Recent advances in transition metal‐based electrocatalysts for seawater electrolysis

Abstract

Summary Low carbon‐footprint hydrogen generated from water splitting has attracted wide attention, which can satisfy future industrial requirements as a promising method. Compared with the scarcity of available freshwater, seawater splitting becomes worldwide research focus due to abundant seawater resources. Nevertheless, precious metal catalysts featured with high cost and low stability in seawater restrict its practical application. Recently, great progress of transition metals' (TM) compounds has been made toward seawater electrolysis, which made the process more practically feasible due to its abundant reserve and corrosion resistance. Therefore, it is necessary to understand the recent advances and challenges of TM‐based electrocatalysts in seawater; wherein few reviews have been reported so far. Herein, in this review, a comprehensive introduction of recently reported TM‐based electrocatalysts and advanced strategies for seawater electrolysis are provided. In particular, the challenges and perspectives of TM‐based electrocatalysts in the field of commercial application are briefly concluded at the end.

Critical challenges and opportunities for the commercialization of alkaline electrolysis: high current density, stability, and safety

“…However, introducing additives incurs additional costs 193 and potentially leads to unexpected side reactions. 194 Jin et al presented a strategy to enhance the activity of the catalyst by introducing a Lewis acid layer on the catalyst surface, thereby engineering the local reaction environment.…”

Rapid synthesis of efficient Mo-based electrocatalyst for the hydrogen evolution reaction in alkaline seawater with 11.28% solar-to-hydrogen efficiency

“…[1][2][3] Currently, the production of H 2 by electrochemical seawater splitting has emerged as one of the most promising strategies. [4][5][6][7] Over the past decade, commercial Pt/C has been regarded as the state-of-the-art hydrogen evolution reaction (HER) electrocatalyst in alkaline water splitting. Unfortunately, its high cost and barely satisfactory elemental abundance hampers its large-scale implementation.…”

One-step hydrothermal synthesis of Se-doped NiTe electrocatalysts for efficient hydrogen production from saline water assisted by anodic iodide oxidation

“…In particular, the existence of Cl − ions, which are abundant in seawater, would cause the chlorine evolution reaction (CER) at high anodic voltages/high current densities, not only competing with the oxygen evolution reaction (OER) leading to a low faradaic efficiency, but also generating corrosive and environmentally unfriendly chlorine-containing species shortening the lifetime of materials and components of the electrolyzer. 3,4…”

“…E-mail: xiongdehua@whut.edu.cn b Songshan Lake Materials Laboratory, Dongguan 523808, P. R. China. E-mail: zhipeng-yu@outlook.com; liu.lifeng@sslab.org.cn a formidable challenge due to the complex composition of seawater, which contains various anions and metal cations, such as Cl − , SO 4 2− , Ca 2+ , and Mg 2+ . In particular, the existence of Cl − ions, which are abundant in seawater, would cause the chlorine evolution reaction (CER) at high anodic voltages/high current densities, not only competing with the oxygen evolution reaction (OER) leading to a low faradaic efficiency, but also generating corrosive and environmentally unfriendly chlorinecontaining species shortening the lifetime of materials and components of the electrolyzer.…”

“…In particular, the existence of Cl − ions, which are abundant in seawater, would cause the chlorine evolution reaction (CER) at high anodic voltages/high current densities, not only competing with the oxygen evolution reaction (OER) leading to a low faradaic efficiency, but also generating corrosive and environmentally unfriendly chlorinecontaining species shortening the lifetime of materials and components of the electrolyzer. 3,4 So far, there are several strategies proposed to address the challenges facing direct seawater electrolysis, including developing highly efficient electrocatalysts toward the OER in alkaline solution, considering the "alkaline design criterion" proposed by Strasser and co-workers. 5 For example, Wang et al used the onestep corrosion strategy to prepare NiFe-LDH and then obtained Fe-Ni-O-N electrocatalysts through low-temperature nitridation, which needed an overpotential of only 260 mV to deliver 500 mA cm −2 for the OER in alkaline seawater, successfully circumventing the CER.…”