Highly selective synthesis of surface FeIV=O with nanoscale zero-valent iron and chlorite for efficient oxygen transfer reactions.

High-valent iron-oxo species (FeIV=O) has been a long-sought-after oxygen transfer reagent in biological and catalytic chemistry but suffers from a giant challenge in its gentle and selective synthesis. Herein, we propose a new strategy to synthesize surface FeIV=O (≡FeIV=O) on nanoscale zero-valent iron (nZVI) using chlorite (ClO2-) as the oxidant, which possesses an impressive ≡FeIV=O selectivity of 99%. ≡FeIV=O can be energetically formed from the ferrous (FeII) sites on nZVI through heterolytic Cl-O bond dissociation of ClO2- via a synergistic effect between electron-donating surface ≡FeII and proximal electron-withdrawing H2O, where H2O serves as a hydrogen-bond donor to the terminal O atom of the adsorbed ClO2- thereby prompting the polarization and cleavage of Cl-O bond for the oxidation of ≡FeII toward the final formation of ≡FeIV=O. With methyl phenyl sulfoxide (PMS16O) as the probe molecule, the isotopic labeling experiment manifests an exclusive 18O transfer from Cl18O2- to PMS16O18O mediated by ≡FeIV=18O. We then showcase the versatility of ≡FeIV=O as the oxygen transfer reagent in activating the C-H bond of methane for methanol production and facilitating selective triphenylphosphine oxide synthesis with triphenylphosphine. We believe that this new ≡FeIV=O synthesis strategy possesses great potential to drive oxygen transfer for efficient high-value-added chemical synthesis.

Homogeneous Vacancies-Enhanced Orbital Hybridization for Selective and Efficient CO2-to-CO Electrocatalysis.

Crafting vacancies offers an efficient route to upgrade the selectivity and productivity of nanomaterials for CO2 electroreduction. However, defective nanoelectrocatalysts bear catalytically active vacancies mostly on their surface, with the rest of the interior atoms adiaphorous for CO2-to-product conversion. Herein, taking nanosilver as a prototype, we arouse the catalytic ability of internal atoms by creating homogeneous vacancies realized via electrochemical reconstruction of silver halides. The homogeneous vacancies-rich nanosilver, compared to the surface vacancies-dominated counterpart, features a more positive d-band center to trigger an intensified hybridization of the Ag_d orbital with the C_P orbital of the *COOH intermediate, leading to an accelerated CO2-to-CO transformation. These structural and electronic merits allow a large-area (9 cm-2) electrode to generate nearly pure CO with a CO/H2 Faradaic efficiency ratio of 6932 at an applied current of 7.5 A. These findings highlight the potential of designing new-type defects in realizing the industrialization of electrocatalytic CO2 reduction.

Photochemical Acceleration of Ammonia Production by Pt1-Ptn-TiN Reduction and N2 Activation.

Stable metal nitrides (MN) are promising materials to fit the future "green" ammonia-hydrogen nexus. Either through catalysis or chemical looping, the reductive hydrogenation of MN to MN1-x is a necessary step to generate ammonia. However, encumbered by the formation of kinetically stable M-NH1─3 surface species, this reduction step remains challenging under mild conditions. Herein, we discovered that deleterious Ti-NH1─3 accumulation on TiN can be circumvented photochemically with supported single atoms and clusters of platinum (Pt1-Ptn) under N2-H2 conditions. The photochemistry of TiN selectively promoted Ti-NH formation, while Pt1-Ptn effectively transformed any formed Ti-NH into free ammonia. The generated ammonia was found to originate mainly from TiN reduction with a minor contribution from N2 activation. The knowledge accrued from this fundamental study could serve as a springboard for the development of MN materials for more efficient ammonia production to potentially disrupt the century-old fossil-powered Haber-Bosch process.

Triangle Cl-Ag1 -Cl Sites for Superior Photocatalytic Molecular Oxygen Activation and NO Oxidation of BiOCl.

