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The impact of Indium (In) doping upon the catalytic performance of Pd-Cu/Al 2 O 3 for carbon monoxide preferential oxidation (CO-PROX) in hydrogen (H 2 ) rich atmosphere at low temperature has been studied. A series of catalysts with extremely low palladium (Pd) loading (0.06 wt%) are synthesized by the facile co-impregnation method. When the In/copper (Cu) atomic ratio equals 0.25, Pd-Cu-In 0.25 /Al 2 O 3 can keep 40% CO conversion and 100% carbon dioxide (CO 2 ) selectivity at least 120 min at 30 °C, which is significantly superior to the catalytic performance of Pd-Cu/Al 2 O 3 . The elaborate characterization findings reveal that the added In species to Pd-Cu/Al 2 O 3 causes Indium oxide (In 2 O 3 ) to generate, which produces the interaction of In 2 O 3 with Pd-Cu/Al 2 O 3 , further promoting the dispersion of copper chloride hydroxide (Cu 2 Cl(OH) 3 ). Moreover, the modification of In facilitates the re-oxidation of Pd 0 to Pd + through reducing the formation of palladium hydride (PdH x ) during the CO-PROX reaction. Meanwhile, the addition of In leads to the decrease of Cu + electron cloud density, making it easier to be oxidized to Cu 2+ . Collectively, the easy re-oxidation of Pd 0 and Cu + is favorable to fulfill the Wacker cycle between Pd and Cu species, thus improving the catalytic performance for CO-PROX., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Redispersion is an effective method for regeneration of sintered metal-supported catalysts. However, the ambiguous mechanistic understanding hinders the delicate controlling of active metals at the atomic level. Herein, the redispersion mechanism of atomically dispersed Pt on CeO 2 is revealed and manipulated by in situ techniques combining well-designed model catalysts. Pt nanoparticles (NPs) sintered on CeO 2 nano-octahedra under reduction and oxidation conditions, while redispersed on CeO 2 nanocubes above ∼500 °C in an oxidizing atmosphere. The dynamic shrinkage and disappearance of Pt NPs on CeO 2 (100) facets was directly visualized by in situ TEM. The generated atomically dispersed Pt with the square-planar [PtO 4 ] 2+ structure on CeO 2 (100) facets was also confirmed by combining Cs-corrected STEM and spectroscopy techniques. The redispersion and atomic control were ascribed to the high mobility of PtO 2 at high temperatures and its strong binding with square-planar O 4 sites over CeO 2 (100). These understandings are important for the regulation of atomically dispersed platinum catalysts.

Atom-by-atom control of a catalyst surface is a central yet challenging topic in heterogeneous catalysis, which enables precisely confined adsorption and oriented approach of reactant molecules. Here, exposed surfaces with either consecutive Pd trimers (Pd 3 ) or isolated Pd atoms (Pd 1 ) are architected for Pd 2 Ga intermetallic nanoparticles (NPs) using reactive metal-support interaction (RMSI). At elevated temperatures under hydrogen, in situ atomic-scale transmission electron microscopy directly visualizes the refacetting of Pd 2 Ga NPs from energetically favorable (013)/(020) facets to (011)/(002). Infrared spectroscopy and acetylene hydrogenation reaction complementarily confirm the evolution from consecutive Pd 3 to Pd 1 sites of Pd 2 Ga catalysts with the concurrent fingerprinting CO adsorption and featured reactivities. Through theoretical calculations and modeling, we reveal that the restructured Pd 2 Ga surface results from the preferential arrangement of additionally reduced Ga atoms on the surface. Our work provides previously unidentified mechanistic insight into temperature-promoted RMSI and possible solutions to control and rearrange the surface atoms of supported intermetallic catalyst.

The precise identification of postural behavior plays a crucial role in evaluation of animal welfare and captive management. Deep learning technology has been widely used in automatic behavior recognition of wild and domestic fauna species. The Asian slow loris is a group of small, nocturnal primates with a distinctive locomotion mode, and a large number of individuals were confiscated into captive settings due to illegal trade, making the species an ideal as a model for postural behavior monitoring. Captive animals may suffer from being housed in an inappropriate environment and may display abnormal behavior patterns. Traditional data collection methods are time-consuming and laborious, impeding efforts to improve lorises' captive welfare and to develop effective reintroduction strategies. This study established the first human-labeled postural behavior dataset of slow lorises and used deep learning technology to recognize postural behavior based on object detection and semantic segmentation. The precision of the classification based on YOLOv5 reached 95.1%. The Dilated Residual Networks (DRN) feature extraction network showed the best performance in semantic segmentation, and the classification accuracy reached 95.2%. The results imply that computer automatic identification of postural behavior may offer advantages in assessing animal activity and can be applied to other nocturnal taxa., (© 2022. The Author(s).)

