Photoinduced nitrogen spillover enables ammonia synthesis on iron–aluminium dual-site catalysts

Despite the development of the Haber–Bosch process, ammonia synthesis under mild conditions remains challenging due to the high bond energy (945 kJ mol⁻ 1 ) of the N≡N triple bond. Both thermal- and photocatalytic processes often suffer from the intrinsic scaling relationship between N 2 activation and NH 3 desorption efficiencies. Here we report that the photocatalytic process over an AlFe nanoalloy catalyst provides a promising solution through a photoinduced nitrogen spillover reaction mechanism. Fe acts as the primary active site for N 2 adsorption and dissociation. The transferred photoexcited electrons from Al to Fe enhance N 2 activation. Al serves as a secondary active site, facilitating N spillover from Fe to Al sites under photoexcitation, promoting NH 3 desorption. This dual-site strategy enables an ammonia synthesis rate of 8.6 mmol g cat −1  h −1 at 4.28 W cm −2 without additional thermal input under ambient pressure. The performance surpasses that of conventional industrial Fe catalysts under thermocatalytic conditions. This study proposes a photoassisted active site modulation strategy for efficient ammonia synthesis catalyst to circumvent scaling relationships.