BiOCl photocatalysis shows great promise for molecular oxygen activation and NO oxidation, but its selective transformation of NO to immobilized nitrate without toxic NO2 emission is still a great challenge, because of uncontrollable reaction intermediates and pathways. In this study, we demonstrate that the introduction of triangle Cl-Ag1 -Cl sites on a Cl-terminated, (001) facet-exposed BiOCl can selectively promote one-electron activation of reactant molecular oxygen to intermediate superoxide radicals (⋅O2 - ), and also shift the adsorption configuration of product NO3 - from the weak monodentate binding mode to a strong bidentate mode to avoid unfavorable photolysis. By simultaneously tuning intermediates and products, the Cl-Ag1 -Cl-landen BiOCl achieved >90 % NO conversion to favorable NO3 - of high selectivity (>97 %) in 10 min under visible light, with the undesired NO2 concentration below 20 ppb. Both the activity and the selectivity of Cl-Ag1 -Cl sites surpass those of BiOCl surface sites (38 % NO conversion, 67 % NO3 - selectivity) or control O-Ag1 -O sites on a benchmark photocatalyst P25 (67 % NO conversion and 87 % NO3 - selectivity). This study develops new single-atom sites for the performance enhancement of semiconductor photocatalysts, and also provides a facile pathway to manipulate the reactive oxygen species production for efficient pollutant removal.

Visible Light-Driven Conversion of Carbon-Sequestrated Seawater into Stoichiometric CO and HClO with Nitrogen-Doped BiOCl Atomic Layers.

Seawater is one of the most important CO2 sequestration media for delivering value-added chemicals/fuels and active chlorine; however, this scenario is plagued by sluggish reaction rates and poor product selectivity. Herein, we first report the synthesis of nitrogen-doped BiOCl atomic layers to directly split carbon-sequestrated natural seawater (Yellow Sea, China) into stoichiometric CO (92.8 µmol h-1 ) and HClO (83.2 µmol h-1 ) under visible light with selectivities greater than 90 %. Photoelectrons enriched on the exposed BiOCl{001} facet kinetically facilitate CO2 -to-CO reduction via surface-doped nitrogen bearing Lewis basicity. Photoholes, mainly located on the lateral facets of van der Waals gaps, promote the selective oxidation of Cl- into HClO. Sequestrated CO2 also maintains the pH of seawater at around 4.2 to prevent the alkaline earth cations from precipitating. The produced HClO can effectively kill typical bacteria in the ballast water of ocean-going cargo ships, offering a green and safe way for onsite sterilization.

Solar Hydrocarbons: Single-Step, Atmospheric-Pressure Synthesis of C2 -C4 Alkanes and Alkenes from CO2.

Cobalt ferrite (CoFe2 O4 ) spinel has been found to produce C2 -C4 hydrocarbons in a single-step, ambient-pressure, photocatalytic hydrogenation of CO2 with a rate of 1.1 mmol g-1 h-1 , selectivity of 29.8 % and conversion yield of 12.9 %. On stream the CoFe2 O4 reconstructs to a CoFe-CoFe2 O4 alloy-spinel nanocomposite which facilitates the light-assisted transformation of CO2 to CO and hydrogenation of the CO to C2 -C4 hydrocarbons. Promising results obtained from a laboratory demonstrator bode well for the development of a solar hydrocarbon pilot refinery.

In Situ Visualization on Surface Oxidative Corrosion with Free Radicals: Black Phosphorus Nanoflake as an Example.

Free radicals exert a significant impact on the fate of redox-active substances and play a crucial role in the surface corrosion of solid in environment. Dynamic visualization on the response of the surface to the free radicals at nanoscale is essential to explore the mechanism. Environmental transmission electron microscopy will be a powerful tool for dynamic changes of the interface redox process of solid surface with electron beams induced free radicals, to simulate the redox process of a solid in the environment. Black phosphorus (BP), an environment-sensitive material, is selected as an example to visualize the degradation pathways with environmental transmission electron microscopy. The distribution of the corrosion initiation points, formation and growth of corrosion areas, and the eventual splintering and disappearance of BP nanoflakes are recorded vividly. In situ results are substantiated by the ex situ experiments and density functional theory (DFT) calculations. Results show that degradation originates at the edges and defect structures when the humidity reaches high enough. The microscopic structural oxidative etching of solid surface with radicals in natural light is simulated with radicals produced by electron beam irradiation on suspending medium O2 and H2O for the first time. This method will offer unprecedented details and valuable insights into the mechanism involved in the oxidative etching with natural light.

