Liu Hao, Shen Wei, Jin Huanyu, Xu Jun, Xi Pinxian, Dong Juncai, Zheng Yao, Qiao Shi-Zhang
School of Chemical Engineering and Advanced Materials, The University of Adelaide, 5005, Adelaide, SA, Australia.
College of Chemistry and Chemical Engineering, Lanzhou University, 730000, Lanzhou, China.
Angew Chem Int Ed Engl. 2023 Nov 13;62(46):e202311674. doi: 10.1002/anie.202311674. Epub 2023 Oct 11.
A highly selective and durable oxygen evolution reaction (OER) electrocatalyst is the bottleneck for direct seawater splitting because of side reactions primarily caused by chloride ions (Cl ). Most studies about OER catalysts in seawater focus on the repulsion of the Cl to reduce its negative effects. Herein, we demonstrate that the absorption of Cl on the specific site of a popular OER electrocatalyst, nickel-iron layered double hydroxide (NiFe LDH), does not have a significant negative impact; rather, it is beneficial for its activity and stability enhancement in natural seawater. A set of in situ characterization techniques reveals that the adsorption of Cl on the desired Fe site suppresses Fe leaching, and creates more OER-active Ni sites, improving the catalyst's long-term stability and activity simultaneously. Therefore, we achieve direct alkaline seawater electrolysis for the very first time on a commercial-scale alkaline electrolyser (AE, 120 cm electrode area) using the NiFe LDH anode. The new alkaline seawater electrolyser exhibits a reduction in electricity consumption by 20.7 % compared to the alkaline purified water-based AE using commercial Ni catalyst, achieving excellent durability for 100 h at 200 mA cm .
由于主要由氯离子（Cl⁻）引起的副反应，高选择性和耐用的析氧反应（OER）电催化剂是直接海水分解的瓶颈。大多数关于海水中OER催化剂的研究都集中在Cl⁻的排斥上，以减少其负面影响。在此，我们证明了Cl⁻在一种常见的OER电催化剂镍铁层状双氢氧化物（NiFe LDH）的特定位点上的吸附并没有显著的负面影响；相反，它有利于其在天然海水中的活性和稳定性增强。一系列原位表征技术表明，Cl⁻在所需的Fe位点上的吸附抑制了Fe的浸出，并产生了更多的OER活性Ni位点，同时提高了催化剂的长期稳定性和活性。因此，我们首次在商业规模的碱性电解槽（AE，电极面积120 cm²）上使用NiFe LDH阳极实现了直接碱性海水电解。与使用商业Ni催化剂的碱性纯水基AE相比，新型碱性海水电解槽的耗电量降低了20.7%，在200 mA cm⁻²的电流密度下实现了100 h的优异耐久性。
