Ultrasonic-Induced Surface Disordering Promotes Photocatalytic Hydrogen Evolution of TiO.

Surface disordering has been considered an effective strategy for tailoring the charge separation and surface chemistry of semiconductor photocatalysts. A simple but reliable method to create surface disordering is, therefore, urgently needed for the development of high-performance semiconductor photocatalysts and their practical applications. Herein, we report that the ultrasonic processing, which is commonly employed in the dispersion of photocatalysts, can induce the surface disordering of TiO and significantly promote its performance for photocatalytic hydrogen evolution.

Kinetic pathways of sub-bandgap induced electron transfer in Ag/TiO and the effect on isopropanol dehydrogenation under gaseous conditions.

Electron transfer and its kinetics play a major role in the photocatalysis of metal/semiconductor systems. Using photoconductances, photoabsorption, and photoinduced spectroscopic techniques, the present research aimed to gain a deep insight into electron transfer pathways and their kinetics for Ag/TiO systems under sub-bandgap light illumination and gaseous conditions. The results revealed that electrons generated in TiO can transfer to Ag nanoparticles at fast rates, and plasmon-generated electrons in Ag nanoparticles can also transfer to TiO.

From heat to flavor: Unlocking new chemical signatures to discriminate Wuyi rock tea under light and moderate roasting.

Roasting is crucial for the distinct flavor of Wuyi rock tea (WRT). This study applied untargeted metabolomics to investigate the effects of roasting on 139 WRT samples roasted at light fire (LF) or moderate fire (MF) intensities. Compared to LF, MF roasting led to a decrease in the cis/trans flavanol ratio by 56% and theanine by 85%, while increasing the levels of N-ethyl-2-pyrrolidione-substituted flavanols (EPSFs), flavonol aglycones and flavone C-glycosides.

Grain Boundary Elimination via Recrystallization-Assisted Vapor Deposition for Efficient and Stable Perovskite Solar Cells and Modules.

Vapor deposition is a promising technology for the mass production of perovskite solar cells. However, the efficiencies of solar cells and modules based on vapor-deposited perovskites are significantly lower than those fabricated using the solution method. Emerging evidence suggests that large defects are generated during vapor deposition owing to a specific top-down crystallization mechanism.

Fermi-level shift, electron separation, and plasmon resonance change in Ag nanoparticle-decorated TiO under UV light illumination.

Noble metal nanoparticles are widely used as co-catalysts for storing and separating electrons in semiconductor photocatalysis. Thus, evaluating this ability is important and meaningful to understand the photocatalytic mechanism. Employing Ag nanoparticles, the present study combined photoconductance and theoretical analysis to evaluate the Fermi-level () shift in a UV-illuminated Ag/TiO system under gaseous conditions.

Metabolomics integrated with machine learning to discriminate the geographic origin of Rougui Wuyi rock tea.

The geographic origin of agri-food products contributes greatly to their quality and market value. Here, we developed a robust method combining metabolomics and machine learning (ML) to authenticate the geographic origin of Wuyi rock tea, a premium oolong tea. The volatiles of 333 tea samples (174 from the core region and 159 from the non-core region) were profiled using gas chromatography time-of-flight mass spectrometry and a series of ML algorithms were tested.

Facile Synthesis of Island-like ZrO-VO Composite Films with Enhanced Thermochromic Performance for Smart Windows.

VO-based film, as a very promising thermochromic material for smart windows, has attracted extensive attention but has not been widely applied because it is difficult to simultaneously improve in terms of both solar-modulation efficiency (Δ) and visible transmittance () when made using the magnetron-sputtering method, and it has poor durability when made using the wet chemical method. Herein, island-like ZrO-VO composite films with improved thermochromic performance (Δ: 12.6%, : 45.

Effect of Vacuum-Sealed Annealing and Ice-Water Quenching on the Structure and Photocatalytic Acetone Oxidations of Nano-TiO Materials.

