MSGID: 1:317/3 63f83d7c   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    2D Janus materials could harvest abundant hydrogen fuel    
      
     Date:   
         February 23, 2023   
     Source:   
         Springer   
     Summary:   
         Several studies have predicted that the water splitting reaction   
         could be catalyzed by certain groups of 2D materials -- each   
         measuring just a few atoms thick. New calculations present a new   
         group of four 2D materials whose two sides each feature a different   
         molecular composition, which could be especially well suited to   
         the task.   
      
      
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   FULL STORY   
   ==========================================================================   
   Several studies have predicted that the water splitting reaction   
   could be catalysed by certain groups of 2D materials -- each measuring   
   just a few atoms thick. One particularly promising group are named 2D   
   Janus materials, whose two sides each feature a different molecular   
   composition. Through new calculations detailed in EPJ B, Junfeng Ren and   
   colleagues at Shandong Normal University in China present a new group   
   of four 2D Janus materials, which could be especially well suited to   
   the task.   
      
      
   ==========================================================================   
   Since hydrogen releases an abundance of energy when combusted, with   
   only water as a by-product, it is now widely seen as an excellent   
   alternative to fossil fuels. Splitting water molecules involves a   
   'redox reaction,' where electrons and holes participate in reduction and   
   oxidation reactions. Since they are excellent semiconductors, 2D Janus   
   materials are particularly well suited to catalysing this reaction. When   
   an electron in a semiconductor's insulating 'valence band' absorbs a   
   photon, it is excited to the material's 'conduction band,' leaving behind   
   a positively charged hole. In turn, these materials as both source and   
   acceptors of electrons -- allowing redox reactions to occur more readily.   
      
   In their theoretical study, Ren's team examined a group of four of these   
   materials: with one surface composed of either selenium or tellurium, and   
   the other from either bromine or iodine -- with both sides sandwiching a   
   middle layer of astatine. In these semiconductors, the energies of their   
   valence and conduction bands were far enough apart to prevent electrons   
   and holes from readily recombining: allowing them to combine electrons and   
   holes to produce hydrogen and oxygen. With all four materials displaying   
   excellent stability and light absorption, the researchers believe   
   they could be incredibly promising candidates for catalysing the water   
   splitting reaction. If these results can be reproduced in experiments,   
   Ren's team hope the four materials could become a key element of the   
   global effort to eliminate our carbon emissions in the next few decades.   
      
       * RELATED_TOPICS   
             o Matter_&_Energy   
                   # Materials_Science # Civil_Engineering #   
                   Engineering_and_Construction # Nature_of_Water   
             o Earth_&_Climate   
                   # Water # Renewable_Energy # Drought_Research #   
                   Environmental_Issues   
       * RELATED_TERMS   
             o Materials_science o Metallurgy o Mica o Polymer o Hygroscopy   
             o Nanoparticle o Smoulder o Molecule   
      
   ==========================================================================   
   Story Source: Materials provided by Springer. Note: Content may be edited   
   for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Jiali Wang, Jiajun Lu, Xiuwen Zhao, Guichao Hu, Xiaobo Yuan,   
      Junfeng Ren.   
      
         Two-dimensional Janus AsXY (X = Se, Te;   
         Y = Br, I) monolayers for photocatalytic water   
         splitting.   
      
         The European Physical Journal B, 2023; 96 (2) DOI:   
         10.1140/epjb/s10051- 023-00486-2   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/02/230223132906.htm   
      
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