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Identifying ecological protection priority areas (EPPAs) in municipal areas is essential for accurate ecological restoration and ensuring sustainable regional development. Xianyang represents a typical medium-sized city that is currently grappling with the dual challenges of ecological restoration and urban development. This study employed a multi-criteria method to evaluate ecological importance, considering both ecosystem services and ecological vulnerability. Based on this, ecological corridors and pinch points that enhance ecological connectivity were delineated using the circuit theory. Subsequently, the integrity of ecosystems is assessed from structural and functional perspectives to ensure their health and stability. With the support of Geographic Information System (GIS) technology, the three important areas for ecological protection were integrated to designate EPPAs. The results showed that: (1) the extremely important area spans 1956.44 km2, primarily made up of forests and grasslands. (2) There were found to be 19 ecological sources, 26 ecological corridors, and 23 ecological pinch points. (3) With excellent ecosystem integrity, the region was dominated by eco-lands, which accounted for 2692.71 km2. (4) In the end, this study identified 3328.83 km2 of EPPAs, 32.65 % of the study area. These are primarily located in the northern mountains and major watersheds. Human activities are found as the most important factor for the overall spatial variations in the area. A multi-level framework was developed to establish a continuous, comprehensive, and systematic method for identifying EPPAs, thereby enhancing ecological restoration, protection, and the sustainable use of regional ecosystems.

Abstract Electrochemical nitrate reduction to ammonia offers an attractive solution to environmental sustainability and clean energy production but suffers from the sluggish *NO hydrogenation with the spin–state transitions. Herein, we report that the manipulation of oxygen vacancies can contrive spin−polarized Fe1−Ti pairs on monolithic titanium electrode that exhibits an attractive NH3 yield rate of 272,000 μg h−1 mgFe −1 and a high NH3 Faradic efficiency of 95.2% at −0.4 V vs. RHE, far superior to the counterpart with spin−depressed Fe1−Ti pairs (51000 μg h–1 mgFe –1) and the mostly reported electrocatalysts. The unpaired spin electrons of Fe and Ti atoms can effectively interact with the key intermediates, facilitating the *NO hydrogenation. Coupling a flow−through electrolyzer with a membrane-based NH3 recovery unit, the simultaneous nitrate reduction and NH3 recovery was realized. This work offers a pioneering strategy for manipulating spin polarization of electrocatalysts within pair sites for nitrate wastewater treatment.

Abstract A highly efficient Ruddlesden‐Popper structure anode material with a formula of Sr3Fe1.3Mo0.5Ni0.2O7‐δ (RP‐SFMN) has been developed for hydrocarbon fueled solid oxide fuel cells (HF‐SOFC) application. It is demonstrated that a nanostructured RP‐SFMN anode decorated with in‐situ exsolved Ni nanoparticles (Ni@RP‐SFMN) has been successfully prepared by annealing the anode in reducing atmosphere similar to the operating conditions. The phase compositions, valence states, morphologies, and electrocatalytic activities of RP‐SFMN material have been characterized in detail. In addition, the in‐situ exsolution mechanism of the metallic Ni phase from the parent oxide is clearly explained by using density function theory calculation. The peak output power density at 800°C is significantly enhanced from 0.163 to 0.409 W/cm2 while the electrode polarization resistance is effectively lowered from 0.96 to 0.30 Ω cm2 by the substitution of B‐site Fe by Ni, which is attributed to the improved electrocatalytic activities induced by the in‐situ exsolved Ni nanocatalysts. Moreover, the single cell with RP‐SFMN anode exhibits good stability in 3% H2O humidified H2 and syngas for 110 and 60 h at 800°C, respectively. Our findings indicate that RP‐SFMN is a greatly promising anode candidate of HF‐SOFCs due to its good electrochemical performance and stability during the operation.

Electrochemical ammonia (NH3) synthesis from nitrate reduction (NITRR) offers an appealing solution for addressing environmental concerns and the energy crisis. However, most of the developed electrocatalysts reduce NO3- to NH3 via a hydrogen (H*)-mediated reduction mechanism, which suffers from undesired H*-H* dimerization to H2, resulting in unsatisfactory NH3 yields. Herein, we demonstrate that reversed I1Cu4 single-atom sites, prepared by anchoring iodine single atoms on the Cu surface, realized superior NITRR with a superior ammonia yield rate of 4.36 mg h-1 cm-2 and a Faradaic efficiency of 98.5% under neutral conditions via a proton-coupled electron transfer (PCET) mechanism, far beyond those of traditional Cu sites (NH3 yield rate of 0.082 mg h-1 cm-2 and Faradaic efficiency of 36.5%) and most of H*-mediated NITRR electrocatalysts. Theoretical calculations revealed that I single atoms can regulate the local electronic structures of adjacent Cu sites in favor of stronger O-end-bidentate NO3- adsorption with dual electron transfer channels and suppress the H* formation from the H2O dissociation, thus switching the NITRR mechanism from H*-mediated reduction to PCET. By integrating the monolithic I1Cu4 single-atom electrode into a flow-through device for continuous NITRR and in situ ammonia recovery, an industrial-level current density of 1 A cm-2 was achieved along with a NH3 yield rate of 69.4 mg h-1 cm-2. This study offers reversed single-atom sites for electrochemical ammonia synthesis with nitrate wastewater and sheds light on the importance of switching catalytic mechanisms in improving the performance of electrochemical reactions. [ABSTRACT FROM AUTHOR]

The structures and electronic properties of bimetallic oxide CrW2O9 clusters supported on the perfect and defective MgO(001) surfaces with three different color centers, FS0, FS+, and FS2+ centers, respectively, have been investigated by density functional theory calculations. Our results show that the configurations, adsorption energies, charge transfers, and bonding modes of dispersed CrW2O9 clusters are sensitive to the charge states of the FS centers. Compared with the gas-phase configuration, the CrW2O9 clusters supported on the defective surfaces are distorted dramatically, which exhibit different chain structures. On the perfect MgO surface, the depositions of clusters do not involve obvious charge transfer, while the situation is quite different on the defective MgO(001) surfaces in which significant electron transfer occurs from the surface to the cluster. Interestingly, this effect becomes more remarkable for electron-rich oxygen vacancies (FS 0 center) than that for electron-poor oxygen vacancies (FS+ and FS2+ centers). Furthermore, our work reveals a progressive Brønsted acid sites where spin density preferentially localized around the Cr atoms not the W atoms for all kinds of FS-centers, indicating the better catalytic activities can be expected for CrW2O9 cluster on defective MgO(001) surfaces with respect to the W3O9 cluster. [ABSTRACT FROM AUTHOR]