2D Metal-Organic Framework Nanosheets based on Pd-TCPP as Photocatalysts for Highly Improved Hydrogen Evolution.

In this report, a 2D MOF nanosheet derived Pd single-atom catalyst, denoted as Pd-MOF, was fabricated and examined for visible light photocatalytic hydrogen evolution reaction (HER). This Pd-MOF can provide a remarkable photocatalytic activity (a H2 production rate of 21.3 mmol/gh in the visible range), which outperforms recently reported Pt-MOFs (with a H2 production rate of 6.6 mmol/gh) with a similar noble metal loading. Notably, this high efficiency of Pd-MOF is not due to different chemical environment of the metal center, nor by changes in the spectral light absorption. The higher performance of the Pd-MOF in comparison to the analogue Pt-MOF is attributed to the longer lifetime of the photogenerated electron-hole pairs and higher charge transfer efficiency.

Visualization of charge carriers in photocatalysts.

Surface photovoltage techniques combined with time-resolved spectroscopy methods provide an effective way to visualize the charge transfer dynamics in photocatalytic reactions.

Confined Heterojunction in Hollow-Structured TiO2 and Its Directed Effect in Photodriven Seawater Splitting.

The high salinity of seawater often strongly affects the activity and stability of photocatalysts utilized for photodriven seawater splitting. The current investigation is focused on the photocatalyst H-TiO2/Cu2O, comprised of hydroxyl-enriched hollow mesoporous TiO2 microspheres containing incorporated Cu2O nanoparticles. The design of H-TiO2/Cu2O is based on the hypothesis that the respective hollow and mesoporous structure and hydrophilic surfaces of TiO2 microspheres would stabilize Cu2O nanoparticles in seawater and provide efficient and selective proton adsorption. H-TiO2/Cu2O shows hydrogen production performances of 45.7 mmol/(g·h) in simulated seawater and 17.9 mmol/(g·h) in natural seawater, respectively. An apparent quantum yield (AQY) in hydrogen production of 18.8% in water (and 14.9% in natural seawater) was obtained at 365 nm. Moreover, H-TiO2/Cu2O displays high stability and can maintain more than 90% hydrogen evolution activity in natural seawater for 30 h. A direct mass- and energy- transfer mechanism is proposed to clarify the superior performance of H-TiO2/Cu2O in seawater splitting.

Dual Pd-Acid Sites Confined in a Hierarchical Core-Shell Structure for Hydrogenation of Nitrobenzene.

A core-shell structured Pd@TS-1@meso-SiO2 catalyst with confined Pd nanometals has been fabricated by one-pot synthesis, impregnation method and sol-gel method. With the promotion of acid sites and protection of mesoporous silica shell, Pd@TS-1@meso-SiO2 shows higher activity than commercial comparison and higher stability than sample without mesoporous silica shell in the hydrogenation of nitrobenzene. The schematic illustration of the synergy effect is also proposed.

Spontaneous Dewetting of Au-Thin Layers on Oxide- and Fluorine-Terminated Single Crystalline Anatase and Efficient Use in Photocatalytic H2 Production.

In the present work, the spontaneous dewetting of thin Au layers on single crystalline anatase nanosheets into narrow-disperse Au nanoparticles is investigated. Patterns of the Au particles can be formed on the main facets of anatase that provide a high co-catalytic activity for photocatalytic generation of H2 . Dewetting is distinctly influenced by the respective facets (001) and (101), the deposit thickness, and secondary thermal dewetting, but most strongly by the surface termination of the nanosheets. Fluoride termination not only leads to an enhanced Au-phobic behavior but strongly affects the co-catalytic activity for photocatalytic generation of H2 . While fluoride termination with or without Au decoration is detrimental for hole transfer, the interplay of the Au co-catalyst and surface fluoride yields highly beneficial effect for electron transfer. This results in a three-times higher photocatalytic H2 production for the F-terminated surface. The findings suggest that dewetting of Au on surface fluorinated TiO2 is an effective way to modulate surface dewetting and achieve a strongly enhanced photocatalytic activity.

Hierarchically Porous Few-Layer Carbon Nitride and Its High H+ Selectivity for Efficient Photocatalytic Seawater Splitting.

