  Transition-metal-based layered double hydroxides (TM-LDHs) nanosheets are
promising electrocatalysts in the renewable electrochemical energy conversion
system, which are regarded as alternatives to noble metal-based materials. In
this review, recent advances on effective and facile strategies to rationally
design TM-LDHs nanosheets as electrocatalysts, such as increasing the number of
active sties, improving the utilization of active sites (atomic-scale
catalysts), modulating the electron configurations, and controlling the lattice
facets, are summarized and compared. Then, the utilization of these fabricated
TM-LDHs nanosheets for oxygen evolution reaction, hydrogen evolution reaction,
urea oxidation reaction, nitrogen reduction reaction, small molecule
oxidations, and biomass derivatives upgrading is articulated through
systematically discussing the corresponding fundamental design principles and
reaction mechanism. Finally, the existing challenges in increasing the density
of catalytically active sites and future prospects of TM-LDHs nanosheets-based
electrocatalysts in each application are also commented.
