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The selective hydrogenation of carbon dioxide (CO 2 ) to value-added chemicals, e.g., methanol, using green hydrogen retrieved from renewable resources is a promising approach for CO 2 emission reduction and carbon resource utilization. However, this process suffers from the competing side reaction of reverse water-gas shift (RWGS) and methanol decomposition, which often leads to a strong conversion-selectivity trade-off and thus a poor methanol yield. Here, we report that InO x coating of PdCu bimetallic nanoparticles (NPs) to construct intimate InO x /Cu and InO x /PdIn dual interfaces enables the break of conversion-selectivity trade-off by achieving ∼80% methanol selectivity at ∼20% CO 2 conversion close to the thermodynamic limit, far superior to that of conventional metal catalysts with a single active metal/oxide interface. Comprehensive microscopic and spectroscopic characterization revealed that the InO x /PdIn interface favors the activation of CO 2 to formate, while the adjacent InO x /Cu interface readily converts formate intermediates to methoxy species in tandem, which thus cooperatively boosts methanol production. These findings of dual-interface synergies via oxide coating of bimetallic NPs open a new avenue to the design of active and selective catalysts for advanced catalysis.

Propane dehydrogenation (PDH), an atom-economic reaction to produce high-value-added propylene and hydrogen with high efficiency, has recently attracted extensive attention. The severe deactivation of Pt-based catalysts through sintering and coking remains a major challenge in this high-temperature reaction. The introduction of Sn as a promoter has been widely applied to improve the stability and selectivity of the catalysts. However, the selectivity and stability of PtSn catalysts have been found to vary considerably with synthesis methods, and the role of Sn is still far from fully understanding. To gain in-depth insights into this issue, we synthesized a series of PtSn/SiO 2 and SnPt/SiO 2 catalysts by varying the deposition sequence and Pt:Sn ratios using atomic layer deposition with precise control. We found that PtSn/SiO 2 catalysts fabricated by the deposition of SnO x first and then Pt, exhibited much better propylene selectivity and stability than the SnPt/SiO 2 catalysts synthesized the other way around. We demonstrate that the presence of Sn species at the Pt-SiO 2 interface is of essential importance for not only the stabilization of PtSn clusters against sintering under reaction conditions but also the promotion of charge transfers to Pt for high selectivity. Besides the above, the precise regulation of the Sn content is also pivotal for high performance, and the excess amount of Sn might generate additional acidic sites, which could decrease the propylene selectivity and lead to heavy coke formation. These findings provide deep insight into the design of highly selective and stable PDH catalysts., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Co-published by University of Science and Technology of China and American Chemical Society.)

Reactive metal-support interactions (RMSIs) induce the formation of bimetallic alloys and offer an effective way to tune the electronic and geometric properties of metal sites for advanced catalysis. However, RMSIs often require high-temperature reductions (>500 °C), which significantly limits the tuning of bimetallic compositional varieties. Here, we report that an atomically thick Ga 2 O 3 coating of Pd nanoparticles enables the initiation of RMSIs at a much lower temperature of ∼250 °C. State-of-the-art microscopic and in situ spectroscopic studies disclose that low-temperature RMSIs initiate the formation of rarely reported Ga-rich PdGa alloy phases, distinct from the Pd 2 Ga phase formed in traditional Pd/Ga 2 O 3 catalysts after high-temperature reduction. In the CO 2 hydrogenation reaction, the Ga-rich alloy phases impressively boost the formation of methanol and dimethyl ether ∼5 times higher than that of Pd/Ga 2 O 3 . In situ infrared spectroscopy reveals that the Ga-rich phases greatly favor formate formation as well as its subsequent hydrogenation, thus leading to high productivity.

Extracellular vesicle (EV) cargos with regular fluctuations hold the potential for providing chemical predictors toward clinical diagnosis and prognosis. A plasma sample is one of the most important sources of circulating EVs, yet the technical barrier and cost consumption in plasma-EV isolation still limit its application in disease diagnosis and biomarker discovery. Here, we introduced an easy-to-use strategy that allows selectively purifying small EVs (sEVs) from human plasma and detecting their metabolic alternations. Fe 3 O 4 @TiO 2 microbeads with a rough island-shaped surface have proven the capability of performing efficient and reversible sEV capture owing to the phospholipid affinity, enhanced binding sites, and size-exclusion-like effect of the rough TiO 2 shell. The proposed system can also shorten the separation procedure from hours to 20 min when compared with the ultracentrifugation method and yield approximately 10 8 sEV particles from 100 μL of plasma. Metabolome variations of sEVs among progressive diabetic retinopathy subjects were finally studied, observing a cluster of metabolites with elevated levels and suggesting potential roles of these sEV chemicals in diabetic retinopathy onset and progression. Such a scalable and flexible EV capture system can be seen as an effective analytical tool for facilitating plasma-based liquid biopsies.

