Wang Lu, Wang Ying, Zhou Liang, Liu Jing-Yao, Wu Zhijian
Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China; University of Science and Technology of China, Hefei 230026, China.
J Colloid Interface Sci. 2025 Feb 15;680(Pt B):43-52. doi: 10.1016/j.jcis.2024.11.069. Epub 2024 Nov 15.
Direct seawater electrolysis greatly alleviates the shortage of freshwater resources, emerging as a promising approach for hydrogen production. Unfortunately, the slow kinetics of oxygen evolution reaction (OER) and the complex seawater environment, especially the chloride oxidation reaction (ClOR), pose significant challenges for the design of direct seawater electrolysis catalysts. For the sake of enhancing corrosion resistance to chloride ions (Cl), an alkaline environment is settled for increasing the potential difference between OER and competitive ClOR. NiFe-LDH has been recognized as a benchmark catalyst in alkaline environment owing to its unique advantages. However, in strongly alkaline environment, the deposition of Mg(OH) and Ca(OH) at the cathode limits the overall efficiency of direct seawater electrolysis. In this study, we have investigated the underlying effect of four different interlayer anions (PO, SO, CO, and NO) on the OER activity, selectivity, and pH application range of NiFe-LDH using density functional theory. Furthermore, we have explored the intrinsic correlations between electronic structure and catalytic performance. Our results confirm that the interlayer anions play a favorable role in promoting OER activity. Among them, NiFe-LDH with PO remarkably outperforms the other interlayer anions in terms of OER activity and selectivity, reducing the OER overpotential (η) to 0.29 V and overcoming the limitations associated with high pH conditions. Most importantly, there is a linear relationship between η and the charge transferred from the interlayer anion to the catalyst surface (ΔQ), implying that the interlayer anions are able to regulate the catalytic activity through essential charge transfer. This study provides theoretical insights into the design and development of advanced OER catalysts that can simultaneously suppress ClOR for direct seawater electrolysis.
直接海水电解极大地缓解了淡水资源短缺问题，成为一种很有前景的制氢方法。不幸的是，析氧反应（OER）的缓慢动力学以及复杂的海水环境，尤其是氯化物氧化反应（ClOR），给直接海水电解催化剂的设计带来了重大挑战。为了增强对氯离子（Cl）的耐腐蚀性，采用碱性环境以增加OER与竞争性ClOR之间的电位差。由于其独特的优势，NiFe-LDH已被公认为碱性环境中的基准催化剂。然而，在强碱性环境中，阴极处Mg(OH)和Ca(OH)的沉积限制了直接海水电解的整体效率。在本研究中，我们使用密度泛函理论研究了四种不同层间阴离子（PO、SO、CO和NO）对NiFe-LDH的OER活性、选择性和pH应用范围的潜在影响。此外，我们还探索了电子结构与催化性能之间的内在关联。我们的结果证实，层间阴离子在促进OER活性方面发挥了有利作用。其中，含PO的NiFe-LDH在OER活性和选择性方面明显优于其他层间阴离子，将OER过电位（η）降低至0.29 V，并克服了与高pH条件相关的限制。最重要的是，η与从层间阴离子转移到催化剂表面的电荷（ΔQ）之间存在线性关系，这意味着层间阴离子能够通过基本的电荷转移来调节催化活性。这项研究为先进OER催化剂的设计和开发提供了理论见解，这些催化剂可同时抑制直接海水电解中的ClOR。
