An Amorphous Nickel–Iron‐Based Electrocatalyst with Unusual Local Structures for Ultrafast Oxygen Evolution Reaction. Issue 28 (17th May 2019) - Chen, Gao
Abstract: Rationally designing active and durable catalysts for the oxygen evolution reaction (OER) is of primary importance in water splitting. Perovskite oxides (ABO3 ) with versatile structures and multiple physicochemical properties have triggered considerable interest in the OER. The leaching of A site cations can create nanostructures and amorphous motifs on the perovskite matrix, thus facilitating the OER process. However, selectively dissolving A site cations and simultaneously obtaining more active amorphous motifs derived from the B site cations remains a great challenge. Herein, a top‐down strategy is proposed to transform bulk crystalline perovskite (LaNiO3 ) into a nanostructured amorphous hydroxide by FeCl3 post‐treatment, resulting in an extremely low overpotential of 189 mV at 10 mA cm −2 . The top‐down‐constructed amorphous catalyst with a large surface area has dual NiFe active sites, where high‐valence Ni 3+ ‐based edge‐sharing octahedral frameworks are surrounded by interstitial distorted Fe octahedra and contribute to the superior OER performance. This top‐down strategy provides a valid way to design novel perovskite‐derived catalysts. Abstract : An amorphous NiFe‐based catalyst (a‐LNF(t‐d)) is constructed from LaNiO3 perovskite oxide through a top‐down strategy involving FeCl3 post‐treatment, which selectively dissolves the La ions and deposits the Fe ions. The a‐LNF(t‐d) sample, with large surface area and unusual electronic/geometrical structure shows extremely high oxygen evolution reaction (OER) activity and stability.