Marvel Guntur Wijanarko, Yusak Hartanto, Maria Yuliana, Jiuan Jing Chew, Han Bing Chua, Basil T. Wong, Suryadi Ismadji, Diah Agustina Puspitasari, Wei Zhou, Agus Saptoro, Jaka Sunarso
The transition from fossil-fuel-based energy systems to sustainable hydrogen production via alkaline water electrolysis remains constrained by the sluggish kinetics of the anodic oxygen evolution reaction (OER). To mitigate the high overpotentials inherent to this four-electron transfer process, the development of high-performance electrocatalysts remains essential. Transition metal hydroxides (TMHs) have recently emerged as a promising class of catalysts due to their electronic tunability and greater synthetic flexibility compared to traditional oxides. However, bulk TMHs have low conductivity and limited stability, hindering their practical application in alkaline water electrolysis. To overcome these problems, 2D LDHs, high-entropy materials and heterostructure are utilised to enhance the structural stability and maximise active sites. Furthermore, the development of metal hydroxide organic frameworks (MHOFs), a subset of metal organic frameworks (MOFs) that integrates high-porosity organic architectures with the intrinsic catalytic activity of metal hydroxide layers, demonstrates higher degree of flexibility in electrocatalyst design to further improve their anodic OER performance. This review categorises TMH research into three generations: the first generation (simple transition metal hydroxides), the second generation (LDHs, high entropy LDHs, heterostructures), and the third generation (MHOFs). This classification illustrates the clear structural progression of TMH-based materials and serves as a roadmap for the ongoing development of advanced OER electrocatalyst for TMHs. Finally, this review outlines recent advances within each generation of TMHs, providing a comprehensive discussion of the latest MHOF developments and their future outlooks. © 2026 The Author(s)
Department of Chemical and Energy Engineering, Faculty of Engineering and Science, Curtin University Malaysia, CDT 250, Sarawak, Miri, 98009, Malaysia; Curtin Malaysia Research Institute (CMRI), Curtin University Malaysia, CDT 250, Sarawak, Miri, 98009, Malaysia; Research Centre for Sustainable Technologies, Faculty of Engineering, Computing, and Science, Swinburne University of Technology, Jalan Simpang Tiga, Sarawak, Kuching, 93350, Malaysia; Department of Chemical Engineering, Widya Mandala Surabaya Catholic University, Kalijudan 37, Surabaya, 60114, Indonesia; Collaborative Research Centre for Zero Waste and Sustainability, Kalijudan 37, Surabaya, 60114, Indonesia; Department of Chemical Engineering, Faculty of Engineering, Brawijaya University, MT Haryono 167, Malang, 65145, Indonesia; Western Australian School of Mines, Curtin University, Locked Bag 30, Kalgoorlie Western Australia, 6433, Australia; State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 210009, China