In the current research, P25 TiO materials sealed in quartz vacuum tubes were subject to annealing and ice-water post-quenching, with the effects on TiO structures, morphology, and photocatalytic activity being studied. It is shown that the vacuum-sealed annealing can lead to a decrease in the crystallinity and temperature of anatase-to-rutile phase transition. A disorder layer is formed over TiO nanoparticles, and the TiO lattices are distorted between the disorder layer and crystalline core.

Effects of pruning on mineral nutrients and untargeted metabolites in fresh leaves of cv. Shuixian.

Pruning is an important strategy for increasing tea production. However, the effects of pruning on tea quality are not well understood. In this study, tea leaves were collected from Wuyi Mountain for both ionomic and metabolomic analyses.

Directed Accumulation of Nitrogen Metabolites through Processing Endows Wuyi Rock Tea with Singular Qualities.

The execution of specific processing protocols endows Wuyi rock tea with distinctive qualities produced through signature metabolic processes. In this work, tea leaves were collected before and after each of three processing stages for both targeted and untargeted metabolomic analysis. Metabolic profiles of processing stages through each processing stage of rotation, pan-firing and roasting were studied.

A light-heat synergism in the sub-bandgap photocatalytic response of pristine TiO: a study of diffusion reflectance and conductance.

Pristine TiO materials are mainly used as photocatalysts under super-bandgap light illumination. The sub-bandgap (SBG) photocatalytic response has seldom been investigated and the mechanism of action remains unclear. In the current research, we firstly study the SBG light electronic transition of pristine P25 TiO by means of diffusion reflectance and (photo)conductance measurements under finely controllable conditions.

Kinetics and energetic analysis of the slow dispersive electron transfer from nano-TiO to O by diffusion reflectance and Laplace transform.

Electron transfer to O is a universally existing process for the physiochemistry of many materials. Electron transfer to O is also an inevitable process for photocatalytic reactions over TiO and other materials. In the present research, a diffusion reflectance system was developed to measure optical diffusion reflectances caused by photoinduced electrons in nano-TiO under a steady light illumination; absorption decays can be obtained to study the electron transfer from their trapped states to O.

Acid Solution Processed VO-Based Composite Films with Enhanced Thermochromic Properties for Smart Windows.

As a typical thermochromic material, VO coatings can be applied to smart windows by modulating the transmission of near infrared (NIR) light via phase transition. However, the inherent undesirable luminous transmittance () and solar modulation efficiency (Δ) of pure VO impede its practical application. In order to solve this problem, the porous VO based composite film was prepared by magnetron sputtering and subsequent acid solution process with ZnVO particles used as a sacrificial template to create pores, which showed excellent (72.

The effect of Cu dopants on electron transfer to O and the connection with acetone photocatalytic oxidations over nano-TiO.

Modifying TiO with the Cu element has been shown to be useful for photocatalysis. Although it had been known that Cu species could trap electrons from TiO, whether they can affect the kinetics of electron transfer and how this can contribute to photocatalysis still remain unknown. In the current research, Cu-TiO samples were firstly prepared with a hydrothermal reaction and characterized in detail.

Preparation, Characterization, and Photocatalytic Properties of Self-Standing Pure and Cu-Doped TiO Nanobelt Membranes.

A traditional hydrothermal method was modified to synthesize ultra-long sodium titanate nanobelts by simultaneously stirring the solution. The ultra-long sodium titanate nanobelts were converted to hydrogen titanate nanobelts through an ion exchanging way. A method was then used to prepare self-standing flexible large-area membranes; they were then subject to post-annealing at different temperatures to obtain a self-standing TiO nanobelt membrane with a slight decrease in flexibility.

New Insights into the Fundamental Principle of Semiconductor Photocatalysis.

Although photocatalysis has been studied for many years as an attractive way to resolve energy and environmental problems, its principle still remains unclear. Some confusions and misunderstandings exist in photocatalytic studies. This research aims to elaborate some new thoughts on the fundamental principle of semiconductor photocatalysis.

Can Plasmonic Effect Cause an Increase in the Catalytic Reduction of -nitrophenol by Sodium Borohydride over Au Nanorods?

