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The strong metal-support interaction (SMSI) has long been studied in heterogonous catalysis on account of its importance in stabilizing active metals and tuning catalytic performance. As a dynamic process taking place at the metal-support interface, the SMSI is closely related to the metal surface properties which are usually affected by the size of metal nanoparticles (NPs). In this work we report the discovery of a size effect on classical SMSI in Au/TiO 2 catalyst where larger Au particles are more prone to be encapsulated than smaller ones. A thermodynamic equilibrium model was established to describe this phenomenon. According to this finding, the catalytic performance of Au/TiO 2 catalyst with uneven size distribution can be improved by selectively encapsulating the large Au NPs in a hydrogenation reaction. This work not only brings in-depth understanding of the SMSI phenomenon and its formation mechanism, but also provides an alternative approach to refine catalyst performance. Strong metal-support interaction (SMSI) is critical in determining the catalytic performance of supported metal catalysts. Here the authors report a phenomenon of size-dependent classical SMSI in Au/TiO 2 catalyst where larger Au particles are more prone to be encapsulated than smaller ones.

Selective hydrogenation of acetylene in excess ethylene is an important reaction in both fundamental study and practical application. Pd-based catalysts with high intrinsic activity are commonly employed, but usually suffer from low selectivity. Pd single-atom catalysts (SACs) usually exhibit outstanding ethylene selectivity due to the weak π-bonding ethylene adsorption. However, the preparation of high-loading and stable Pd SACs is still confronted with a great challenge. In this work, we report a simple strategy to fabricate Pd SACs by means of reducing conventional supported Pd catalysts at suitable temperatures to selectively encapsulate the co-existed Pd nanoparticles (NPs)/clusters. This is based on our new finding that single atoms only manifest strong metal-support interaction (SMSI) at higher reduction temperature than that of NPs/clusters. The derived Pd SACs (Pd 1 /CeO 2 and Pd 1 /α-Fe 2 O 3 ) were applied to acetylene selective hydrogenation, exhibiting much improved ethylene selectivity and high stability. This work offers a promising way to develop stable Pd SACs easily.

Metal-support interaction predominately determines the electronic structure of metal atoms in single-atom catalysts (SACs), largely affecting their catalytic performance. However, directly tuning the metal-support interaction in oxide supported SACs remains challenging. Here, we report a new strategy to subtly regulate the strong covalent metal-support interaction (CMSI) of Pt/CoFe 2 O 4 SACs by a simple water soaking treatment. Detailed studies reveal that the CMSI is weakened by the bonding of H + , generated from water dissociation, onto the interface of Pt-O-Fe, resulting in reduced charge transfer from metal to support and leading to an increase of C-H bond activation in CH 4 combustion by more than 50 folds. This strategy is general and can be extended to other CMSI-existed metal-supported catalysts, providing a powerful tool to modulating the catalytic performance of SACs. A simple water soaking treatment significantly weakened the strong covalent metal-support interaction between the atomically dispersed Pt and CoFe 2 O 4 , which leads to an enhanced activity towards methane combustions by 55 times. This work highlights the critical role of altering the coordination structure of single-atom active sites and provides a new strategy to modulate metal-support interaction regulation.

The discoveries and development of the oxidative strong metal–support interaction (OMSI) phenomena in recent years not only promote new and deeper understanding of strong metal–support interaction (SMSI) but also open an alternative way to develop supported heterogeneous catalysts with better performance. In this review, the brief history as well as the definition of OMSI and its difference from classical SMSI are described. The identification of OMSI and the corresponding characterization methods are expounded. Furthermore, the application of OMSI in enhancing catalyst performance, and the influence of OMSI in inspiring discoveries of new types of SMSI are discussed. Finally, a brief summary is presented and some prospects are proposed.