Photocatalysts for seawater splitting are severely restricted because of the presence of multiple types of ions in seawater that cause corrosion and deactivation. As a result, new materials that promote adsorption of H+ and hinder competing adsorption of metal cations should enhance utilization of photogenerated electrons on the catalyst surface for efficient H2 production. One strategy to design advanced photocatalysts involves introduction of hierarchical porous structures that enable fast mass transfer and creation of defect sites that promote selective hydrogen ion adsorption. Herein, we used a facile calcination method to fabricate the macro-mesoporous C3N4 derivative, VN-HCN, that contains multiple nitrogen vacancies. We demonstrated that VN-HCN has enhanced corrosion resistance and elevated photocatalytic H2 production performance in seawater. Experimental results and theoretical calculations reveal that enhanced mass and carrier transfer and selective adsorption of hydrogen ions are key features of VN-HCN that lead to its high seawater splitting activity.

Hierarchical zeolites containing embedded Cd0.2Zn0.8S as a photocatalyst for hydrogen production from seawater.

Uncovering an efficient and stable photocatalytic system for seawater splitting is a highly desirable but challenging goal. Herein, Cd0.2Zn0.8S@Silicalite-1 (CZS@S-1) composites, in which CZS is embedded in the hierarchical zeolite S-1, were prepared and show remarkably high activity, stability and salt resistance in seawater.

Imidazo[1,2-a]pyridine Derivatives as AMPK Activators: Synthesis, Structure-Activity Relationships, and Regulation of Reactive Oxygen Species in Renal Fibroblasts.

Adenosine 5'-monophosphate activated protein kinase (AMPK) has emerged as a promising target for the discovery of drugs to treat diabetic nephropathy (DN). Herein, a series of imidazo[1,2-a]pyridines were designed and synthesized. Among them, the active compound (EC50 =11.0 nM) showed good enzyme activation and molecular docking results showed hydrogen bonding interactions with the key amino acids Asn111 and Lys29 in the active site. Meanwhile, further cellular level experiments revealed that it could reduce reactive oxygen species (ROS) levels in NRK-49F cells induced by high glucose, and Western Blot experiments also demonstrate that it can increase the levels of p-AMPK and p-ACC and decrease the levels of TGF-ß1. The results of this study extend the structural types of AMPK activators and provide novel lead compounds for the subsequent development.

MEK1-dependent MondoA phosphorylation regulates glucose uptake in response to ketone bodies in colorectal cancer cells.

The Mondo family transcription factor MondoA plays a pivotal role in sensing metabolites, such as glucose, glutamine, and lactic acid, to regulate glucose metabolism and cell proliferation. Ketone bodies are important signals for reducing glucose uptake. However, it is unclear whether MondoA functions in ketone body-regulated glucose transport. Here we reported that ketone bodies promoted MondoA nuclear translocation and binding to the promoter of its target gene TXNIP. Ketone bodies reduced glucose uptake, increased apoptosis and decreased proliferation of colorectal cancer cells, which was impeded by MondoA knockdown. Moreover, we identified MEK1 as a novel component of the MondoA protein complex using a proteomic approach. Mechanistically, MEK1 interacted with MondoA and enhanced tyrosine 222, but not serine or threonine, phosphorylation of MondoA, inhibiting MondoA nuclear translocation and transcriptional activity. Ketone bodies decreased MEK1-dependent MondoA phosphorylation by blocking MondoA and MEK1 interaction, leading to MondoA nuclear translocation, TXNIP transcription, and inhibition of glucose uptake. Therefore, our study not only demonstrated that ketone bodies reduce glucose uptake, promote apoptosis, and inhibit cell proliferation in colorectal cancer cells by regulating MondoA phosphorylation but also identified MEK1-dependent phosphorylation as a new mechanism to manipulate MondoA activity.

Interfacial Carbon Makes Nano-Particulate RuO2 an Efficient, Stable, pH-Universal Catalyst for Splitting of Seawater.

An electrocatalyst composed of RuO2 surrounded by interfacial carbon, is synthesized through controllable oxidization-calcination. This electrocatalyst provides efficient charge transfer, numerous active sites, and promising activity for pH-universal electrocatalytic overall seawater splitting. An electrolyzer with this catalyst gives current densities of 10 mA cm-2 at a record low cell voltage of 1.52 V, and shows excellent durability at current densities of 10 mA cm-2 for up to 100 h. Based on the results, a mechanism for the catalytic activity of the composite is proposed. Finally, a solar-driven system is assembled and used for overall seawater splitting, showing 95% Faraday efficiency.

A spatial homojunction of titanium vacancies decorated with oxygen vacancies in TiO2 and its directed charge transfer.

