Browse Articles

Decoupling Site‐Selective CO Poisoning From Hydrogen Oxidation Activity on Pt/C in PEMFCs

ABSTRACT Trace CO impurities in reformed hydrogen severely impair the performance of proton exchange membrane fuel cells (PEMFCs), yet the site‐specific mechanism of CO poisoning on hydrogen oxidation reaction (HOR) activity at Pt anodes under realistic operating conditions remains poorly understood. Herein, we reveal the site‐selective relationship between CO poisoning and HOR activity on Pt/C under practical fuel cell conditions by combining operando infrared spectroscopy with molecular probe experiments that quantitatively distinguish Pt surface sites during operation. Spectroscopic descriptors derived from the evolution of CO vibrational frequency and full width at half maximum (FWHM) reveal concentration‐dependent spatial distribution of adsorbed CO: at comparable coverages, low CO concentrations favor dispersed adsorption, whereas higher concentrations promote locally compact CO adlayers. Operando infrared measurements show that CO initially adsorbs on low‐coordinated Pt sites and progressively extends to high‐coordinated sites as coverage increases, while molecular probe experiments demonstrate that the initially poisoned low‐coordinated sites contribute negligibly to HOR activity, with high‐coordinated Pt sites dominating the HOR current. This work provides a molecular‐level understanding of site‐selective HOR activity on Pt/C and a mechanistically guided approach to improve anodic CO tolerance in PEMFCs.

Reply to Correspondence on “Confinement of Polyiodides by Dual‐Functional Tetrazine Cathodes in Zn‐I ₂ Batteries”

ABSTRACT In a correspondence related to our previous publication in Angewandte Chemie , Bianchi, Melguizo, et al. (B.M.) commented on the mechanistic interpretation and experimental framework underlying the interaction between 3,6‐bis(2‐morpholinoethyl)‐1,2,4,5‐tetrazine (BMT) and I 3 − in Zn‐I 2 batteries. In this reply, we show that the central findings and mechanistic interpretation of our work remain valid. First, B.M. should recognize the fundamental distinction between bulk solution chemistry and the reactions occurring at the electrochemical interface. It is critical to acknowledge that chemical reactions involving identical reactants may proceed through entirely different pathways under different physicochemical conditions—a principle that is particularly significant for electrochemistry. In Zn‐I 2 batteries, the cathodic electrochemical double layers (EDLs) constitute a highly polarized, spatially confined, and locally alkaline microenvironment. The 1:1 first‐step association constant reflects the rapid complexation kinetics of nonprotonated BMT toward I 3 − , highlighting its effectiveness in anchoring triiodide species at the cathode. Importantly, this value does not imply exclusive 1:1 complex formation, and it remains fully consistent with the 1:2 coordination stoichiometry revealed by the Job's plot analysis. Furthermore, well‐converged density functional theory calculations results are fully consistent with various experimental evidence, including in situ spectroscopic, in situ electrochemical measurements, and UV‐vis titration experiments in chloroform. Accordingly, the nonprotonated BMT‐I 3 − coordination mechanism proposed for Zn‐I 2 batteries is robust and internally consistent. In contrast, the protonated BMT‐I 3 − coordination studies reported by B.M. suffer from serious scientific/technical flaws, owing to interference from competing anions and the use of ill‐defined, strongly acidic solutions. Such experimental environments are fundamentally different from the cathodic EDL in Zn‐I 2 batteries. Nevertheless, to appropriately acknowledge prior contributions, multiple studies by B.M. are cited in both the Introduction and the Supporting Information. These citations fully comply with academic standards. This reply therefore clarifies the BMT‐I 3 − coordination mechanism in electrochemistry, reaffirms the validity of our conclusions, and underscores the decisive role of the EDL microenvironment in governing cathodic reactions.

