NiO Nanofibers as a Candidate for a Nanophotocathode

p-type NiO nanofibers have been synthesized from a simple electrospinning and sintering procedure. For the first time, p-type nanofibers have been electrospun onto a conductive fluorine doped tin oxide (FTO) surface. The properties of the NiO nanofibers have been directly compared to that of bulk NiO nanopowder. We have observed a p-type photocurrent for a NiO photocathode fabricated on an FTO substrate

Recent strategies for constructing efficient interfacial solar evaporation systems

Interfacial solar evaporation (ISE) is a promising technology to relieve worldwide freshwater shortages owing to its high energy conversion efficiency and environmentally sustainable potential. So far, many innovative materials and evaporators have been proposed and applied in ISE to enable highly controllable and efficient solar-to-thermal energy conversion. With rational design, solar evaporators can achieve excellent energy management for lowering energy loss, harvesting extra energy, and efficiently utilizing energy in the system to improve freshwater production. Beyond that, a strategy of reducing water vaporization enthalpy by introducing molecular engineering for water-state regulation has also been demonstrated as an effective approach to boost ISE. Based on these, this article discusses the energy nexus in two-dimensional (2D) and three-dimensional (3D) evaporators separately and reviews the strategies for design and fabrication of highly efficient ISE systems. The summarized work offers significant perspectives for guiding the future design of ISE systems with efficient energy management, which pave pathways for practical applications

A new operando surface restructuring pathway via ion-pairing of catalyst and electrolyte for water oxidation

The highly efficient and stable electrolysis needs the rational control of the catalytically active interface during the reactions. Here we report a new operando surface restructuring pathway activated by pairing catalyst and electrolyte ions. Using SrCoO3-δ-based perovskites as model catalysts, we unveil the critical role of matching the catalyst properties with the electrolyte conditions in modulating catalyst ion leaching and steering surface restructuring processes toward efficient oxygen evolution reaction catalysis in both pH-neutral and alkaline electrolytes. Our results regarding multiple perovskites show that the catalyst ion leaching is controlled by catalyst ion solubility and anions of the electrolyte. Only when the electrolyte cations are smaller than catalyst's leaching cations, the formation of an outer amorphous shell can be triggered via backfilling electrolyte cations into the cationic vacancy at the catalyst surface under electrochemical polarization. Consequently, the current density of reconstructed SrCoO3-δ is increased by 21 folds compared to the pristine SrCoO3-δ at 1.75 V vs. reversible hydrogen electrode and outperforms the benchmark IrO2 by 2.1 folds and most state-of-the-art electrocatalysts in the pH-neutral electrolyte. Our work could be a starting point to rationally control the electrocatalyst surface restructuring via matching the compositional chemistry of the catalyst with the electrolyte properties

Surface hydrophilicity mediated migration of nano/microparticles under temperature gradient in a confined space

Hypothesis: Particle transport by a temperature gradient is prospective in many biomedical applications. However, the prevalence of boundary confinement in practical use introduces synergistic effects of thermophoresis and thermo osmosis, causing controversial phenomena and great difficulty in understanding the mechanisms. Experiments: We developed a microfluidic chip with a uniform temperature gradient and switchable sub strate hydrophilicity to measure the migrations of various particles (d = 200 nm 2 lm), through which the effects of particle thermophoresis and thermo osmotic flow from the substrate surface were decou pled. The contribution of substrate hydrophilicity on thermo osmosis was examined. Thermophoresis was measured to clarify its dependence on particle size and hydrophilicity. Findings: This paper reports the first experimental evidence of a large enthalpy dependent thermo osmotic mobility chi similar to Delta H on a hydrophobic polymer surface, which is 1 2 orders of magnitude larger than that on hydrophilic surfaces. The normalized Soret coefficient for polystyrene particles, ST/ d = 18.0 K 1 mu m( 1), is confirmed to be constant, which helps clarify the controversy of the size dependence. Besides, the Soret coefficient of hydrophobic proteins is approximately four times larger than that of hydrophilic extracellular vesicles. These findings suggest that the intrinsic slip on the hydrophobic surface could enhance both surface thermoosmosis and particle thermophoresis. (c) 2023 Elsevier Inc. All rights reserved

Template-free fabrication of CdMoO4 hollow spheres and their morphology-dependent photocatalytic property

A facile and additive-free aqueous route is developed to the controllable synthesis of CdMoO4 hollow microspheres in a large scale. No templates or additives were involved in the reaction process. The microstructure of the spheres can be readily tuned by simply adjusting experimental parameters. Moreover, the as-prepared product exhibit significant morphology-depended photocatalytic activity. The present work will be not only helpful in systematically explore fabrication of hollow architectures but also provides new insights into morphology-controllable design of photocatalytic materials for their applications

Impact of Spontaneously Adsorbed Hydroxide Ions on Emulsification via Solvent Shifting

In this study, the influence of interfacial OH ions on spontaneous emulsification of a hexadecane–acetone–water system via the Ouzo effect (solvent shifting) was investigated. It was found that although there is no surfactant utilized in the solvent shifting method, the resulting emulsion droplets are negatively charged in a wide pH range (pH > ∼2.4) due to the spontaneous adsorption of OH ions. The OH ions remarkably affect the size, size distribution, and stability of the emulsions. The emulsion droplets obtained in the absence of OH ions are large and have a wide size distribution. Coalescence of the emulsion droplets and phase separation are prone to take place. At high OH^– concentration, the resulting emulsion droplets have a small size, a narrow size distribution, and excellent colloid stability. The results suggest that the spontaneous OH^– adsorption affects the nucleation process during the emulsification and the stability of the obtained emulsions during storage

A photothermal reservoir for highly efficient solar steam generation without bulk water

A solid photothermal reservoir is designed to implement solar-steam generation in the absence of bulk water. The photothermal reservoir is composed of a water absorbing core encapsulated by a photothermal reduced graphene oxide based aerogel sheet which absorbs light and converts it into heat thus evaporating the stored water. The photothermal reservoir is able to store 6.5 times its own weight in water, which is sufficient for one day solar evaporation, thus no external water supplement is required. During solar-steam generation, since no bulk water is involved, the photothermal reservoir minimizes heat conduction loss, and maximizes both of the exposed evaporation surface area and net energy gain from the environment, leading to an energy efficiency beyond the theoretical limit. An extremely high water evaporation rate of 4.0 kg m−2 h−1 (normalized to projection area) is achieved in laboratory studies over a cylinder photothermal reservoir with a diameter of 5.2 cm and a height of 15 cm under 1.0 sun irradiation. Practical evaluation of the photothermal reservoir outdoors as part of a desalination device demonstrates a similar evaporation rate where the salinity of the clean water produced is lower than 24 ppb. Thus the photothermal reservoir shows great potential for real world applications in portable solar-thermal desalination.</p

A bioinspired microreactor with interfacial regulation for maximizing selectivity in a catalytic reaction

We report a bioinspired emulsion microreactor composed of an electrical double layer to mimic the functions of cell membranes. This "artificial cell"can modulate the phase-oriented transport of reagents at the oil-liquid interface via the electrical double layer, affording a powerful tool to optimize the selectivity in a catalytic reaction. This journal is </p