Oxygen and Chlorine Dual Vacancies Enable Photocatalytic O2 Dissociation into Monatomic Reactive Oxygen on BiOCl for Refractory Aromatic Pollutant Removal.

Room-temperature molecular oxygen (O2) dissociation is challenging toward chemical reactions due to its triplet ground-state and spin-forbidden characteristic. Herein, we demonstrate that BiOCl of oxygen and chlorine dual vacancies can photocatalytically dissociate O2 into monatomic reactive oxygen (•O-) for the ring opening of aromatic refractory pollutants toward deep oxidation. The electron-rich and geometry-flexible dual vacancies of oxygen and chlorine remarkably lengthen the O-O bond of adsorbed O2 from 1.21 to 2.74 Å, resulting in the rapid O2 dissociation and the subsequent •O- formation. During the photocatalytic degradation of sulfamethazine, the in situ-formed •O- plays an indispensable role in breaking the critical intermediate of pyrimidine containing a stubborn aromatic heterocyclic ring, thus facilitating the overall mineralization. More importantly, BiOCl of oxygen and chlorine dual vacancies is also superior to its monovacancy counterparts on the degradation of other refractory pollutants containing conjugated six-membered rings, including p-chlorophenol, p-chloronitrobenzene, p-hydroxybenzoic acid, and p-nitrobenzoic acid. This study sheds light on the importance of sophisticated defects for regulating the O2 activation manner and deliveries a novel O2 activation approach for environmental remediation with solar energy.

Near-Perfect Absorbing Copper Metamaterial for Solar Fuel Generation.

Metamaterials are a new class of artificial materials that can achieve electromagnetic properties that do not occur naturally, and as such they can also be a new class of photocatalytic structures. We show that metal-based catalysts can achieve electromagnetic field amplification and broadband absorption by decoupling optical properties from the material composition as exemplified with a ZnO/Cu metamaterial surface comprising periodically arranged nanocubes. Through refractive index engineering close to the index of air, the metamaterial exhibits near-perfect 98% absorption. The combination of plasmonics and broadband absorption elevates the weak electric field intensities across the nonplasmonic absorption range. This feedback between optical excitation and plasmonic excitation dramatically enhances light-to-dark catalytic rates by up to a factor of 181 times, compared to a 3 times photoenhancement of ZnO/Cu nanoparticles or films, and with angular invariance. These results show that metamaterial catalysts can act as a singular light harvesting device that substantially enhances photocatalysis of important reactions.

Enhanced CO2 Photocatalysis by Indium Oxide Hydroxide Supported on TiN@TiO2 Nanotubes.

Herein is developed a ternary heterostructured catalyst, based on a periodic array of 1D TiN nanotubes, with a TiO2 nanoparticulate intermediate layer and a In2O3-x(OH)y nanoparticulate shell for improved performance in the photocatalytic reverse water gas shift reaction. It is demonstrated that the ordering of the three components in the heterostructure sensitively determine its activity in CO2 photocatalysis. Specifically, TiN nanotubes not only provide a photothermal driving force for the photocatalytic reaction, owing to their strong optical absorption properties, but they also serve as a crucial scaffold for minimizing the required quantity of In2O3-x(OH)y nanoparticles, leading to an enhanced CO production rate. Simultaneously, the TiO2 nanoparticle layer supplies photogenerated electrons and holes that are transferred to active sites on In2O3-x(OH)y nanoparticles and participate in the reactions occurring at the catalyst surface.

Solar Urea: Towards a Sustainable Fertilizer Industry.

Urea, an agricultural fertilizer, nourishes humanity. The century-old Bosch-Meiser process provides the world's urea. It is multi-step, consumes enormous amounts of non-renewable energy, and has a large CO2 footprint. Thus, developing an eco-friendly synthesis for urea is a priority. Herein we report a single-step Pd/LTA-3A catalyzed synthesis of urea from CO2 and NH3 under ambient conditions powered solely by solar energy. Pd nanoparticles serve the dual function of catalyzing the dissociation of NH3 and providing the photothermal driving force for urea formation, while the absorption capacity of LTA-3A removes by-product H2 O to shift the equilibrium towards urea production. The solar urea conversion rate from NH3 and CO2 is 87 µmol g-1 h-1 . This advance represents a first step towards the use of solar energy in urea production. It provides insights into green fertilizer production, and inspires the vision of sustainable, modular plants for distributed production of urea on farms.

