Abstract
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Carbon-based materials have been attracting intense interest for electrocatalysis due to their various
merits, such as abundance, low cost, high conductivity and tunable molecular structures. However,
to date, the electrochemical activities of these electrocatalysts are mainly attributed to different active
dopants (e.g. N, B, P or S), leading to a common concept that heteroatom doping is essential for
carbon-based electrocatalysts. Recently, we presented a new concept where the specific topological
defects could activate the oxygen reduction reaction (ORR) and developed a facile method to create
such unique defects. Subsequent research has extended this new mechanism to other reactions, such
as the hydrogen and oxygen evolution reactions (HER and OER) and confirmed that heteroatom doping
is not essential but that these defects can serve as actives sites for electrochemical reactions. This new
theory then creates a new research direction in electrocatalysis. In this short review, we summarise the
origin and presentation of the defect mechanism concept, the possible topological defect structures
that are effective for electrochemical reactions, the formation of desirable defects, the challenges in the
synthesis and characterization of typical defects and future research directions on the electrochemical
defect mechanism.