Emerging electrocatalytic activities in transition metal selenides: synthesis, electronic modulation, and structure-performance correlations

Engineering high-performance, stable, and scalable electrocatalysts that can meet clean energy demands and solve environmental problems are urgently needed. Despite having been developed only recently, transition metal selenides (TMSes) have emerged as rapidly growing electrocatalysts due to their tunable bandgap, atom environments, and electronic structures, as well as multiphase structures with different conductivities. On account of the lack of guiding reviews, this progress report summarizes the synthetic methods, modulation strategies, structure-performance correlations, and the corresponding emerging electrocatalytic activities of TMSes. First, we focus on discussing the state-of-the-art synthetic strategies and techniques in engineering nanostructured and electrocatalytic TMSes. Particularly, we give detailed pathways for tuning their catalytic atoms and bond microenvironments, including phase modulation, construction of heterojunction, defect engineering, and element doping. Furthermore, the representative electrocatalytic applications and breakthroughs of structured TMSes for efficient and eco-friendly energy conversion technologies have been briefly discussed, such as water splitting, O2 reduction, CO2 reduction, and N2 reduction. Overall, this cutting-edge and comprehensive review will offer multidisciplinary guidance on discussing the experimental and theoretical progress of TMSes and unveiling the current critical challenges for their future developments in electrocatalytic energy conversion systems.