Adaptive Brønsted Acidity From Heterolytic Dihydrogen Activation Enables Polyethylene Hydrogenolysis Over Pd‐Encapsulated Na‐Zeolites

ABSTRACT Converting polyethylene to liquid fuels requires Brønsted acidity, yet conventional acidic zeolites suffer from rapid coking and excessive gas formation. Despite Na‐exchanged zeolites are well‐known to resist coking in many cracking reactions, they are generally considered catalytically inert for polyethylene cracking due to absent acidity. Here, we show that encapsulated palladium nanoparticles in Na‐ZSM‐5 catalyze efficient polyethylene hydroconversion to C 5 ‐C 9 alkanes with minimal gas yield and negligible coke formation. Mechanistic studies reveal that dihydrogen undergoes heterolytic dissociation at the confined Pd‐zeolite interface, concurrently generating PdH hydrides and bridging hydroxyl groups that function as Brønsted acid sites. These dynamically created acid centers drive selective C─C bond scission via classical β‐scission pathways while circumventing the deleterious side reactions. This study establishes a general paradigm for adaptive catalysis wherein active sites are created in situ within otherwise non‐acidic frameworks, offering new strategies for selective bond activation.

p‐Block Antimony Single‐Atom Tuned Copper Sites for Boosting Electrocatalytic Semi‐Hydrogenation of 2‐methyl‐3‐butyn‐2‐ol

ABSTRACT Electrocatalytic semi‐hydrogenation of alkynes using water as the proton source at mild conditions is a highly attractive alternative to conventional methods, yet remains challenged by the competition of hydrogen evolution and over‐hydrogenation. Herein, we report an antimony‐copper single‐atom alloy nanowires (Sb 1 Cu NWs) as a robust and highly efficient electrocatalyst for selective electrosynthesis of 2‐methyl‐3‐buten‐2‐ol (MBE) via the semi‐hydrogenation reaction of 2‐methyl‐3‐butyn‐2‐ol (MBY) in H 2 O. The Sb 1 Cu NWs set a new record, achieving an MBE production rate of 1749.6 µmol cm −2 h −1 and a Faraday efficiency (FE) of 98%. Moreover, they maintain an FE above 80% across a broad potential window, outperforming previously reported catalysts. In situ electrochemical studies combined with theory calculations reveal that Sb single atoms can not only hamper the competing hydrogen evolution reaction by reconstructing a connected hydrogen‐bond network but also optimize the adsorption/desorption energetics of intermediates on Cu sites, thereby accelerating the conversion of MBY to MBE. Finally, a coupled system was designed to simultaneously realize the electrochemical semi‐hydrogenation of MBY and the oxidation of polyethylene terephthalate to produce MBE and formic acid, showing a lower potential at the same current density than that of coupled with anodic oxygen evolution, in an economical manner.

Self‐Assembling Nano‐Antimicrobial Oligopeptides With Dual Offense–Defense Functions for Synchronously Achieving High Activity and Biosafety

ABSTRACT Self‐assembling nano‐antimicrobial peptides (nano‐AMPs) hold significant promise for addressing bacterial resistance, yet the persistent activity–biocompatibility paradox remains a major scientific challenge. Here, we present an “integrated offense‒defense” strategy in which binding to mammalian cells is inhibited (defense) but bacterial membrane insertion is improved (offense), effectively decoupling antimicrobial potency from host cytotoxicity. We demonstrated that nano‐AMPs with moderate surface potentials (∼+20 mV) preferentially bind to bacteria and exhibit minimal interactions with mammalian cells because of the inherent charge disparity between bacterial and mammalian cell membranes. Experimental and theoretical analysis revealed that systematic sequence engineering resulted in peptide nanofibers with loose molecular packing and high exposure of hydrophobic residues. The optimized nano‐AMP exhibited potent antimicrobial activity (MIC of 5∼6 µM) and exceptional biosafety (therapeutic index TI = HC 10 / MIC > 30; selectivity index SI = IC 20 / MIC> 50). A murine skin wound infection model confirmed the antimicrobial efficacy of this peptide, which reduced the bacterial burden and promoted wound healing.

Hydroxylamine Hydrochloride as Bifunctional Reagent for Aminochlorination of Alkenes via Iron Catalysis

ABSTRACT While O ‐protected hydroxylamine derivatives have enabled various alkene amination reactions, their practical utility remains limited by poor atom economy and the requirement for multistep synthesis. Herein, we demonstrate that bulk chemical hydroxylamine hydrochloride serves as a bifunctional reagent for aminochlorination of alkenes via iron catalysis, producing water as the sole byproduct. An acidic medium is essential for the success of this transformation, operating by promoting the addition of the putative aminyl radical to alkene. This method exhibits a broad substrate scope and excellent functional group tolerance and is effective for the late‐stage functionalization of complex molecules. Notably, this reaction features a delayed chlorine transfer compared to the existing method. This mechanistic divergence grants exceptional selectivity in the transformation of substrates like 1,6‐dienes and camphene.