Kirkendall Effect Boosts Phosphorylated nZVI for Efficient Heavy Metal Wastewater Treatment.

Removal of non-biodegradable heavy metals has been the top priority in wastewater treatment and the development of green technologies remains a significant challenge. We demonstrate that phosphorylated nanoscale zero-valent iron (nZVI) is promising for removal of heavy metals (NiII , CuII , CrVI , HgII ) via a boosted Kirkendall effect. Phosphorylation confines tensile hoop stress on the nZVI particles and "breaks" the structurally dense spherical nZVI to produce numerous radial nanocracks. Exemplified by NiII removal, the radial nanocracks favor the facile inward diffusion of NiII and the rapid outward transport of electrons and ferrous ions through the oxide shell for surface (NiII /electron) and boundary (NiII /Fe0 ) galvanic exchange. Accompanied by a pronounced hollowing phenomenon, phosphorylated nZVI can instantly reduce and immobilize NiII throughout the oxide shell with a high capacity (258 mg Ni g-1 Fe). For real electroplating factory wastewater treatment, this novel nZVI performs simultaneous NiII and CuII removal, producing effluent of stable quality that meets local discharge regulations.

Hydrogen Spillover to Oxygen Vacancy of TiO2-xHy/Fe: Breaking the Scaling Relationship of Ammonia Synthesis.

Optimizing kinetic barriers of ammonia synthesis to reduce the energy intensity has recently attracted significant research interest. The motivation for the research is to discover means by which activation barriers of N2 dissociation and NHz (z = 1-2, surface intermediates) destabilization can be reduced simultaneously, that is, breaking the "scaling relationship". However, by far only a single success has been reported in 2016 based on the discovery of a strong-weak N-bonding pair: transition metals (nitrides)-LiH. Described herein is a second example that is counterintuitively founded upon a strong-strong N-bonding pair unveiled in a bifunctional nanoscale catalyst TiO2-xHy/Fe (where 0.02 ≤ x ≤ 0.03 and 0 < y < 0.03), in which hydrogen spillover (H) from Fe to cascade oxygen vacancies (OV-OV) results in the trapped form of OV-H on the TiO2-xHy component. The Fe component thus enables facile activation of N2, while the OV-H in TiO2-xHy hydrogenates the N or NHz to NH3 easily.

Efficient Ammonia Electrosynthesis from Nitrate on Strained Ruthenium Nanoclusters.

The limitations of the Haber-Bosch reaction, particularly high-temperature operation, have ignited new interests in low-temperature ammonia-synthesis scenarios. Ambient N2 electroreduction is a compelling alternative but is impeded by a low ammonia production rate (mostly <10 mmol gcat-1 h-1), a small partial current density (<1 mA cm-2), and a high-selectivity hydrogen-evolving side reaction. Herein, we report that room-temperature nitrate electroreduction catalyzed by strained ruthenium nanoclusters generates ammonia at a higher rate (5.56 mol gcat-1 h-1) than the Haber-Bosch process. The primary contributor to such performance is hydrogen radicals, which are generated by suppressing hydrogen-hydrogen dimerization during water splitting enabled by the tensile lattice strains. The radicals expedite nitrate-to-ammonia conversion by hydrogenating intermediates of the rate-limiting steps at lower kinetic barriers. The strained nanostructures can maintain nearly 100% ammonia-evolving selectivity at >120 mA cm-2 current densities for 100 h due to the robust subsurface Ru-O coordination. These findings highlight the potential of nitrate electroreduction in real-world, low-temperature ammonia synthesis.

Plasmonic Titanium Nitride Facilitates Indium Oxide CO2 Photocatalysis.