In order to effectively repair groundwater pollution and remove petroleum hydrocarbons, two petroleum hydrocarbon degrading bacteria SYT-1 and SYT-2 were isolated from long-term petroleum hydrocarbon contaminated groundwater. The rescreening experiments showed that the degradation rates of SYT-1 and SYT-2 were 65.16 % and 52.52 %, respectively. SYT-1 and SYT-2 were identified as Moraxella and Acinetobacter. The degrading bacteria SYT-1 and SYT-2 were identified as Moxa and Acinetobacter by physiological and biochemical characteristics and 16S rDNA sequencing. The experimental results provide strain resources and technical support for bioremediation of petroleum pollution in groundwater.

In this essay, I examine Nathaniel Hawthorne’s humanism in Young Goodman Brown and The Minister’s Black Veil. I argue that Hawthorne promotes a humanist world that prizes the intrinsic value of man above religious zeal or political ideology. In each of the two stories, the humanist world was inaugurated by its protagonist, whom I will analyse through invoking Prometheus, who was known for giving fire to humanity and being punished for it.

The creep camber of 32m high-speed railway box girder causes periodic track longitudinal level irregularity, so it is necessary to strictly and accurately control the line change caused by creep to ensure the operation safety. The traditional analysis is mainly done by manual work. Based on the longitudinal level data of dynamic track inspection, this paper uses wavelet decomposition and moving-average filter to study the end location of box girder. the longitudinal level at the girder’s end can be extracted and the line state can be analyzed automatically. The results show that: compared with other time-frequency analysis methods, the proposed method can accurately locate the end of the box girder, and has good applicability.

The spiritual journey that Larry from The Razor’s Edge makes after his traumatizing war experience deserves to be examined and its significance elucidated. Individuation, the central concept of Jungian psychology, offers a lens. In this interpretation, Larry’s journey is understood as an individuation process whose three stages are represented by the shadow, the anima and the Self, all personified by the novel’s characters. Just as individuation should be the goal of individual growth, Larry’s spiritual journey exemplifies a solution to the spiritual crisis plaguing the historical background that the novel is set in.

The spiritual journey that Larry from The Razor's Edge makes after his traumatizing war experience deserves to be examined and its significance elucidated. Individuation, the central concept of Jungian psychology, offers a lens. In this interpretation, Larry's journey is understood as an individuation process whose three stages are represented by the shadow, the anima and the Self, all personified by the novel's characters. Just as individuation should be the goal of individual growth, Larry's spiritual journey exemplifies a solution to the spiritual crisis plaguing the historical background that the novel is set in.

Iodine is one of the essential trace elements in the human body, and excessive or insufficient intake will affect human health. To ensure the safety of drinking water resources, the spatial distribution of iodine content and migration enrichment factors in shallow underground salty water in Tianjin coastal area were studied. The results show that the iodine (as I − ) content of shallow groundwater ranges from not detected (ND) to 1320 μg/L, and high iodine groundwater (100–300 μg/L) and super-high iodine groundwater (> 300 μg/L) account for 37.5% of the groundwater samples, distributed in the east, west, central and south of the study area; iodine-deficient groundwater (< 25 μg/L) accounts for 10% of the groundwater samples, and iodine-suitable groundwater (25–100 μg/L) accounts for 15% of the groundwater samples. From north to south and from northwest to southeast, the shallow groundwater in the study area changed from freshwater and brackish water to saline and salt water; the I − concentrations in freshwater, brackish water, and saltwater were significantly different, and the I − concentrations tended to increase with the increase of TDS concentration; the main hydrochemical types in this direction changed as HCO 3 -Ca·Na → Cl·SO 4 -Na·Mg → HCO 3 ·Cl-Na·Ca → Cl·HCO 3 -Na → Cl-Na type shift; high iodine and super-high iodine groundwater chemistry types are mainly Cl-Na type, Cl·HCO 3 -Na type and HCO 3 -Ca·Na type. The main source of iodine in groundwater is inferred to be marine sediments. Sedimentary iodine is released during dissolution of marine sediments. I − concentrations increase along with the groundwater flow. In the eastern area, the poor permeability of the aquifer due to the main lithology of mucky clay slows down the groundwater flow, and strong evaporation and concentration on account of the shallow groundwater depth contributes significantly to iodine enrichment.