The n-p homojunction design in semiconductors could enable directed charge transfer, which is promising but rarely reported. Herein, TiO2 with a spatial n-p homojunction has been designed by decorating TiO2 nanosheets with Ti vacancies around nanostructured TiO2 with O vacancies. 2D 1H TQ-SQ MAS NMR, EPR and XPS show the junction of titanium vacancies and oxygen vacancies at the interface. This spatial homojunction contributes to a significant enhancement in photoelectrochemical and photocatalytic performance, especially photocatalytic seawater splitting. Density functional theory calculations of the charge density reveal the directional n-p charge transfer path at the interface, which is proposed at the atomic-/nanoscale to clarify the generation of rational junctions. The spatial n-p homojunction provides a facile strategy for the design of high-performance semiconductors.

Design and synthesis of TiO2/C nanosheets with a directional cascade carrier transfer.

Directed transfer of carriers, akin to excited charges in photosynthesis, in semiconductors by structural design is challenging. Here, TiO2 nanosheets with interlayered sp2 carbon and titanium vacancies are obtained by low-temperature controlled oxidation calcination. The directed transfer of carriers from the excited position to Ti-vacancies to interlayered carbon is investigated and proven to greatly increase the charge transport efficiency. The TiO2/C obtained demonstrates excellent photocatalytic and photoelectrochemical activity and significant lithium/sodium ion storage performance. Further theoretical calculations reveal that the directional excited position/Ti-vacancies/interlayered carbon facilitate the spatial inside-out cascade electron transfer, resulting in high charge transfer kinetics.

Titanium Vacancies in TiO2 Nanofibers Enable Highly Efficient Photodriven Seawater Splitting.

Invited for the cover of this issue are Xiao-Yu Yang and co-workers at Wuhan University of Technology, Heinrich-Heine-Universität Düsseldorf, University of the Witwatersrand, and Ben-Gurion University of the Negev. The image depicts Ti vacancies in TiO2 as powerful drivers of photo- and photo-electrocatalytic seawater splitting for hydrogen production. Read the full text of the article at 10.1002/chem.202101817.

Titanium Vacancies in TiO2 Nanofibers Enable Highly Efficient Photodriven Seawater Splitting.

Photodriven seawater splitting is considered to be one of the most promising techniques for sustainable hydrogen production. However, the high salinity of seawater would deactivate catalysts and consume the photogenerated carriers. Metal vacancies in metal oxide semiconductors are critical to directed electron transfer and high salinity resistance; they are thus desirable but remain a challenge. We demonstrate a facile controllable calcination approach to synthesize TiO2 nanofibers with rich Ti vacancies with excellent photo/electro performances and long-time stability in photodriven seawater splitting, including photocatalysis and photo-electrocatalysis. Experimental measurements and theoretical calculations reveal the formation of titanium vacancies, as well as unidirectional electron trap and superior H+ adsorption ability for efficient charge transfer and resistance to corrosion by seawater. Therefore, atomic-/nanoscale characteristics and mechanism have been proposed to clarify the generation of titanium vacancies and the corresponding interfacial electron transfer.

The Role of Mondo Family Transcription Factors in Nutrient-Sensing and Obesity.

In the past several decades obesity has become one of the greatest health burdens worldwide. Diet high in fats and fructose is one of the main causes for the prevalence of metabolic disorders including obesity. Promoting brown or beige adipocyte development and activity is regarded as a potential treatment of obesity. Mondo family transcription factors including MondoA and carbohydrate response element binding protein (ChREBP) are critical for nutrient-sensing in multiple metabolic organs including the skeletal muscle, liver, adipose tissue and pancreas. Under normal nutrient conditions, MondoA and ChREBP contribute to maintaining metabolic homeostasis. When nutrient is overloaded, Mondo family transcription factors directly regulate glucose and lipid metabolism in brown and beige adipocytes or modulate the crosstalk between metabolic organs. In this review, we aim to provide an overview of recent advances in the understanding of MondoA and ChREBP in sensing nutrients and regulating obesity or related pathological conditions.

Spatial acid-base-Pd triple-sites of a hierarchical core-shell structure for three-step tandem reaction.

Spatial catalytic acid-base-Pd triple-sites of a hierarchical core-shell structure have been successfully constructed for a three-step reaction, and exhibited excellent catalytic activity and stability. A catalytic mechanism has been systematically studied via single one- and two-step reactions, and possible molecular reactions have been proposed.

Spatial Heterojunction in Nanostructured TiO2 and Its Cascade Effect for Efficient Photocatalysis.

