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4Ni–Al layered double hydroxide (LDH) precursors were prepared by the following three methods: constant pH coprecipitation, variable pH coprecipitation and urea hydrolysis. The 4Ni–Al mixed metal oxide (MMO) catalysts were obtained by the calcination of LDH precursors at 600 °C, and their catalytic performances in ODHP from 350 to 550 °C were tested. The 4Ni–Al MMO from the urea hydrolysis method showed a higher and more stable propylene selectivity of ca. 40% with propylene yield of ca.11% at 500 °C, and that from the constant pH coprecipitation method was followed, while oxidative cracking of propane occurred on the 4Ni–Al MMO from the variable pH coprecipitation method. It is considered to be closely related to the dispersion and stability of the surface Ni(II) species through comprehensive analysis of XRD, N 2 -adsorption-desorption, TEM, XPS, H 2 -TPR and In-situ electrical conductivity. The urea hydrolysis method with a low salt concentration, leading to an excellent stability of the surface Ni(II) species at high reaction temperature, should be selected to prepare Ni–Al MMO catalysts for ODHP instead of the traditional variable pH coprecipitation method with a high salt concentration. Graphic Abstract

Developing renewable energy sources and controlling water pollution are critical but challenging problems. Urea oxidation (UOR) and methanol oxidation (MOR), both of which have high research value, have the potential to effectively address wastewater pollution and energy crisis problems. A three-dimensional neodymium-dioxide/nickel-selenide-modified nitrogen-doped carbon nanosheet (Nd2O3-NiSe-NC) catalyst is prepared in this study by using mixed freeze-drying, salt-template-assisted technology, and high-temperature pyrolysis. The Nd2O3-NiSe-NC electrode showed good catalytic activity for MOR (peak current density ~145.04 mA cm−2 and low oxidation potential ~1.33 V) and UOR (peak current density ~100.68 mA cm−2 and low oxidation potential ~1.32 V); the catalyst has excellent MOR and UOR characteristics. The electrochemical reaction activity and the electron transfer rate increased because of selenide and carbon doping. Moreover, the synergistic action of neodymium oxide doping, nickel selenide, and the oxygen vacancy generated at the interface can adjust the electronic structure. The doping of rare-earth-metal oxides can also effectively adjust the electronic density of nickel selenide, allowing it to act as a cocatalyst, thus improving the catalytic activity in the UOR and MOR processes. The optimal UOR and MOR properties are achieved by adjusting the catalyst ratio and carbonization temperature. This experiment presents a straightforward synthetic method for creating a new rare-earth-based composite catalyst.

A series of hollow VO x /SiO 2 nanofiber catalysts (nV/S-f) with vanadium content ranging from 0.25 wt % to 4.0 wt % were prepared by electrospinning-calcination, and characterized by ICP-MS, XRD, N 2 adsorption–desorption, SEM, XPS, UV–Vis-DRS and H 2 -TPR. Subsequently, the performance of these catalysts in the oxidative dehydrogenation of propane (ODHP) was evaluated. It was found that vanadium species with high dispersivity were obtained when the V content was less than 1.5 wt %. By comparison, 1.0V/S-f catalyst had the best catalytic performance, especially in terms of the propylene selectivity at high-temperature: ~ 77% at 550 °C and ~ 74% at 575 °C. In contrast to the conventional impregnation technique, the catalyst with one-dimensional nanostructure has more catalytic advantages. Graphical Abstract

A series of hollow VO.sub.x/SiO.sub.2 nanofiber catalysts (nV/S-f) with vanadium content ranging from 0.25 wt% to 4.0 wt% were prepared by electrospinning-calcination, and characterized by ICP-MS, XRD, N.sub.2 adsorption-desorption, SEM, XPS, UV-Vis-DRS and H.sub.2-TPR. Subsequently, the performance of these catalysts in the oxidative dehydrogenation of propane (ODHP) was evaluated. It was found that vanadium species with high dispersivity were obtained when the V content was less than 1.5 wt%. By comparison, 1.0V/S-f catalyst had the best catalytic performance, especially in terms of the propylene selectivity at high-temperature: 77% at 550 °C and 74% at 575 °C. In contrast to the conventional impregnation technique, the catalyst with one-dimensional nanostructure has more catalytic advantages.

4Ni-Al layered double hydroxide (LDH) precursors were prepared by the following three methods: constant pH coprecipitation, variable pH coprecipitation and urea hydrolysis. The 4Ni-Al mixed metal oxide (MMO) catalysts were obtained by the calcination of LDH precursors at 600 °C, and their catalytic performances in ODHP from 350 to 550 °C were tested. The 4Ni-Al MMO from the urea hydrolysis method showed a higher and more stable propylene selectivity of ca. 40% with propylene yield of ca.11% at 500 °C, and that from the constant pH coprecipitation method was followed, while oxidative cracking of propane occurred on the 4Ni-Al MMO from the variable pH coprecipitation method. It is considered to be closely related to the dispersion and stability of the surface Ni(II) species through comprehensive analysis of XRD, N.sub.2-adsorption-desorption, TEM, XPS, H.sub.2-TPR and In-situ electrical conductivity. The urea hydrolysis method with a low salt concentration, leading to an excellent stability of the surface Ni(II) species at high reaction temperature, should be selected to prepare Ni-Al MMO catalysts for ODHP instead of the traditional variable pH coprecipitation method with a high salt concentration.

