Synthesis, structure and electrochemical properties of an inorganic-organic hybrid CuII-CeIII heterometallic germanotungstate

A new 1:2-type inorganic-organic hybrid Cu-II-Ce-III heterometallic germanotungstate (GT) derivative KNa2H9[enH(2)](2) [Cu(en)(2)(H2O)](2)[Cu(en)(2)](2){Cu(en)(2)[Ce(alpha-GeW11O39)(2)](2)}.14H(2)O (1) (en = ethylenediamine) was obtained by simultaneously introducing Cu2+ and Ce4+ cations to the trivacant Keggin-type [A-alpha-GeW9O34](10-) system in the help of extra Na2WO4 center dot 2H(2)O and en ligand under hydrothermal conditions and was further characterized by elemental analyses, IR spectrum, thermogravimetric (TG) analysis and single-crystal X-ray diffraction. 1 exhibits a 1-D Cu-II-Ce-III heterometallic chain architecture by tetrameric (Cu(en)(2)[Ce(alpha-GeW11O39)(2)](2))(24-) units via K+ cations. Moreover, its solid-state electrochemical and electrocatalytic properties have been measured in 0.5 mol L-1 Na2SO4 + H2SO4 aqueous solution by entrapping them in a carbon paste electrode, indicating that 1 displays apparent electrocatalytic activities for nitrite, bromate and hydrogen peroxide reduction. (C) 2016 Elsevier B.V. All rights reserved.