Hydrogels Under Superchaotropic Control: Polyoxometalate Stabilization and pH‐Responsive Crosslinking in Cellulose Ether Solutions

ABSTRACT Polymer‐polyoxometalate (POM) systems represent an emergent class of functional hybrid materials. However, the pH‐dependent stability of POMs limits their scope in water. We show here that the water‐mediated, so‐called superchaotropic binding of α‐Keggin POMs to a non‐ionic biopolymer, hydroxypropylcellulose (HPC), (i) selectively stabilizes superchaotropic POMs in water, and (ii) enables pH‐responsive HPC solutions and hydrogels. Raman and NMR spectroscopy revealed that binding to HPC protects the superchaotropic [PW 12 O 40 ] 3− and [SiW 12 O 40 ] 4− against hydrolysis, extending their stability from acidic to near‐neutral pH. In turn, POMs with higher charge, stronger hydration, and thus without the ability to bind to HPC, such as [H 2 W 12 O 40 ] 6− , [PW 11 O 39 ] 7− and [SiW 11 O 39 ] 8− , do not get stabilized. Cloud points, small‐angle neutron scattering, and rotational rheology showed that pH‐induced conversion from superchaotropic [PW 12 O 40 ] 3− to non‐superchaotropic [PW 11 O 39 ] 7− switches HPC from a bound, crosslinked to an unbound, non‐crosslinked state, enabling pH‐switchable viscosity and gel‐sol transitions. Superchaotropic stabilization and pH‐switching are proposed as general phenomena in superchaotropic POM/solute systems, highlighting the potential of superchaotropicity in aqueous soft materials.

A Low‐Temperature Solid Chemistry to Ru Clusterrene for Scalable Hydrogen Production

ABSTRACT Platinum‐group‐metal (PGM) nanomaterials are prominent in chemical and energy conversions. To date, their scalable manufacturing is confined by complex post‐processing or high‐temperature calcination (≥ 800°C), which are often required for conventional small‐sized nanoparticles. Herein, we have successfully developed a thermal buffer‐assisted low‐temperature (250°C) calcination strategy to create a sub‐nano Ru metallene called “Ru clusterrene” for anion exchange membrane water electrolysis (AEMWE). The rational use of NaCl is pivotal for successful synthesis, serving as a “buffer” to prevent thermal runaway. Consequently, the Ru clusterrene exhibits an ultra‐thin, fluid‐like structure that enables strong interaction with the substrate and ensures maximized active site exposure. Importantly, this strategy costs only US$39.42/g Ru , which is substantially lower than that of commercial Ru/C (Premetek, US$1407.50/g Ru ). The Ru clusterrene delivers an outstanding activity of 1.73 V@2 A cm ‒2 and 2.0 V@5.4 A cm ‒2 , as well as an unprecedented stability for 1000 h at 2 A cm ‒2 (80°C) and 3500 h at 1 A cm ‒2 (50°C). More significantly, it exhibits a high stack performance in AEMWE (3.6 V@1 A cm ‒2 and 2000 h@25 A), representing the most advanced level for AEMWE cathode catalyst.

Lithium‐Based Deep Eutectic in Spiro‐OMeTAD Enable Efficient and Stable Perovskite Solar Cells

ABSTRACT Doping of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and 4‐ tert ‐butylpyridine in 2,2',7,7'‐tetrakis( N,N ‐di‐p‐methoxyphenylamine)‐9,9'‐spirobifluorene (Spiro‐OMeTAD) is essential for achieving high efficiency in n‐i‐p type perovskite solar cells (PSCs). However, the migration of Li + and hygroscopic nature of LiTFSI reduce the long‐term stability of PSCs. In this work, we select 2,2’‐dipyridyl disulfide (DpyDS) to interact with Li + and it can form a liquid deep eutectic mixture with LiTFSI at room temperature. The liquid molecular film exhibits a dual function of suppressing Li + diffusion and repairing pores within the hole transport layer. In addition, DpyDS can facilitate the dissociation of TFSI − and enhance the hole mobility of Spiro‐OMeTAD, thereby promoting hole extraction and reducing non‐radiative recombination losses. The device doped with DpyDS achieves an unprecedented power conversion efficiency (PCE) of 26.53% (certified 26.37%). After 1800 h of maximum power point tracking, the unencapsulated device retains 90.5% of its initial PCE under the ISOS‐L‐1I protocol. This work validates a promising deep eutectic strategy with LiTFSI in Spiro‐OMeTAD, enhancing the PCE and long‐term stability of PSCs.