Developing renewable energy sources and controlling water pollution are critical but challenging problems. Urea oxidation (UOR) and methanol oxidation (MOR), both of which have high research value, have the potential to effectively address wastewater pollution and energy crisis problems. A three-dimensional neodymium-dioxide/nickel-selenide-modified nitrogen-doped carbon nanosheet (Nd O -NiSe-NC) catalyst is prepared in this study by using mixed freeze-drying, salt-template-assisted technology, and high-temperature pyrolysis. The Nd O -NiSe-NC electrode showed good catalytic activity for MOR (peak current density ~145.04 mA cm and low oxidation potential ~1.33 V) and UOR (peak current density ~100.68 mA cm and low oxidation potential ~1.32 V); the catalyst has excellent MOR and UOR characteristics. The electrochemical reaction activity and the electron transfer rate increased because of selenide and carbon doping. Moreover, the synergistic action of neodymium oxide doping, nickel selenide, and the oxygen vacancy generated at the interface can adjust the electronic structure. The doping of rare-earth-metal oxides can also effectively adjust the electronic density of nickel selenide, allowing it to act as a cocatalyst, thus improving the catalytic activity in the UOR and MOR processes. The optimal UOR and MOR properties are achieved by adjusting the catalyst ratio and carbonization temperature. This experiment presents a straightforward synthetic method for creating a new rare-earth-based composite catalyst.

It is vitally important that scientists are able to describe their work simply and concisely to the public, especially in an open access online journal. The simple summary consists of no more than 200 words in one paragraph and contains a clear statement of the problem addressed, the aims and objectives, pertinent results, conclusions from the study, and how they will be valuable to society. This should be written for a lay audience, i.e., no technical terms without explanations. No references are cited, and no abbreviations included. Submissions without a simple summary will be returned directly. Developing renewable energy sources and controlling water pollution are critical but challenging problems. Urea oxidation (UOR) and methanol oxidation (MOR), both of which have high research value, have the potential to effectively address wastewater pollution and energy crisis problems. A three-dimensional neodymium-dioxide/nickel-selenide-modified nitrogen-doped carbon nanosheet (Nd[sub.2]O[sub.3]-NiSe-NC) catalyst is prepared in this study by using mixed freeze-drying, salt-template-assisted technology, and high-temperature pyrolysis. The Nd[sub.2]O[sub.3]-NiSe-NC electrode showed good catalytic activity for MOR (peak current density ~145.04 mA cm[sup.−2] and low oxidation potential ~1.33 V) and UOR (peak current density ~100.68 mA cm[sup.−2] and low oxidation potential ~1.32 V); the catalyst has excellent MOR and UOR characteristics. The electrochemical reaction activity and the electron transfer rate increased because of selenide and carbon doping. Moreover, the synergistic action of neodymium oxide doping, nickel selenide, and the oxygen vacancy generated at the interface can adjust the electronic structure. The doping of rare-earth-metal oxides can also effectively adjust the electronic density of nickel selenide, allowing it to act as a cocatalyst, thus improving the catalytic activity in the UOR and MOR processes. The optimal UOR and MOR properties are achieved by adjusting the catalyst ratio and carbonization temperature. This experiment presents a straightforward synthetic method for creating a new rare-earth-based composite catalyst.

Methanol oxidation (MOR) and urea oxidation (UOR) have been considered for new types of fuel cells, but the lack of highly active nonnoble metal catalysts restricts such cells. A NiCo-modified biomass carbon (milk as the carbon source)-based catalyst with a 3D structure is synthesized by using salt templates. The results show that 3D-C-NiCo (1:1) exhibits excellent MOR and UOR properties with a potential of 1.33 V vs. RHE and 1.35 V vs. RHE at 10 mA cm−2, respectively. MOR and UOR reactions not only can replace the oxygen evolution reaction (OER) in consumption of electrolytic water but also can effectively degrade wastewater pollution rich in methanol and urea.

Current fishway design guidelines are mostly derived from large anadromous fish species, with scarce species-specific data for small-bodied stream cyprinids such as Acrossocheilus fasciatus. This study investigated the upstream passage capacity of the cyprinid fish A. fasciatus over low-head weirs in relation to body length through controlled flume experiments. We quantified the passage success rate (PSR), behavioral strategies, and key kinematic metrics of upstream movement. Results showed that, under the specific experimental conditions, passage performance and strategy usage pattern were significantly associated with body length. Trial groups with larger mean body length showed a higher proportion of pure leaping strategy (PLS), mean body length per trial group exhibited an extremely strong positive linear relationship with mean leap distance (R² = 0.96, p < 0.001). Conversely, groups with smaller mean body length showed a higher proportion of Leaping-Swimming Strategy (LSS) usage. The association between body length and leap height was weaker. Under the specific hydraulic and structural conditions tested in this study, we observed the following trends: a weir drop of 25-30 cm allowed partial passage of A. fasciatus; the fixed 45° sloped crest profile used in this experiment was associated with prevalent adoption of the LSS by small-bodied individuals (≤13 cm); a downstream pool depth >30 cm and an inter-weir pool length >50 cm were sufficient to accommodate the observed leaping kinematics. These findings provide observational data from a single laboratory configuration for understanding the passage-related bio-behavioral characteristics of small-bodied mountain stream fishes such as A. fasciatus. All values reported are preliminary observations under controlled conditions, and their potential relevance to engineering design requires validation through multi-condition comparative experiments and field monitoring.