Phosphor-containing white light-emitting diodes (LEDs) with low color-correlated temperatures (CCTs) and high color rendering indexes (CRIs) are highly desirable for energy-efficient and environmentally friendly solid-state light sources. Here, we report a new and efficient blue light-excited, green-emitting Ce 3+ -activated CaY 2 ZrScAl 3 O 12 phosphor, which underpins the fabrication of high-color quality and full-visible-spectrum warm-white LED devices with ultrahigh CRI values (Ra > 96 and R9 > 96). A family of CaY 2 ZrScAl 3 O 12 :Ce 3+ phosphors with different Ce 3+ dopant concentrations were prepared by high-temperature solid-state synthesis. X-ray diffraction and corresponding Rietveld refinement reveal a garnet structure with an Ia 3̅ d space group and crystallographic parameters a = b = c = 12.39645(8) Å, α = β = γ = 90°, and V = 1904.99(4) Å 3 . Luminescence properties were studied in detail as a function of Ce 3+ with the optimal concentration 1% mol. Impressively, CaY 2 ZrScAl 3 O 12 :1%Ce 3+ exhibits a broad excitation band from 370 to 500 nm, peaking at ∼421 nm, which is well matched with emission from commercial blue LED chips. Under 421 nm excitation, the CaY 2 ZrScAl 3 O 12 :1%Ce 3+ phosphor produces dazzling green light in a wide emission band from 435 to 750 nm (emission peak: 514 nm; full width at half-maximum: 113 nm), with a high internal quantum efficiency of 63.1% and good resistance to thermal quenching (activation energy of 0.28 eV). A white LED device combining a 450 nm blue LED chip with CaY 2 ZrScAl 3 O 12 :1%Ce 3+ green phosphor and commercial CaAlSiN 3 :Eu 2+ red phosphor as color converters demonstrates bright warm-white light with excellent CIE color coordinates of (0.3938, 0.3819), low CCT of 3696 K, high CRI (Ra = 96.9, R9 = 98.2), and high luminous efficacy of 45.04 lm W -1 under a 20 mA driving current. New green phosphors enable the design and implementation of efficient luminescent materials for healthy solid-state lighting.

Controlling the chemical environments of the active metal atom including both coordination number (CN) and local composition (LC) is vital to achieve active and stable single-atom catalysts (SACs), but remains challenging. Here we synthesized a series of supported Pt 1 SACs by depositing Pt atoms onto the pretuned anchoring sites on nitrogen-doped carbon using atomic layer deposition. In hydrogenation of para -chloronitrobenzene, the Pt 1 SAC with a higher CN about four but less pyridinic nitrogen (N pyri ) content exhibits a remarkably high activity along with superior recyclability compared to those with lower CNs and more N pyri . Theoretical calculations reveal that the four-coordinated Pt 1 atoms with about 1 eV lower formation energy are more resistant to agglomerations than the three-coordinated ones. Composition-wise decrease of the Pt-N pyri bond upshifts gradually the Pt-5 d center, and minimal one Pt-N pyri bond features a high-lying Pt-5 d state that largely facilitates H 2 dissociation, boosting hydrogenation activity remarkably.

Recent advances in chemical synthesis have made it possible to produce gold and silver nanowires that are free of large-scale crystalline defects and surface roughness. Surface plasmons can propagate along the wires, allowing them to serve as optical waveguides with cross sections much smaller than the optical wavelength. Gold nanowires provide improved chemical stability as compared to silver nanowires, but at the cost of higher losses for the propagating plasmons. In order to characterize this trade-off, we measured the propagation length and group velocity of plasmons in both gold and silver nanowires. Propagation lengths are measured by fluorescence imaging of the plasmonic near fields. Group velocities are deduced from the spacing of fringes in the spectrum of coherent light transmitted by the wires. In contrast to previous work, we interpret these fringes as arising from a far-field interference effect. The measured propagation characteristics agree with numerical simulations, indicating that propagation in these wires is dominated by the material properties of the metals, with additional losses due to scattering from roughness or grain boundaries providing at most a minor contribution. The propagation lengths and group velocities can also be described by a simple analytical model that considers only the lowest-order waveguide mode in a solid metal cylinder, showing that this single mode dominates in real nanowires. Comparison between experiments and theory indicates that widely used tabulated values for dielectric functions provide a good description of plasmons in gold nanowires but significantly overestimate plasmon losses in silver nanowires., (© 2011 American Chemical Society)

Three-dimensional finite-difference time-domain simulations were performed to explore the excitation of surface plasmon resonances in long silver (Ag) nanowires. In particular, we show that it is possible to generate plasmonic wave packets that can propagate along the nanowire by exciting superpositions of surface plasmon resonances. By using an appropriately chirped pulse, it is possible to transiently achieve localization of the excitation at the distal end of the nanowire. Such designed coherent superpositions will allow realizing spatiotemporal control of plasmonic excitations for enhancing nonlinear responses in plasmonic "circuits".