Liardet Laurent, Hu Xile
Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
ACS Catal. 2018 Jan 5;8(1):644-650. doi: 10.1021/acscatal.7b03198. Epub 2017 Dec 6.
The water-splitting reaction provides a promising mechanism to store renewable energies in the form of hydrogen fuel. The oxidation half-reaction, the oxygen evolution reaction (OER), is a complex four-electron process that constitutes an efficiency bottleneck in water splitting. Here we report a highly active OER catalyst, cobalt vanadium oxide. The catalyst is designed on the basis of a volcano plot of metal-OH bond strength and activity. The catalyst can be synthesized by a facile hydrothermal route. The most active pure-phase material (CoVO ) is X-ray amorphous and provides a 10 mA cm current density at an overpotential of 347 mV in 1 M KOH electrolyte when immobilized on a flat substrate. The synthetic method can also be applied to coat a high-surface-area substrate such as nickel foam. On this three-dimensional substrate, the CoVO catalyst is highly active, reaching 10 mA cm at 254 mV overpotential, with a Tafel slope of only 35 mV dec. This work demonstrates CoVO as a promising electrocatalyst for oxygen evolution and validates M-OH bond strength as a practical descriptor in OER catalysis.
水分解反应提供了一种很有前景的机制，可将可再生能源以氢燃料的形式储存起来。氧化半反应，即析氧反应（OER），是一个复杂的四电子过程，构成了水分解中的效率瓶颈。在此，我们报道了一种高活性的OER催化剂——钴钒氧化物。该催化剂是基于金属-OH键强度与活性的火山图设计的。该催化剂可通过简便的水热路线合成。最具活性的纯相材料（CoVO ）是X射线非晶态的，当固定在平面基底上时，在1 M KOH电解液中，在347 mV的过电位下可提供10 mA cm 的电流密度。该合成方法也可用于涂覆高表面积基底，如泡沫镍。在这种三维基底上，CoVO 催化剂具有高活性，在254 mV过电位下达到10 mA cm ，塔菲尔斜率仅为35 mV dec 。这项工作证明CoVO 是一种很有前景的析氧电催化剂，并验证了M-OH键强度作为OER催化中一种实用描述符的作用。
