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Sodium-oxygen batteries are emerging as a new energy storage system because of their high energy density and low cost. However, the cycling performance of the battery is not satisfying due to its insulating discharge product. Here, we synthesized metallic phosphides with gradient concentration (g-CoNiFe-P) and their uniform counterpart (CoNiFe-P) as cathode catalysts in a Na–O2battery. Notably, the distribution of relaxation time (DRT) was utilized to identify the rate-determining step in a Na–O2battery, evaluate the catalytic performance of the catalysts, and monitor the change of every single electrochemical process along the whole cycling process to study the degradation mechanism. The g-CoNiFe-P catalyst presented better initial capacity and cycling performances. The evolution of the kinetic processes resulting in battery degradation has been investigated by DRT analysis, which assists with characterizations. Our work demonstrates the application of DRT in battery diagnosis to evaluate the catalytic performance of catalysts and monitor the changes in different kinetic processes of new energy systems.

NaO2batteries have garnered increasing attention due to their high energy density and the abundance of sodium resources. However, the lack of efficient air cathodes has hindered their practical application, preventing the realization of stable and long cycling lifespans. Herein, we report the NaO2batteries using Fe-doped CoP nanowire arrays on carbon cloth (FeCoP-CC) as the air cathode, which exhibit a low overpotential of 200 mV, a high discharge specific capacity of 2853 mAh g−1, and stable cycling performance over 200 cycles at a current density of 200 mA g−1. The exceptional electrochemical performance can be attributed to the optimized adsorption of oxygen species by FeCoP-CC, which forms film-like NaO2discharge products that facilitate the oxygen transport channels. Furthermore, the film-like discharge products and the extensive contact interface with the cathode accelerate charge transfer and effectively decompose during subsequent charging processes. This work provides valuable insights into the rational design of electrocatalytic air cathodes.

The study of gold (Au) nanoclusters (NCs) as effective co-catalysts has attracted considerable research interests in photoelectrocatalysis. However, it is still a challenge to design an Au NC-hybridized photoelectrode, which exhibits both high performance, particularly in photoelectrocatalytic full water splitting, and long-term photostability. Herein, we present a simple and efficient synthesis strategy for boosting the photoelectrochemical performance and photostability of TiO2nanowire arrays (NWAs) by loading l-cysteine-capped Au25NCs (Au25(Cys)18) followed by coating a TiO2thin layer via atomic layer deposition (ALD). We revealed that a ligand detaching process had occurred, i.e., the cysteine ligands on Au25NCs was in situ etched and Au25NCs were covered by the protective TiO2shell in the ALD process, which effectively restricted the loss and size growth of the NCs on the TiO2surface. Consequently, the designed core–shell structural TiO2@Au25/TiO2showed a photocurrent density of 1.35 mA/cm2at 1.23 V versus RHE, almost 330% of that for the pristine TiO2NWAs. Besides, it could produce H2and O2at a stoichiometric ratio with a favorable rate for PEC full water splitting under simulated solar light irradiation. The nanostructure and the photostability of the composite photoelectrode were well-retained during a long-term recycling test for generation of gases. The rationally designed core–shell structural photoanode provides a facile method for preparation of Au NC-based composite photocatalysts, which is facing the efficient photoelectrochemical water splitting for hydrogen energy production and other potential applications in solar energy conversion.

Graphene oxide (GO), a common intermediate for making graphene-like materials from graphite, was recently found to possess an explosive fire hazard that can jeopardize the GO’s large-scale production and wide applications. This work reports a simple and facile method to cross-link the GO with Al3+cations, in one step, into a freestanding flexible membrane. This inorganic membrane resists in-air burning on an open flame, at which non-cross-linked GO was burnt out within ∼5 s. All characterization data suggested that the in situ “epoxy ring-opening” reactions on the GO surface facilitated the cross-linking, which elucidated a new mechanism for the generalized inorganic polymerization. With the much improved thermal and water stabilities, the cross-linked GO film can help to advance high-temperature fuel cells, electronic packaging, etc. as one of the long-sought inorganic polymers known to date.

Abstract: Investigation of early stages of crystal growth revealed that crystal growth in some systems may not follow the classic route. In the early stages of inorganic crystal growth, precursor molecules and/or nanocrystallites may aggregate into large and disordered particles with the assistance of some polymers or biomolecules. Surface crystallization of these aggregates would then take place to form shells with high crystallinity and density, followed by an extension of the crystallization from surface to core. This so-called reversed crystal growth mechanism has been found in crystallization of several inorganic compounds including zeolites, perovskites, metals and metal oxides, and will be identified in more material systems. The establishment of this new crystal growth route gave us more freedom to control the morphology of crystals and to understand the formation mechanism of many natural minerals. This article gives a brief review of the recent research in this field by featuring some typical examples of the reversed crystal growth.

