Carbon‐based heteroatom‐coordinated single‐atom catalysts (SACs) are promising candidates for energy‐related electrocatalysts because of their low‐cost, tunable catalytic activity/selectivity, and relatively homogeneous morphologies. Unique interactions between single metal sites and their surrounding coordination environments play a significant role in modulating the electronic structure of the metal centers, leading to unusual scaling relationships, new reaction mechanisms, and improved catalytic performance. This review summarizes recent advancements in engineering of the local coordination environment of SACs for improved electrocatalytic performance for several crucial energy‐convention electrochemical reactions: oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, CO2 reduction reaction, and nitrogen reduction reaction. Various engineering strategies including heteroatom‐doping, changing the location of SACs on their support, introducing external ligands, and constructing dual metal sites are comprehensively discussed. The controllable synthetic methods and the activity enhancement mechanism of state‐of‐the‐art SACs are also highlighted. Recent achievements in the electronic modification of SACs will provide an understanding of the structure–activity relationship for the rational design of advanced electrocatalysts.

MXenes, a family of two-dimensional (2D) transition-metal carbide and nitride materials, are supposed to be promising pseudocapacitive materials because of their high electronic conductivity and hydrophilic surfaces. MXenes, prepared by removing the “A” elements of their corresponding MAX phases by hydrofluoric acid (HF) or LiF–HCl etching, possess abundant terminal groups like −F, −OH, and −O groups. It has been proven that the MXenes with fewer −F terminal groups and more −O groups showed a higher pseudocapacitor performance. In organic reactions, −OH and −X (X = halogen) groups could turn to ether groups in strong nucleophilic reagent. Inspired by that, herein, we report an n-butyllithium-treated method to turn the −F and −OH terminal groups to −O groups on the Ti3C2T x MXenes. Two types of Ti3C2T x MXenes prepared by either HF or LiF–HCl etching were systematically investigated, and a comparison with the traditional KOH/NaOH/LiOH-treated method was also carried out. It is found that most of the −F terminal groups on the Ti3C2T x MXenes can be successfully removed by n-butyllithium, and abundant −O terminal groups were formed. The n-butyllithium-treated Ti3C2T x MXenes show promising applications in high-performance pseudocapacitors. A record high capacitance of 523 F g–1 at 2 mV s–1 was obtained for the n-butyllithium-treated Ti3C2T x MXenes, and 96% capacity can remain even after 10 000 cycles.

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