The catalytic reduction of -nitrophenol (4-NP) to 4-aminopyridine (4-AP) over Au nanoparticles can be increased by light illumination. Whether this is caused by the plasmonic effect remains unclear. The present research carried out a careful examination of the effects of light illumination and temperature on the catalytic conversion of 4-NP to 4-AP over Au nanorods.

Hydrothermal synthesis of delafossite CuScO hexagonal plates as an electrocatalyst for the alkaline oxygen evolution reaction.

In recent years, substantial efforts have been devoted to investigating the electrocatalytic activity of transition metal oxide catalysts, especially delafossite oxides have been proved to exhibit remarkable activity toward the oxygen evolution reaction (OER). Herein, the electrocatalytic activity and stability of CuScO hexagonal plates (around 3-4 μm) for the OER in alkaline solution were investigated. The micron sized CuScO with well-defined hexagonal plate morphology was prepared through a facile hydrothermal method.

CdS/ZnS Heterostructured Porous Composite with Enhanced Visible Light Photocatalysis.

Fabrication of semiconductor composites consisting of multicomponent or multiphase heterojunctions is a very effective strategy to design highly active photocatalyst systems. Here we present a facile design to fabricate novel CdS/ZnS heterostructured porous sheet-like nanocomposite based on a cation-exchanged hydrothermal procedure. Micro-structural analyses reveal that the product is a kind of heterostructured composite with porous structure and high crystallinity.

Effects of spatial topologies and electron Fermi-level gradient on the photocatalytic efficiency of nano-particulate semiconductors.

Nanocrystalline (nc) semiconductor materials are important in photocatalysis. The nanoparticle (NP) topologies and electron Fermi-level (E) gradient along the interconnected NPs affect the photocatalytic efficiency (η) of the nc-materials because of the charge carrier interparticle transport (IPT). However, the detailed physiochemical kinetic mechanism remains unclear.

The role of electron interfacial transfer in mesoporous nano-TiO photocatalysis: a combined study of in situ photoconductivity and numerical kinetic simulation.

In this research, a combination of in situ photoconductivity (σ) and kinetic simulations was used to study the role of electron interfacial transfer (IT) in the gaseous photocatalysis of formic acid by mesoporous nanocrystalline TiO. The effects of light intensity, initial formic acid concentrations, oxygen amounts, and temperature on the in situ σ and the photocatalytic courses were studied in detail. The temperature dependence of in situ σ clearly shows that the electron transfer is determined by the IT of electrons to O rather than by the transport.

A stochastic study of electron transfer kinetics in nano-particulate photocatalysis: a comparison of the quasi-equilibrium approximation with a random walking model.

In the photocatalysis of porous nano-crystalline materials, the transfer of electrons to O plays an important role, which includes the electron transport to photocatalytic active centers and successive interfacial transfer to O. The slowest of them will determine the overall speed of electron transfer in the photocatalysis reaction. Considering the photocatalysis of porous nano-crystalline TiO as an example, although some experimental results have shown that the electron kinetics are limited by the interfacial transfer, we still lack the depth of understanding the microscopic mechanism from a theoretical viewpoint.

Monte-Carlo modelling of nano-material photocatalysis: bridging photocatalytic activity and microscopic charge kinetics.

In photocatalysis, it is known that light intensity, organic concentration, and temperature affect the photocatalytic activity by changing the microscopic kinetics of holes and electrons. However, how the microscopic kinetics of holes and electrons relates to the photocatalytic activity was not well known. In the present research, we developed a Monte-Carlo random walking model that involved all of the charge kinetics, including the photo-generation, the recombination, the transport, and the interfacial transfer of holes and electrons, to simulate the overall photocatalytic reaction, which we called a "computer experiment" of photocatalysis.

Correlation of electron transport and photocatalysis of nanocrystalline clusters studied by Monte-Carlo continuity random walking.

In this research, Monte-Carlo Continuity Random Walking (MC-RW) model was used to study the relation between electron transport and photocatalysis of nano-crystalline (nc) clusters. The effects of defect energy disorder, spatial disorder of material structure, electron density, and interfacial transfer/recombination on the electron transport and the photocatalysis were studied. Photocatalytic activity is defined as 1/τ from a statistical viewpoint with τ being the electron average lifetime.