Traditional Chinese medicines (TCMs), a key branch of natural medicines, play an important role in the treatment of diseases because of their reliable clinical performance. Identification of their active compounds constitutes a bottleneck in the development of TCMs. Screening and analysis of active compounds is a challenge in TCM research. This review summarizes recent progress in the development of biological fingerprinting strategies for screening and analyzing bioactive compounds in TCMs using molecular recognition, metabolism and omics tools. The evaluated strategies include the following techniques: microdialysis/centrifugal ultrafiltration-HPLC, biochromatography, metabolic fingerprinting analysis, 2-dimensional biochromatography and omics fingerprinting analysis.

This study investigates the effects of various dosages of belite replacing ordinary Portland cement (OPC) on properties of OPC binders using carbonation curing. Mechanical strength was examined, pore-related test and microstructural/mineralogical analyses including water absorption, scanning electron microscopy (SEM), thermogravimetric analysis and 29Si nuclear magnetic resonance (29Si-NMR) were carried out. Extra attention was paid on the changes in the thickness and porosity of interfacial transition zone (ITZ) of mortars. Compared to normal curing, carbonation curing increased the compressive strength of all mortar mixes, especially given a longer period of curing and/or with belite addition. The greatest increase (73.18%) in the compressive strength was seen in the specimen with 35% of belite after 28 days of carbonation curing compared its peer under normal curing condition. Besides, specimens with 5% and 15% belite obtained higher flexural strength than that of the control after 7 and 28 days of carbonation curing. Carbonation curing led to about 92.75% increment in the flexural strength of the specimen with 15% belite. Regardless of curing conditions, in most cases, belite modified mortars had higher fractural toughness, probably due to the formation of more C-S-H gels instead of Portlandite. Compressive and flexural strength are more sensitive towards the thickness of ITZ than its porosity and carbonation curing strengthened this sensitivity. Carbonation curing densified the bulk OPC binders, especially after a long period of curing incorporated with belite. Microstructural analyses indicate that although in general belite hinders the hydration process of OPC, a suitable amount (5 wt.%) improved the hydration degree of OPC when cured in carbonation environment. The polymerization degree of C-S-H gels could be enhanced when belite is added irrespective of curing conditions.

Rechargeable Li–CO2batteries as a novel system developed in recent years directly use CO2as the reactant, which enables deeper penetration of energy storage and CO2utilization. The Li–CO2battery system, however, is at an early stage, and many challenges remained to be overcome urgently, especially the problem of high over-potential during the charging process. Here, we report a redox mediator, phenoxathiin, to assist the decomposition of Li2CO3during the charging process, which effectively reduces the over-potential and improves the cycling performance of the battery. Furthermore, we detect the presence of singlet oxygen during the oxidation of Li2CO3by phenoxathiin, which reveals more of the underlying science of the reaction mechanism of the Li–CO2battery.

The use of nanoparticles has drawn special attention, particularly in the treatment of plant diseases. Cymbidium mosaic virus (CymMV) and Odontoglossumring spot virus (ORSV) are the most prevalent and serious diseases that affect the development of the orchid industry. In this study we treated nanoparticles as a strategy for enhancing the resistance of orchids against CymMV and ORSV. After chitosan-modified gold nanoparticles (Au NPs) were injected into Phalaenopsisleaves, the injected leaves were exposed to 980 nm laser for light-heat conversion. To evaluate virus elimination in the treated Phalaenopsisleaves, the transcripts of coat protein genes and the production of viral proteins were assessed by reverse transcription-Polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. The expression of coat protein genes for both CymMV and ORSV was significantly lower in the chitosan-modified Au NP-treated Phalaenopsisleaves than in the control. Similarly, the amount of coat proteins for both viruses in the Phalaenopsisleaves was lower than that in the control (without nanoparticle injection). We propose that the temperature increase in the chitosan-modified Au NP-treated Phalaenopsistissues after laser exposure reduces the viral population, consequently conferring resistance against CymMV and ORSV. Our findings suggest that the application of chitosan-modified Au NPs is a promising new strategy for orchid virus therapy.