Salmanion Mahya, Najafpour Mohammad Mahdi
Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
Center of Climate Change and Global Warming, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran.
Inorg Chem. 2021 Apr 19;60(8):6073-6085. doi: 10.1021/acs.inorgchem.1c00561. Epub 2021 Mar 29.
Ni/Fe oxides are among the most widely used catalysts for water splitting. This paper outlines a new approach to synthesize Ni-Fe layered double hydroxides (Ni-Fe LDHs) for oxygen-evolution reaction (OER). Herein, we show that a dendrimer with carboxylate surface groups (generation 3.5) could react with Ni(II) ions to form a precatalyst for OER. During electrochemical OER, this precatalyst converted to Ni-Fe LDH, which is an efficient catalyst toward OER in the presence of Fe(III) ions. The catalyst was characterized by a number of methods and applied for OER using fluorine-doped tin oxide (FTO), Au, Pt, Ni foam, and glassy carbon electrodes. The catalyst shows a current density of 100 mA/cm on the surface of the Ni foam, using only 297 mV overpotential and with the Tafel slope of 60.8 mV/decade. A current density of 50 mA/cm on the surface of Au or Pt requires 333 and 317 mV overpotentials, respectively. The slopes of the Tafel plots for the catalyst on Au, GC, and Pt are 52.5, 47.1, and 37.4 mV/decade, respectively. The dendrimer resulted in a large dispersibility and an increase in active sites of Ni-Fe LDH, as well as the formation of Ni-Fe LDH.
镍铁氧化物是水分解中使用最广泛的催化剂之一。本文概述了一种合成用于析氧反应（OER）的镍铁层状双氢氧化物（Ni-Fe LDHs）的新方法。在此，我们表明具有羧酸盐表面基团的树枝状聚合物（3.5代）可与Ni(II)离子反应形成OER的预催化剂。在电化学OER过程中，这种预催化剂转化为Ni-Fe LDH，在Fe(III)离子存在下，它是一种高效的OER催化剂。该催化剂通过多种方法进行了表征，并使用氟掺杂氧化锡（FTO）、金、铂、泡沫镍和玻碳电极用于OER。该催化剂在泡沫镍表面显示出100 mA/cm²的电流密度，仅需297 mV的过电位，塔菲尔斜率为60.8 mV/decade。在金或铂表面达到50 mA/cm²的电流密度分别需要333和317 mV的过电位。该催化剂在金、玻碳和铂上的塔菲尔曲线斜率分别为52.5、47.1和37.4 mV/decade。树枝状聚合物导致Ni-Fe LDH具有较大的分散性和活性位点的增加，以及Ni-Fe LDH的形成。