A highly efficient photoenergy conversion is strongly dependent on the cumulative cascade efficiency of the photogenerated carriers. Spatial heterojunctions are critical to directed charge transfer and, thus, attractive but still a challenge. Here, a spatially ternary titanium-defected TiO2@carbon quantum dots@reduced graphene oxide (denoted as VTi@CQDs@rGO) in one system is shown to demonstrate a cascade effect of charges and significant performances regarding the photocurrent, the apparent quantum yield, and photocatalysis such as H2 production from water splitting and CO2 reduction. A key aspect in the construction is the technologically irrational junction of Ti-vacancies and nanocarbons for the spatially inside-out heterojunction. The new "spatial heterojunctions" concept, characteristics, mechanism, and extension are proposed at an atomic-/nanoscale to clarify the generation of rational heterojunctions as well as the cascade electron transfer.

Comparison of [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer.

PURPOSE: We evaluated the potential usefulness of [68Ga]Ga-DOTA-FAPI-04 positron emission tomography/computed tomography (PET/CT) for the diagnosis of primary and metastatic lesions in various types of cancer, compared with [18F] FDG PET/CT. METHODS: A total of 75 patients with various types of cancer underwent contemporaneous [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT either for an initial assessment or for recurrence detection. Tumour uptake was quantified by the maximum standard uptake value (SUVmax). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of [18F] FDG and [68Ga]Ga-DOTA-FAPI-04 PET/CT were calculated and compared to evaluate the diagnostic efficacy. RESULTS: The study cohort consisted of 75 patients (47 males and 28 females; median age, 61.5 years; age range, 32-85 years). Fifty-four patients with 12 different tumour entities underwent paired [68Ga]Ga-DOTA-FAPI-04 and [18F] FDG PET/CT for initial assessment, while the other 21 patients underwent paired scans for recurrence detection. [68Ga]Ga-DOTA-FAPI-04 PET/CT was able to clearly identify 12 types of malignant tumours with favourable tumour-to-background contrast, which resulted in a higher detection rate of primary tumours than did [18F] FDG PET/CT (98.2% vs. 82.1%, P = 0.021). Meanwhile, [68Ga]Ga-DOTA-FAPI-04 PET/CT showed a better sensitivity than [18F] FDG PET/CT in the detection of lymph nodes (86.4% vs. 45.5%, P = 0.004) and bone and visceral metastases (83.8% vs. 59.5%, P = 0.004). CONCLUSION: [68Ga]Ga-DOTA-FAPI-04 PET/CT showed a superior diagnostic efficacy than [18F] FDG PET/CT for the diagnosis of primary and metastatic lesions in patients with various types of cancer, especially in identifying liver metastases, peritoneal carcinomatosis, and brain tumours.

Hydrogen Evolution Enhancement over a Cobalt-Based Schottky Interface.

A proof-of-concept strategy for significant enhancement of hydrogen evolution reaction (HER) performance of transition metals via construction of a metal/semiconductor Schottky junction is presented. The decoration of low-cost commercial TiO2 nanoparticles on the surface of microscale Co dendrites causes a significant charge transfer across the Co/TiO2 Schottky interface and enhances the local electron density at the Co surface, confirmed by X-ray photoelectron spectroscopy results and density functional theory calculations. The Co/TiO2 Schottky catalyst displays superior HER activity with a turnover frequency of 0.052 s-1 and an exchange current density of 79 µA cm-2, which are about 4.3 and 4.0 times greater than that of pristine Co, respectively. Moreover, the Co/TiO2 Schottky catalyst displays excellent electrochemical durability for long-term operation in both alkaline solution and high saline solution. Theoretical calculations suggest that the Schottky junction plays an important role to optimize hydrogen adsorption free energy (ΔGH*) by tuning the electronic structure, which enhances the performance for HER of the Co/TiO2 Schottky catalyst. This study of modulating the electronic structure of the catalysts via the Schottky junction could provide valuable insights for designing and synthesizing low-cost, high-performance electrocatalysts.

Confinement Effects in Zeolite-Confined Noble Metals.

Confinement of noble nanometals in a zeolite matrix is a promising way to special types of catalysts that show significant advantages in size control, site adjustment, and nano-architecture design. The beauty of zeolite-confined noble metals lies in their unique confinement effects on a molecular scale, and thus enables spatially confined catalysis akin to enzyme catalysis. In this Minireview, the confined synthesis strategies of zeolite-confined noble metals will be briefly discussed, showing the processes, advantages, features, and mechanisms. The confined catalysis carried on zeolite-confined noble metals will be summarized, and great emphasis will be paid to the confinement effects involving size, encapsulation, recognition, and synergy. Great progress of atomic sites in the size effect, supercage stabilization in the encapsulation effect, site adsorption in the recognition effect, and cascade reaction in the synergy effect are highlighted. This Minireview is concluded with challenges and opportunities in terms of the synthesis of zeolite-confined noble metals and their applications to design multifunctional catalysts with high catalytic activity, selectivity, and stability.