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Nanoconfinement is an effective strategy to improve the kinetic and thermodynamic properties of the Mg/MgH 2 system. However, current nanoconfinement approaches including porous scaffolds impregnation and surface anchoring can hardly obtain high loading, agglomeration resistant, and air-stable Mg nanoparticles. Herein, we report a novel strategy for preparing carbon scaffold in situ nanoconfined Mg hydrogen storage materials. The 12.2 nm MgBu 2 nanosheets precipitated by solvent displacement are encapsulated in ZIF-8 to prepare MgBu 2 @ZIF-8, which are then pyrolyzed at 800°C to obtain Mg@C nanocomposites with 8.7 nm Mg embedded in a carbon scaffold. First principles calculations have demonstrated that the addition of MgBu 2 promotes the nucleation and growth of ZIF-8 to form MgBu 2 @ZIF-8. It is worth noting that the loading rate of Mg@C-3 sample reaches a record high of 76.3% and exhibits outstanding hydrogen storage performances. Surprisingly, the enthalpy of hydrogen absorption/desorption sharply decreases to −62.0/63.1 kJ mol−1 H 2. Mg@C-3 can absorb 4.4 wt% H 2 at 200°C and desorb 4.0 wt% H 2 at 250°C, and the activation energy for hydrogen absorption/desorption is reduced to a staggering 53.1/74.2 kJ mol−1 H 2. Moreover, Mg@C-3 shows high cycling stability and antioxidant performance. This work opens a novel approach for the development of nanoconfined Mg nanocomposites with excellent performances. [Display omitted] • An in-situ growth-thermal decomposition method is developed for the nanoconfined Mg. • The loading rate of 8.7 nm Mg in Mg@C-3 reached a record high of 76.3%. • The ab/de-sorption activation energy of Mg@C-3 decreased to 53.1/74.2 kJ mol−1 H 2. • The ab/de-sorption enthalpy of Mg@C-3 decreased to −62.0/63.1 kJ mol−1 H 2. • Mg@C-3 exhibits excellent cycling stability and antioxidant performance. [ABSTRACT FROM AUTHOR]

Abstract Several tree ring samples in Zhengzhou, China, were collected to research the pollution elements variation history and the application of dendrochemistry in urban environmental pollution research. Bark and soil samples were also collected in the study area. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to analyse the concentrations of pollution elements in Cedrus deodara (Roxb.). The results indicated that the variations in pollution elements concentrations in the tree rings were roughly consistent with the history of the Zhengzhou No. 3 cotton mill (GM3). The autocorrelation coefficients determined for the element concentrations indicated that Zn and Pb were translocated within tree rings to a certain degree, especially Zn, and that Cu was not translocated within tree rings. We also found that the accumulation of Pb in the bark was extremely high, which indicated that trees are prone to Pb absorption from the atmosphere, not soil. This research reveals the history of different pollution elements in the environment and demonstrates that dendrochemical methods represent an effective component in an environmental monitoring programme. [ABSTRACT FROM AUTHOR]

Over the past 40 years, brownfield remediation has become an important issue of urban economic transition and revival, providing many social, economic, and environmental benefits to cities. Identifying urban candidate brownfield sites is an essential task of brownfield projects, but few attempts have been made to create a comprehensive dataset of their spatial distribution in China. This paper presents a new method for identifying urban candidate brownfield sites using multi-source data, including current urban land use maps, Baidu heat maps, business data, and Baidu street view. Our method for identifying urban candidate brownfield sites consists of four steps: (1) preparing and processing the basic data while screening potential contaminated sites using a current urban land use map, mapping the geographical coordinates of operating and non-operating businesses, and calculating the Baidu heat index; (2) integrating spatial multi-source data; (3) screening the intensity of use and the degree of abandonment for suspected sites in Baidu street view; and (4) conducting field surveys. The method was proposed and tested using a case study in the central region of Changchun, China, and 146 candidate brownfield sites were identified. The new data that we collected and our methodology can be used as quantitative and universally applicable tools within a discriminant analytical model framework, for urban geography, urban design, and landscape architecture. The resulting maps for urban candidate brownfields could also provide local government agencies with a technical reference for brownfield remediation. • A new method was proposed for identifying urban candidate brownfield sites. • Multi-source data were proposed for calculating the indicators. • The three impact factors had different effects on the identification results. • 146 urban candidate brownfield sites in Changchun were calculated and analyzed. • The Baidu heat map can be used to identify urban brownfield sites. [ABSTRACT FROM AUTHOR]