ALBERT

Description: Conversion of carbon dioxide (CO2) to carbon monoxide (CO) and other value-added carbon products is an important challenge for clean energy research. Here we report modular optimization of covalent organic frameworks (COFs), in which the building units are cobalt porphyrin catalysts linked by organic struts through imine bonds, to prepare a catalytic material for aqueous electrochemical reduction of CO2 to CO. The catalysts exhibit high Faradaic efficiency (90%) and turnover numbers (up to 290,000, with initial turnover frequency of 9400 hour(-1)) at pH 7 with an overpotential of -0.55 volts, equivalent to a 26-fold improvement in activity compared with the molecular cobalt complex, with no degradation over 24 hours. X-ray absorption data reveal the influence of the COF environment on the electronic structure of the catalytic cobalt centers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lin, Song -- Diercks, Christian S -- Zhang, Yue-Biao -- Kornienko, Nikolay -- Nichols, Eva M -- Zhao, Yingbo -- Paris, Aubrey R -- Kim, Dohyung -- Yang, Peidong -- Yaghi, Omar M -- Chang, Christopher J -- New York, N.Y. -- Science. 2015 Sep 11;349(6253):1208-13. doi: 10.1126/science.aac8343. Epub 2015 Aug 20.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Berkeley, CA 94720, USA. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ; Department of Chemistry, University of California, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ; Department of Chemistry, University of California, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China. ; Department of Chemistry, University of California, Berkeley, CA 94720, USA. ; Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA. ; Department of Chemistry, University of California, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA. Kavli Energy Nanoscience Institute, Berkeley, CA 94720, USA. ; Department of Chemistry, University of California, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Kavli Energy Nanoscience Institute, Berkeley, CA 94720, USA. King Fahd University of Petroleum and Minerals, Dhahran 34464, Saudi Arabia. yaghi@berkeley.edu chrischang@berkeley.edu. ; Department of Chemistry, University of California, Berkeley, CA 94720, USA. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA. Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA. yaghi@berkeley.edu chrischang@berkeley.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26292706" target="_blank"〉PubMed〈/a〉

Description: Just over a century ago, Lewis published his seminal work on what became known as the covalent bond, which has since occupied a central role in the theory of making organic molecules. With the advent of covalent organic frameworks (COFs), the chemistry of the covalent bond was extended to two- and three-dimensional frameworks. Here, organic molecules are linked by covalent bonds to yield crystalline, porous COFs from light elements (boron, carbon, nitrogen, oxygen, and silicon) that are characterized by high architectural and chemical robustness. This discovery paved the way for carrying out chemistry on frameworks without losing their porosity or crystallinity, and in turn achieving designed properties in materials. The recent union of the covalent and the mechanical bond in the COF provides the opportunity for making woven structures that incorporate flexibility and dynamics into frameworks. Authors: Christian S. Diercks, Omar M. Yaghi