Synthesis of N‐Doped Highly Graphitic Carbon Urchin‐Like Hollow Structures Loaded with Single‐Ni Atoms towards Efficient CO 2 Electroreduction

Abstract The rational design of single‐atom catalysts featuring excellent conductivity, highly accessible discrete active sites and favorable mass transfer is crucial for electrocatalysis but remains challenging. In this study, a reliable Ni‐catalyzed and Ni‐templated strategy is developed to synthesize a single‐atom catalyst by transforming metallic Ni into single‐Ni atoms anchored on hollow porous urchin‐like (HPU) N‐doped carbon (NC) (designated as Ni‐NC(HPU)), which possesses high crystallinity and sufficient Ni‐N 4 moiety (2.4 wt %). The unique hollow thorns on the surface, good conductivity and large external surface area facilitate electron/mass transfer and exposure of single‐Ni sites. As a result, the Ni‐NC(HPU) catalyst exhibits remarkable activity and high stability for CO 2 electroreduction. Moreover, this synthetic strategy can also be facilely extended to prepare distinct hollow porous architectures with similar components, such as the wire‐ and sphere‐like ones.