1D nanostructured photoelectrodes are promising for application as photoelectrochemical (PEC) devices for solar energy conversion into hydrogen (H₂ ) owing to the optical, structural, and electronic advantages. Titanium dioxide (TiO₂ ) is the most investigated candidate as a photoelectrode due to its good photostability, low production cost, and eco-friendliness. The obstacle for TiO₂ 's practical application is the inherent wide bandgap (UV-lights response), poor conductivity, and limited hole diffusion length. Here, a comprehensive review of the current research efforts toward the development of 1D TiO₂ based photoelectrodes for heterogeneous PEC water splitting is provided along with a discussion of nanoarchitectures and energy band engineering influences on interfacial charge transfer and separation of 1D TiO₂ composited with different dimensional photoactive materials. The key focus of this review is to understand the charge transfer processes at interfaces and the relationship between photogenerated charge separation and photoelectrochemical performance. It is anticipated that this review will afford enriched information on the rational designs of nanoarchitectures, doping, and heterojunction interfaces for 1D TiO₂ based photoelectrodes to achieve highly efficient solar energy conversion.

Mulberry-like BiVO4 architectures: synthesis, characterization and their application in photocatalysis

Mulberry-like BiVO₄ architectures were prepared by a facile solvothermal route. The obtained architectures showed enhanced light absorption, high photocatalytic properties, good stability and reusability.

Antigen down format photoelectrochemical analysis supported by fullerene functionalized Sn3O4

Herein, a smart competitive-type photoelectrochemical (PEC) sensor based on an antigen-down (Ag-down) format for procalcitonin (PCT) detection is proposed. A fullerene sensitized flower-like Sn₃O₄ nano-structure is used as the photoactive platform, and FeS₂ is labeled on the secondary antibody as a signal adjusting element. The sensor exhibits excellent sensitivity and great stability.

3D structured materials and devices for artificial photosynthesis

Artificial photosynthesis is an effective way to convert solar energy into fuels, which is of great significance to energy production and reduction of atmospheric CO₂ content. In recent years, 3D structured artificial photosynthetic system has made great progress as an effective design strategy. This review first highlights several typical mechanisms for improved artificial photosynthesis with 3D structures: improved light harvesting, mass transfer and charge separation. Then, we summarize typical examples of 3D structured artificial photosynthetic systems, including bioinspired structures, photonic crystals (PC), designed photonic structures (PC coupling structure, plasmon resonance structure, optical resonance structure, metamaterials), 3D-printed systems, nanowire integrated systems and hierarchical 3D structures. Finally, we discuss the problems and challenges to the application and development of 3D artificial photosynthetic system and the possible trends of future development. We hope this review can inspire more progress in the field of artificial photosynthesis.

Detection signal amplification strategies at nanomaterial-based photoelectrochemical biosensors

This review focusses on unique material modification and signal amplification strategies reported in developing photoelectrochemical biosensors with utmost sensitivity and selectivity.

Sn-doped hematite modified by CaMn2O4 nanowire with high donor density and enhanced conductivity for photocatalytic water oxidation

Herein, we report a novel nanocomposite consisting of n-type Sn-doped hematite and p-type CaMn₂O₄ nanowire (CaMn₂O₄/α-Fe₂O₃). The nanocomposite was characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), ultraviolet-visible absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), which showed that nanospindle-like Sn-doped hematite and CaMn₂O₄ nanowire contact intimately in the nanocomposite, resulting in efficient charge transfer and separation. Photoelectrochemical results reveal that the nanocomposite possesses higher donor density, enhanced conductivity and lower overpotential for dioxygen evolution. In addition, the nanocomposite demonstrates high photocatalytic activity for water oxidation to produce oxygen in a photoelectrochemical cell. The amount of O₂ evolved from the optimized photoanode of the photoelectrochemical cell was 1.98 μmol in 2 h of simulated sunlight irradiation. This work demonstrates a facile synthesis of a novel nanocomposite as anode material for photocatalytic water oxidation to produce O₂.

Vertically oriented Sn3O4 nanoflakes directly grown on carbon fiber cloth for high-performance lithium storage

Flexible electrodes of vertically oriented Sn₃O₄ nanoflakes grown on carbon fiber cloth were synthesized by a hydrothermal reaction, exhibiting superior electrochemical performance.

TiO2@Sn3O4 nanorods vertically aligned on carbon fiber papers for enhanced photoelectrochemical performance

Semiconductor heterostructures are regarded as an efficient way to improve the photocurrent in photoelectrochemical cell-type (PEC) photodetectors. To better utilize solar energy, TiO₂@Sn₃O₄ arrays vertically aligned on carbon fiber papers were synthesized via a hydrothermal route with a two-step method and used as photoanodes in a self-powered photoelectrochemical cell-type (PEC) photodetector under visible light. TiO₂@Sn₃O₄ heterostructures exhibit a stable photocurrent of 180 μA, which is a 4-fold increase with respect to that of the Sn₃O₄ nanoflakes on carbon paper, and a two-order increase with respect to that of the TiO₂ NRs arrays. The evolution of hydrogen according to the photo-catalytic water-splitting process showed that Sn₃O₄/TiO₂ heterostructures have a good photocatalytic hydrogen evolution activity with the rate of 5.23 μmol h⁻¹, which is significantly larger than that of Sn₃O₄ nanoflakes (0.40 μmol h⁻¹) and TiO₂ nanorods (1.13 μmol h⁻¹). Furthermore, the mechanism behind this was discussed. The detector has reproducible and flexible properties, as well as an enhanced photosensitive performance.

Semiconductor heterostructures are regarded as an efficient way to improve the photocurrent in photoelectrochemical cell-type (PEC) photodetectors.

"Metal oxide -based heterostructures for gas sensors"- A review

This review focuses on the synthesis and chemical sensing characterization of metal oxide heterostructures reported since 2012. Heterostructures exhibit strong interactions between closely packed interfaces, showing superior performances compared to single structures. Surface effects appear thanks to the magnification of nanostructures' surface leading to an enhancement of surface related properties (the base of chemical sensors working mechanism). The combination of different metal oxides to form heterostructures further improves the selectivity and/or other important sensing parameters. A very large number of different morphologies and structures have been proposed, each one exhibiting peculiar sensing properties towards specific chemical compounds. Among the different preparation methodologies, a significant number has been performed by means of hydrothermal method. However, the combination of various fabrication methods seems a very efficient strategy to obtain metal oxide-based heterostructures with different morphologies and dimensions such as core-shell nanostructures, one-dimensional heterostructures, two-dimensional layered heterojunctions, and three-dimensional hierarchical heterostructures. Despite all extraordinary advances in both material science and nanotechnology and the results achieved with heterostructured chemical sensors, there are few points that still deserve further studies and investigations, such as possible diffusion across the junctions, reproducibility of the fabrication process, synergistic or catalytic effects among the materials forming the heterostructures and influence/stability of the contacts. Moreover, perfect control over their growth is mandatory for their application in commercial devices. Only a careful understanding of the growth and the interface properties could fill the existing gap between laboratory studies and real-world exploitation of these heterostructures.