<p>Electrochemical reduction reactions, including the oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CRR), and nitrate reduction reaction (NRR), hold promise for energy conversion and storage. However, electrocatalysts exhibit slow kinetics and inactivation effects, resulting in inadequate energy efficiency and poor stability. To address these challenges, the group VIII element-based single-atom electrocatalysts (GVSAEs) were endowed with tunable electronic structures and porous carbon substrates to reduce intermediate adsorption and desorption energy barriers, which can accelerate electrochemical kinetics. This mini review summarises the recent achievements in GVSAEs with electronic structure and porous substrate engineering discussions. Furthermore, these GVSAEs are divided into non-noble iron series element (Fe, Co, and Ni) single-atom electrocatalysts and noble platinum series elements (Ru, Rh, Pd, Os, Ir, and Pt) based single-atom electrocatalysts for the ORR, HER, CRR, and NRR, where the porous substrate structure, electronic structure, and catalytic activity are discussed. Finally, conclusions and perspectives relating to future challenges and potential opportunities are provided for electrocatalysis with better performance.</p> Graphical Abstract <p></p>