Deep Learning‐Enhanced DNAzyme‐Driven Rolling‐Circle Amplification Encoding for Multibacterial Detection

ABSTRACT Food‐borne outbreaks are frequently caused by multiple live pathogens that conventional methods cannot process simultaneously. We report a DNAzyme‐driven rolling‐circle amplification/molecular‐beacon encoding system (DRM‐ES) coupled with a smartphone‐based convolutional neural network (CNN) that simultaneously identifies and quantifies three live bacteria from 32 real‐world samples. Bacteria‐secreted proteins cleave bead‐immobilized DNAzymes, releasing primers that initiate RCA and generate long concatemers; each opens a spectrally distinct molecular beacon, producing blue, green, or red fluorescence captured in one smartphone image and decoded by a CNN trained on 2800 images. DRM‐ES achieves 10 1 –10 2 CFU/mL sensitivity for S. aureus , B. cocovenenans , and E. coli in food, clinical, and environmental samples; shows 100% positive and ≥95.2% negative agreement with culture; and correctly identifies 29/32 samples naturally contaminated with these three bacteria in a 32‐tube array. The platform offers culture‐comparable sensitivity and live‐cell specificity, providing a generalizable blueprint for large‐scale multiplex pathogen screening.

Author Response: From Diagnostic Concordance to Implementation-grade Lung Ultrasound in Critical Care

Ion‐Specific Freezing‐Induced NIR Phosphorescence: Interfacial Synergy Enables Imaging of “Invisible Ice”

ABSTRACT Icing threatens the safety of aviation, power‐transmission and wind‐energy systems, yet concealed or transparent ice remains difficult to detect. Here we report a freezing‐induced near‐infrared (NIR) phosphorescence (FIP) imaging strategy based on aryl‐substituted pyrrolo[3,2‐b]pyrrole probes PP4P‐X (X = F − , Br − , I − , NO 3 − , and SCN − ). Across the PP4P‐X series, freezing broadly amplifies the steady‐state emission, whereas a NIR phosphorescence band at 750 nm enables deep‐penetration, low‐background imaging with pronounced counterion dependence. The FIP turn‐on is strongest for PP4P‐F, followed by PP4P‐Br, switching from undetectable emission to intense phosphorescence. Mechanistic investigations reveal that specific adsorption of F − /Br − at the ice‐water interface induces dense aggregation at the freezing front, strengthening molecular interactions to promote intersystem crossing and suppress triplet non‐radiative decay. Leveraging this interfacial regulation, PP4P‐F enables high‐contrast, centimeter‐scale ice imaging in diverse frozen media, with a 152‐fold increase in signal‐to‐background ratio (SBR). In wind‐tunnel aircraft icing tests, FIP imaging accurately maps the onset, thickness evolution, and downstream propagation of ice along the wing leading edge and correlates with laser‐measured ice thickness. Overall, this work establishes a noncontact, in situ, and quantitative approach for “invisible ice” detection and provides a framework for NIR phosphorescent probes in frozen‐phase monitoring.

Practice Pattern of Critical Care UltraSonography in India (POCUS India): A Multicenter Cross-sectional Survey

Clinical Utility of Positive End-expiratory Pressure-incorporated PaO2/FiO2 Ratio in Prognosticating Mortality and Severity Reclassification in Acute Respiratory Distress Syndrome: A Systematic Review and Meta-analysis

High‐Capacity Adsorption and Thermal Destruction Adaptable to PFAS Chain Length via Crystal‐to‐Crystal Transformation of Zirconium–Organic Framework

