Dual‐Metal Sites Boosting Polarization of Nitrogen Molecules for Efficient Nitrogen Photofixation

Constructing nitrogen (N 2 ) adsorption and activation sites on semiconductors is the key to achieving efficient N 2 photofixation. Herein, Mn–W dual‐metal sites on WO 3 are designed toward efficient N 2 photoreduction via controlled Mn doping. Impressively, the optimal 2.3% Mn‐doped WO 3 (Mn‐WO 3 ) exhibits a remarkable ammonia (NH 3 ) production rate of 425 µmol g cat. −1 h −1 , representing the best catalytic performance among the ever‐reported tungsten oxide‐based photocatalysts for N 2 fixation. Quasi in situ synchrotron radiation X‐ray spectroscopy directly identifies that the Mn–W dual‐metal sites can enhance the polarization of the adsorbed N 2 , which is beneficial to the N 2 activation. Further theoretical calculations reveal that the increased polarization is originated from the electron back‐donation into the antibonding orbitals of the adsorbed N 2 , hence lowering the reaction energy barrier toward the N 2 photofixation. The concept of dual sites construction for inert molecule activation offers a powerful platform toward rational design of highly efficient catalysts for nitrogen fixation and beyond.