Core-shell structured NiTe@FeOOH nanoarrays for efficient overall seawater splitting

Electrocatalytic seawater splitting to produce hydrogen has gained wide attention in recent years. However, their scale-up applications are still hindered by the lack of highly active, stable and low-cost electrocatalysts for the anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). In this work, core–shell structured nanoarrays (NiTe@FeOOH) were designed and constructed for efficient overall seawater splitting. The catalyst (NiTe@FeOOH) exhibited superior OER and HER activity, requiring overpotentials as low as 280 mV for OER and 282 mV for HER to achieve 100 mA cm−2 in seawater, respectively. When applied for overall seawater splitting, it only required a cell voltage of 1.79 V to achieve 100 mA cm−2, with high faradic efficiencies (FEs) of nearly 100 % for both OER and HER, as well as excellent durability over 100 h of continuous testing. Based on the characterization results, the strong interactions between NiTe and FeOOH, and the chloride repelling owing to the more negatively charged surface was verified to be the proper reasons for NiTe@FeOOH’s high performance and selectivity toward OER and HER. The high performance and stability of the catalyst makes it great potential for seawater splitting.