ABSTRACT Per‐ and polyfluoroalkyl substances (PFAS) face the most stringent drinking water quality standards ever due to their potential toxicity and bioaccumulation potential. Their removal from water is commonly accomplished by adsorption, which is generally ineffective for short‐chain PFAS and unreliable for other homologues with diverse physicochemical properties. Here, we present a versatile platform based on zirconium‐based metal–organic frameworks (MOFs) to remove PFAS with different chain lengths via crystal‐to‐crystal transformation. The MOF [Zr 6 (μ 3 ‐O) 4 (μ 3 ‐OH) 4 PTA 3 (H 2 O) 4 ] n ( Zr‐PTA1 , PTA = 4,4′,4″,4′″‐(4,4′‐(1,4‐phenylene) bis (pyridine‐6,4,2‐triyl))tetrabenzoic acid) exhibits exceptional adsorption capacity for C8 PFAS (2945 ± 173 mg/g for perfluorooctanoic acid (PFOA) and 2322 ± 28 mg/g for perfluorooctane sulfonate (PFOS)), while its crystal‐to‐crystal transformation product [Zr 6 (μ 3 ‐O) 4 (μ 3 ‐OH) 4 PTA 2 (CH 3 COO) 4 ] n ( Zr‐PTA2 ) with abundant open metal sites (OMS) targets shorter‐chain C4 PFAS (375 ± 9 mg/g for perfluorobutanoic acid and 414 ± 41 mg/g for perfluorobutanesulfonic acid), surpassing all previously reported MOFs. Flow‐through column tests demonstrate rapid PFAS removal below 4 ng/L. This exceptional performance is due to distinct structural motifs—steric host–guest fit of Zr‐PTA1 for long‐chain PFAS versus OMS‐driven chemisorption of short‐chain PFAS by Zr‐PTA2 . Importantly, the framework facilitates subsequent thermal‐catalytic PFAS destruction, achieving 97 ± 5% PFOA degradation efficiency with 79 ± 0.3% fluoride recovery.

High-flow Nasal Cannula Oxygen vs Non-invasive Ventilation with Passive Humidification: Are We Comparing Like with Like?

Effectiveness of Nurse-led Interventions on Pain and Complications among Patients Admitted to Intensive Care Unit: A Quasi-experimental study

Inside Back Cover: A Dithio Vinylthio C ₂ Synthon Enabling Crystalline and Luminescent Sulfur‐Decorated Polymers (Angew. Chem. Int. Ed. 22/2026)

Author Response: Letter in Response to the Article: Network Meta-analysis of the Efficacy of Different Music Therapy Interventions for Delirium in Adult Intensive Care Unit Patients

Amorphous‐Phase Tailoring of TiO ₂ –ZrO ₂ Interfacial Linkages Regulates Radical Pathways for Highly Selective Photocatalytic Methane Oxidation

ABSTRACT Amorphous oxides offer unique short‐range order and coordination flexibility, yet their capacity to orchestrate interfacial radical chemistry and suppress over‐oxidation during photocatalytic methane to liquid conversion remains a critical frontier. Herein, we strategically construct TiO 2 –ZrO 2 architectures where the ZrO 2 phase is precisely tuned from amorphous (TiO 2 –ZrO 2 –A) to crystalline (TiO 2 –ZrO 2 –A800) to elucidate the governance of structural disorder over aerobic CH 4 functionalization. Multimodal characterizations—including x–ray absorption near‐edge structure (XANES)/extended x‐ray absorption fine structure (EXAFS), AC‐HRTEM, transient electron paramagnetic resonance (EPR), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT), reveal that the amorphous ZrO 2 phase enriches surface oxygen vacancies relative to its crystalline counterpart and establishes robust Ti–O–Zr interfacial linkages. This configuration enhances charge separation and supports higher effective steady‐state hole availability for efficient C–H bond activation while effectively tempering the flux of water‐derived reactive oxygen species. At room temperature TiO 2 –ZrO 2 –A achieves an exceptional liquid oxygenate selectivity of up to 98.2%, remarkably outperforming its crystalline analogue by resisting deep oxidation to CO 2 . Kinetic analyses reveal the rapid formation of *CH 3 and *CH 3 O intermediates, consistent with faster intermediate turnover and reduced overoxidation on the amorphous interface, consistent with DFT‐calculated barriers that favor methane activation over non‐selective reactive oxygen species (ROS) generation. These findings identify amorphous‐phase engineering as a kinetic valve for tuning pathways and selectivity in photocatalytic C–H transformations.