Nanoscale titanium nitride TiN is a metallic material that can effectively harvest sunlight over a broad spectral range and produce high local temperatures via the photothermal effect. Nanoscale indium oxide-hydroxide, In2 O3- x (OH)y , is a semiconducting material capable of photocatalyzing the hydrogenation of gaseous CO2 ; however, its wide electronic bandgap limits its absorption of photons to the ultraviolet region of the solar spectrum. Herein, the benefits of both nanomaterials in a ternary heterostructure: TiN@TiO2 @In2 O3- x (OH)y are combined. This heterostructured material synergistically couples the metallic TiN and semiconducting In2 O3- x (OH)y phases via an interfacial semiconducting TiO2 layer, allowing it to drive the light-assisted reverse water gas shift reaction at a conversion rate greatly surpassing that of its individual components or any binary combinations thereof.

Oxygen Vacancies Promoted the Selective Photocatalytic Removal of NO with Blue TiO2 via Simultaneous Molecular Oxygen Activation and Photogenerated Hole Annihilation.

Semiconductor photocatalytic technology has great potential for the removal of dilute gaseous NO in indoor and outdoor atmospheres but suffers from unsatisfactory NO-removal selectivity due to undesirable NO2 byproduct generation. In this study, we demonstrate that the 99% selectivity of photocatalytic NO oxidation toward nitrate can be achieved over blue TiO2 bearing oxygen vacancies (OVs) under visible-light irradiation. First-principles density functional theory calculation and experimental results suggested that the OVs of blue TiO2 with localized electrons could facilitate the molecular oxygen activation through single-electron pathways to generate ·O2- and simultaneously promote the photogenerated hole annihilation. The generated ·O2- directly converted NO to nitrate, while the hole annihilation inhibited the side-reaction between holes and NO to avoid toxic NO2 byproduct formation, resulting in the highly selective removal of NO. This study reveals the dual functions of OVs in defective photocatalysts and also provides fundamental guidance for the selective purification of NO with photocatalytic technology.

Understanding the role of transition metal single-atom electronic structure in oxysulfur radical-mediated oxidative degradation.

The ubiquity of refractory organic matter in aquatic environments necessitates innovative removal strategies. Sulfate radical-based advanced oxidation has emerged as an attractive solution, offering high selectivity, enduring efficacy, and anti-interference ability. Among many technologies, sulfite activation, leveraging its cost-effectiveness and lower toxicity compared to conventional persulfates, stands out. Yet, the activation process often relies on transition metals, suffering from low atom utilization. Here we introduce a series of single-atom catalysts (SACs) employing transition metals on g-C3N4 substrates, effectively activating sulfite for acetaminophen degradation. We highlight the superior performance of Fe/CN, which demonstrates a degradation rate constant significantly surpassing those of Ni/CN and Cu/CN. Our investigation into the electronic and spin polarization characteristics of these catalysts reveals their critical role in catalytic efficiency, with oxysulfur radical-mediated reactions predominating. Notably, under visible light, the catalytic activity is enhanced, attributed to an increased generation of oxysulfur radicals and a strengthened electron donation-back donation dynamic. The proximity of Fe/CN's d-band center to the Fermi level, alongside its high spin polarization, is shown to improve sulfite adsorption and reduce the HOMO-LUMO gap, thereby accelerating photo-assisted sulfite activation. This work advances the understanding of SACs in environmental applications and lays the groundwork for future water treatment technologies.

Rheumatoid arthritis and the risk of chronic kidney diseases: a Mendelian randomization study.

