A 2D/2D/2D Ti ₃ C ₂ T _x @TiO ₂ @MoS ₂ heterostructure was achieved via a facile one-step hydrothermal strategy; it showed an excellent gas sensing performance to NO ₂ , which is mainly attributed to numerous active sites and unique three-phase heterointerfaces.

Manipulating electronic structure of alloy‐based electrocatalysts can eagerly regulate its catalytic efficiency and corrosion resistance for water splitting and fundamentally understand the catalytic mechanisms for oxygen/hydrogen evolution reactions (OER/HER). Herein, the metallic Co‐assisted Co₇Fe₃ alloy heterojunction (Co₇Fe₃/Co) embeds in a 3D honeycomb‐like graphitic carbon is purposely constructed as a bifunctional catalyst for overall water splitting. As‐marked Co₇Fe₃/Co‐600 displays the excellent catalytic activities in alkaline media with low overpotentials of 200 mV for OER and 68 mV for HER at 10 mA cm⁻². Theoretical calculations reveal the electronic redistribution after coupling Co with Co₇Fe₃, which likely forms the electron‐rich state over interfaces and the electron‐delocalized state at Co₇Fe₃ alloy. This process changes the d‐band center position of Co₇Fe₃/Co and optimizes the affinity of catalyst surface to intermediates, thus promoting the intrinsic OER/HER activities. For overall water splitting, the electrolyzer only requires a cell voltage of 1.50 V to achieve 10 mA cm⁻² and dramatically retains 99.1% of original activity after 100 h of continuous operation. This work proposes an insight into modulation of electronic state in alloy/metal heterojunctions and explores a new path to construct more competitive electrocatalysts for overall water splitting.

The picture shows Co single atom-decorated RuO₂nanoparticles anchored on nitrogen-doped ultrathin carbon nanosheet (Co_SA-RuO₂-NUCN). The bifunctional catalytic process (ORR/OER) of Co_SA-RuO₂-NUCN is also fully presented.