Atomic level Interface catalysis: The role of doping engineering and coordination in tailoring activity, selectivity, and stability of single-atom catalysts

Single-atom catalysts (SACs) provide an ideal platform for exploring the structure-activity relationship (SAR) of various electrocatalytic reactions, owing to the tunability of their coordination environment (CE), wherein metal active sites are atomically dispersed across diverse substrates such as carbons, metal oxides, single-atom alloy (SAA), MXenes, and transition metal dichalcogenides (TMDs). Multi-heteroatom doping has proven to be an efficient method for modifying the microenvironment of SAC substrates and improving catalytic performance, selectivity, and stability in various electrochemical processes such as O₂ evolution reaction (OER), H₂ evolution reaction (HER), water splitting, CO₂ reduction reaction (CO₂RR), N₂ reduction reaction (NRR), and NO₃ reduction reaction (NO₃RR). Herein, we have discussed the importance of various SAC substrates, advanced synthesis strategies, along with recently designed approaches for multi-heteroatom doping and emphasizing the tailoring of single-atom (SA) active sites via heteroatom doping engineering across various substrates. The mechanistic understating and synergistic effects of doping engineering and CE on the catalytic activity, selectivity, and overall stability of SACs have been reviewed for various catalysis reactions. Further, this comprehensive review summarizes the existing challenges and potential prospects for utilizing dopants engineered SACs not only in electrocatalysis systems but also in energy storage devices and other applications.