Grouping Effect of Single Nickel−N4 Sites in Nitrogen‐Doped Carbon Boosts Hydrogen Transfer Coupling of Alcohols and Amines

Abstract As a new type of heterogeneous catalyst with “homogeneous‐like” activity, single‐site transition‐metal materials are usually treated as integrated but separate active centers. A novel grouping effect is reported for single Ni−N 4 sites in nitrogen‐doped carbon (Ni/NC), where an effective ligand‐stabilized polycondensation method endows Ni/NC nanocatalysts with a high content of single‐site Ni up to 9.5 wt %. The enhanced electron density at each single Ni−N 4 site promotes a highly efficient hydrogen transfer, which is exemplified by the coupling of benzyl alcohol and aniline into N ‐benzylaniline with a turnover frequency (TOF) value of 7.0 mol N ‐benzylaniline mol metal −1 h −1 ; this TOF outpaces that of reported stable non‐noble‐metal‐based catalysts by a factor of 2.