Oxygen evolution reaction (OER) is an important half-cell reaction of the electrical water splitting, for its high overpotential associated with sluggish OER kinetics. Therefore, it is critical to develop highly active and durable electrocatalysts to reduce the overpotential. Herein, ultra-small RuO 2 nanoparticles (NPs) supported on onion-like carbon (OLC) and carbon nanotube (CNT) are successfully synthesized by means of wet impregnation combined with annealing treatment, respectively. The microstructure characterization results showed OLC perfect graphitic carbon layer structure, and the RuO 2 NPs supported on the OLC possess larger particle size compared with the RuO 2 NPs supported on the CNT. Moreover, the electronic structure of Ru in RuO 2 /OLC was also optimized by the OLC support to be beneficial for the OER. The OER performance of the catalysts were investigated in 1 M KOH solution. The results show RuO 2 /OLC has a comparable OER activity to the commercial RuO 2 , but a significantly higher mass activity than the commercial RuO 2 . When compared with the RuO 2 /CNT, RuO 2 /OLC not only exhibits lower overpotential and Tafel slop, but also owns more active sites and higher TOF value, indicating the OLC support improved the OER activity of RuO 2 /OLC. Moreover, RuO 2 /OLC showed a superior stability compared with RuO 2 /CNT, which can be attributed to the excellent electrochemical oxidation-resistance of the OLC., (© 2022 IOP Publishing Ltd.)

Revealing the active phase and structure of catalyst nanoparticles (NPs) is crucial for understanding the growth mechanism and realizing the controlled synthesis of carbon nanotubes (CNTs). However, due to the high temperature and complex environment during CNT growth, precise identification of the active catalytic phase remains a great challenge. We investigated the phase evolution of cobalt (Co) catalyst NPs during the incubation, nucleation, and growth stages of CNTs under near-atmospheric pressure using an in situ close-cell environmental transmission electron microscope (ETEM). Strict statistical analysis of the electron diffractograms was performed to accurately identify the phases of the catalyst NPs. It was found that the NPs belong to an orthorhombic Co 3 C phase that remained unchanged during CNT growth, with errors in lattice spacing <5% and in angle <2°, despite changes in their morphology and orientation. Theoretical calculations further confirm that Co 3 C is the thermodynamically preferred phase during CNT growth, with the supply of carbon atoms through the surface and NP-CNT interfacial diffusion.

Light elements in the interstitial site of transition metals have strong influence on heterogeneous catalysis via either expression of surface structures or even direct participation into reaction. Interstitial atoms are generally metastable with a strong environmental dependence, setting up giant challenges in controlling of heterogeneous catalysis. Herein, we show that the desired carbon atoms can be manipulated within nickel (Ni) lattice for improving the selectivity in acetylene hydrogenation reaction. The radius of octahedral space of Ni is expanded from 0.517 to 0.524 Å via formation of Ni 3 Zn, affording the dissociated carbon atoms to readily dissolve and diffuse at mild temperatures. Such incorporated carbon atoms coordinate with the surrounding Ni atoms for generation of Ni 3 ZnC 0.7 and thereof inhibit the formation of subsurface hydrogen structures. Thus, the selectivity and stability are dramatically improved, as it enables suppressing the pathway of ethylene hydrogenation and restraining the accumulation of carbonaceous species on surface.

Supported bimetallic Pd x Cu y catalysts with precisely controlled Pd/Cu ratios were prepared and characterized by combining sample averaged and microscopic techniques. The active-site isolation effect on reactivity and reaction pathway control with different extent of Pd ensembles in acetylene hydrogenation is unravelled systematically.

Interfacial contacts within electrodes largely affect electronic transport and ion migration. Nanoscale electrode materials can achieve high reactivity, but their large interfacial contact areas lead to unavoidable impedance. Herein, a Ti3C2Tx MXene was used to construct a hybrid three-dimensional electrode material with a bilayer feature via a two-step vacuum filtration process. The introduced MXene flakes contributed to the electrode capacity, increased the electronic/ionic conductivity as a conductor and current collector, and enhanced the mechanical behaviour of the electrode by acting as a substrate. Such bilayer hybrid electrode design achieved promising cycling stability, and unlock an electrode architecture that can be applied to a wide range of two-dimensional materials.