Background: The extra-articular lesions of rheumatoid arthritis (RA) are reported to involve multiple organs and systems throughout the body, including the heart, kidneys, liver, and lungs. This study assessed the potential causal relationship between RA and the risk of chronic kidney diseases (CKDs) using the Mendelian randomization (MR) analysis. Method: Independent genetic instruments related to RA and CKD or CKD subtypes at the genome-wide significant level were chosen from the publicly shared summary-level data of genome-wide association studies (GWAS). Then, we obtained some single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs), which are associated with RA in individuals of European origin, and had genome-wide statistical significance (p5 × 10-8). The inverse-variance weighted (IVW) method was the main analysis method in MR analysis. The other methods, such as weighted median, MR-Egger, simple mode, and weighted mode were used as supplementary sensitivity analyses. Furthermore, the levels of pleiotropy and heterogeneity were assessed using Cochran's Q test and leave-one-out analysis. Furthermore, the relevant datasets were obtained from the Open GWAS database. Results: Using the IVW method, the main method in MR analysis, the results showed that genetically determined RA was associated with higher risks of CKD [odds ratio (OR): 1.22, 95% confidence interval (CI) 1.13-1.31; p < 0.001], glomerulonephritis (OR: 1.23, 95% CI 1.15-1.31; p < 0.000), amyloidosis (OR = 1.43, 95% CI 1.10-1.88, p < 0.001), and renal failure (OR = 1.18, 95% CI 1.00-1.38, p < 0.001). Then, using multiple MR methods, it was confirmed that the associations persisted in sensitivity analyses, and no pleiotropy was detected. Conclusion: The findings revealed a causal relationship between RA and CKD, including glomerulonephritis, amyloidosis, and renal failure. Therefore, RA patients should pay more attention to monitoring their kidney function, thus providing the opportunity for earlier intervention and lower the risk of progression to CKDs.

VSIG4 Silencing Inhibits Glioblastoma Growth by Regulating the JAK2/STAT3 Pathway.

Background: Glioblastoma (GBM) is the most common malignant primary brain tumour in adults. VSIG4 has been identified to be associated with GBM. We aimed to determine the downstream regulatory mechanisms of VSIG4 in GBM. Methods: Differential expression of VSIG4 was analysed using GEPIA. The expression of VSIG4 was assessed by RT-qPCR and its downstream genes were screened by transcriptome sequencing. The expression of pyroptosis-related proteins and the JAK2/STAT3 pathway was measured by Western blotting. GBM cell viability, migration, and invasion were detected using CCK-8, scratch, and Transwell assays. The levels of pyroptosis-related factors were measured using ELISA. The effect of VSIG4 on GBM tumour growth in vivo was explored by constructing a xenograft tumour model. Results: VSIG4 expression was upregulated in GBM. Functionally, silencing of VSIG4 inhibited proliferation, invasion, and migration of U251 and LN229 cells, and promoted pyroptosis. Mechanically, transcriptome sequencing revealed that the JAK2/STAT3 pathway might be a downstream regulator of VSIG4. Further studies proved that silencing of VSIG4 enhanced the expression of p-JAK2 and p-STAT3, and the JAK2/STAT3 pathway inhibitor relieved the suppression of VSIG4 silencing on GBM cell viability, invasion, and migration. Furthermore, in vivo experiments further validated that knockdown of VSIG4 inhibited the growth of GBM tumors. Conclusion: In GBM, silencing VSIG4 promoted pyroptosis and inhibited tumor progression by regulating the JAK2/STAT3 signaling pathway.

ZnO Nanorod-Immobilized Pt Single-Atoms as an Ultrasensitive Sensor for Triethylamine Detection.

Triethylamine (TEA) is a flammable and highly toxic gas, and the fast, accurate, and sensitive detection of gas TEA remains greatly challenging. Herein, we report a ZnO nanorod anchored with a single-atom Pt catalyst (Pt1/ZnO) as a gas sensor for TEA detection. The sensor shows high selectivity and high response to gas TEA with a response value of 4170 at 200 °C, which is 92 times higher than that of pure ZnO. Moreover, the Pt1/ZnO sensor has very short response and recovery times of only 34 and 76 s, respectively, and also has a high response to ppb-level TEA gas (100 ppb-21.6). The gas-sensing enhancement mechanism of the Pt1/ZnO sensor to gas TEA was systematically investigated using band structure analysis, in situ diffuse reflectance infrared Fourier transformation spectroscopy, and density functional theory calculations. The results show that the oxygen vacancies on Pt1/ZnO can effectively activate the adsorbed oxygen. Moreover, chemical bonds can be formed between Pt single atoms and N atoms in TEA to achieve effective adsorption and activation of TEA molecules, facilitating the reaction between TEA and the adsorbed oxygen on Pt1/ZnO, and thereby obtaining high gas-sensing performance. This work highlights the crucial role of Pt single-atom in improving the sensing performance for gas TEA detection, paving the way for developing more advanced gas sensors.