Compositional and Structural Evolutions of Zn-Based Metal–Organic Frameworks During Pyrolysis

Metal–organic framework (MOF)-derived nanostructures for electrochemical applications have attracted tremendous attention; therefore, understanding of the decomposition mechanism of MOFs during thermal treatment is crucial for the design and synthesis of MOF-derived nanomaterials. Here, a systematic investigation was carried out to study the pyrolysis process of a Zn-based metal–organic framework (Zn-MOF), which revealed the compositional and structural evolution by in situ diffuse reflectance infrared Fourier transform spectroscopy, thermogravimetric analysis–differential scanning calorimetry, and X-ray diffraction methods. The continuous change of the nature of surface of pyrolytic Zn-MOF at different temperatures was also studied by the cyclic voltammetry method, described by the fractal concept of electrochemical surface. The results show that the pyrolysis of Zn-MOF occurs at ca. 450 °C and the decomposition products are amorphous carbon and ZnO. The pyrolysis temperature plays a decisive role in the formation of the porous structures of carbon matrices and the evolution of the surface geometry of the products. The presented approach would be instructive and informative for the preparation of MOF-derived nanostructures

Nuclear DNA contents and evolutionary relationships among members of the genus <i>Camellia</i>.

<p>The indicated phylogenetic relationships of the genus were constructed by using morphological data and adopted from Min et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064981#pone.0064981-Min1" target="_blank">[28]</a>. The numbers in brackets for each section represent the number of species with the measured nuclear DNA content followed by the total number of species comprising the section. The mean 2C DNA amount is indicated by • for each section, while the range is shown as a line from the minimum to maximum 2C DNA amounts. The two subgenera recognized in <i>Camellia</i> are given on the right side of the figure.</p

The relationship between genome size (pg) and latitudinal origins of 17 cultivars of <i>C. sinensis</i> var. <i>assamica</i>.

<p>The relationship between genome size (pg) and latitudinal origins of 17 cultivars of <i>C. sinensis</i> var. <i>assamica</i>.</p

Histograms of the distribution of DNA 2C-values for the 53 species of the section <i>Camellia</i>[31].

<p>The DNA 2C-values arranged by increasing DNA content (a) and the distribution of DNA 2C-values (b) for the 53 species of the section <i>Camellia</i>.</p

Nuclear DNA contents and evolutionary relationships among members of the section <i>Thea</i>[31].

<p>The phylogenetic tree of the section <i>Thea</i> was constructed by using UPGMA and Nei and Li's similarity coefficient from pairwise comparisons between the 22 species and varieties based on RAPD markers <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064981#pone.0064981-Chen1" target="_blank">[44]</a>. The estimated 2C-values for each species are shown on the right of species, while the 1C DNA amount (pg) which also equals the genome size is shown by •.</p

Comparisons of nuclear DNA amount (2C, pg) estimated with flow cytometry in different tissues of the eight species in the genus <i>Camellia</i>.

<p><i>Z. mays</i> L. cv. B73 was employed as a standard. The colors of flowers are given in the Table. All materials were collected from Kunming Institute of Botany, Chinese Academy of Sciences (KIBCAS).</p

Cytogram of fluorescence intensity of <i>C. sinensis</i> var. <i>assamica</i> and <i>Z. mays</i> L. cv. B73 nuclei isolated with an improved WPB buffer.

<p>Leaves of <i>C. sinensis</i> var. <i>assamica</i> and <i>Z. mays</i> that were treated individually (a, b) or simultaneously processed (co-chopped) (c), and stained with PI. X: Relative fluorescence; Y: Number of nuclei.</p

Nuclear DNA amount of representing species in the genus <i>Camellia</i> estimated with flow cytometry.

<p><i>Z. mays</i> L. cv. B73 was employed as a standard. Chromosome numbers were adopted from previous studies and the index to Plant Chromosome Numbers (<a href="http://mobot.mobot.org/W2T/Search/ipch.html" target="_blank">http://mobot.mobot.org/W2T/Search/ipch.html</a>). All germplasms were collected from International <i>Camellia</i> Species Garden (ICSG).</p>*<p>NA indicates that the information of chromosome number is not available.</p

Nuclear DNA amount of the section <i>Thea</i> species estimated with flow cytometry.

<p><i>Z. mays</i> L. cv. B73 was employed as a standard. Chromosome numbers were adopted from previous studies and the index to Plant Chromosome Numbers (<a href="http://mobot.mobot.org/W2T/Search/ipch.html" target="_blank">http://mobot.mobot.org/W2T/Search/ipch.html</a>). ICSG: International <i>Camellia</i> Species Garden; TRIYAAS: Tea Research Institute, Yunnan Academy of Agricultural Sciences.</p

Nuclear DNA contents and evolutionary relationships among species of the section <i>Camellia</i>[31].

<p>The phylogenetic tree was constructed based on ITS sequences <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0064981#pone.0064981-Tian1" target="_blank">[45]</a>. The estimated 2C-values are shown on the right of each species, while the 2C DNA amount (pg) is given by • for each species.</p