Controllable synthesis of well-defined supported intermetallic catalysts is desirable because of their unique properties in physical chemistry. To accurately pinpoint the evolution of such materials at an atomic-scale, especially clarification of the initial state under a particular chemical environment, will facilitate rational design and optimal synthesis of such catalysts. The dynamic formation of a ZnO-supported PdZn catalyst is presented, whereby detailed analyses of in situ transmission electron microscopy, electron energy-loss spectroscopy, and in situ X-ray diffraction are combined to form a nanoscale understanding of PdZn phase transitions under realistic catalytic conditions. Remarkably, introduction of atoms (H and Zn in sequence) into the Pd matrix was initially observed. The resultant PdH x is an intermediate phase in the intermetallic formation process. The evolution of PdH x in the PdZn catalyst initializes at the PdH x /ZnO interfaces, and proceeds along the PdH x ⟨111⟩ direction., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

ZrO₂ nanoparticles, ZrO₂ (P) and ZrO₂ (H), with different tetragonal phase contents, were prepared. ZrO₂ (P) possessed higher tetragonal phase content than ZrO₂ (H). Ni/ZrO₂ catalysts (10% ( w / w )), using ZrO₂ (P) and ZrO₂ (H) as supports, were prepared using an impregnation method, and were characterized using XRD, Raman, H₂-TPR, XPS, and H₂-TPD techniques. Their catalytic performance in maleic anhydride hydrogenation was tested. The Ni/ZrO₂ (P) catalyst exhibited stronger metal-support interactions than the Ni/ZrO₂ (H) catalyst because of its higher number of oxygen vacancies and the low-coordinated oxygen ions on its surface. Consequently, smaller Ni crystallites and a higher C=C hydrogenation activity for maleic anhydride to succinic anhydride were obtained over a Ni/ZrO₂ (P) catalyst. However, the C=O hydrogenation activity of Ni/ZrO₂ (P) catalyst was much lower than that of the Ni/ZrO₂ (H) catalyst. A 43.5% yield of γ-butyrolacetone was obtained over the Ni/ZrO₂ (H) catalyst at 210 °C and 5 MPa of H₂ pressure, while the yield of γ-butyrolactone was only 2.8% over the Ni/ZrO₂ (P) catalyst under the same reaction conditions. In situ FT-IR characterization demonstrated that the high C=O hydrogenation activity for the Ni/ZrO₂ (H) catalyst could be attributed to the surface synergy between active metallic nickel species and relatively electron-deficient oxygen vacancies.

Pd-Cu/palygorskite catalysts were prepared by a wet impregnation method using palygorskite (PC/N-Pal) and ultrasonic-treated palygorskite (PC/U-Pal) as the support. Their catalytic activities toward CO oxidation at room temperature and in humid circumstances were investigated. PC/U-Pal exhibits much higher catalytic activity and stability than PC/N-Pal under the conditions of 1.0 vol.% CO and 3.3 vol.% H 2 O in the feed gas. The X-ray diffraction results indicate that quartz impurities were eliminated from the Pal after the ultrasonic treatment, and more copper species exist in the form of Cu 2 Cl(OH) 3 in PC/U-Pal. The temperature-programmed reduction results suggest that there is an enhanced reducibility of PC/U-Pal after ultrasonic treatment. Furthermore, the ultrasonic treatment can properly decrease the hydrophilicity of the support and catalyst, which may also contribute to the excellent catalytic performance.

Black phosphorene-waterborne polyurethane (BPWPU) composite polymer with 0.2 wt % of black phosphorene was synthesized. Scanning electron microscopy (SEM) was used to observe the morphology of phosphorene in polyurethane matrix, which indicated that the phosphorene distributes uniformly in the PU matrix. The flammability measurements were carried out to investigate the flame-resistant performances of phosphorene, which indicated that phosphorene could effectively restrict the degradation of the PU membrane. Compared by the pure WPU, the limiting oxygen index (LOI) of BPWPU increased by 2.6%, the heat flow determined by thermal analysis significantly decreased by 34.7% moreover, the peak heat release rate (PHRR) decreased by 10.3%., Competing Interests: The authors declare no conflict of interest.

A novel cascade photoelectrochemical (PEC) signal amplification sensing strategy was designed and applied in target DNA detection by introducing quantum dots (QD) as the accompanying tag. The CdTe QD was labeled onto a designed sequence of single stranded DNA forming S-QD, which could be further hybridized with another magnetic bead labeled conjugate, leading to a metastable structure. In the presence of the detecting target, the S-QD could be released from the metastable structure via toehold strand displacement. With the help of the designed strand (H), the target could be released and triggered the cascade amplification. In the magnetic field, the S-QD could be easily separated from the reaction mixture and coated on the F-doped tin oxide (FTO) electrode leading to the "signal on" PEC response. The designed cascade amplification photoelectrochemical strategy exhibited a detection limit of 0.76 pM target DNA, and a linear range from 1 pM to 50 nM, indicating promising application in DNA or related analysis. Moreover, compared with other tags such as fluorescent dye, the quantum material leads to less unspecific adsorption and better sensing reproducibility, due to the appropriate nano size and high quantum efficiency.

In this comment, we point out that the tractions induced by interfacial energy, which are referred to as the tractions on the central axis curve of the DNA elastic rod presented by Huang (J. Biol. Phys. 37(1), 79-90, 2011), are incorrect. The correct tractions are provided in this literature. Further, with the use of the correct tractions, we present new numerical results, which for the values given by Zaixing Huang do not give rise to the physical behavior observed for DNA by the author.