Atomic-level insights in tuning defective structures for nitrogen photofixation over amorphous SmOCl nanosheets.

Direct fixation of N 2 at room temperature by photocatalysis is the most intriguing process toward sustainable production of ammonia, where chemisorption of inert N 2 and delivery of photogenerated electrons to N N bond are recognized bottlenecks. Here, we develop a catalyst of amorphous SmOCl nanosheets (A-SmOCl) with remarkable activity for photocatalytic reduction of N 2. Impressively, the ammonia production rate of A-SmOCl reached 426 μmol·g cat. ⁻¹·h⁻¹ under light irradiation in water without any sacrificial agents. Moreover, A-SmOCl exhibited an apparent quantum efficiency of 0.32% at 420 nm. Further mechanistic studies revealed that the existence of abundant oxygen vacancies in A-SmOCl significantly improved the adsorption and activation of N 2. Meanwhile, the enhanced Sm–O covalency promoted the delivery of photogenerated electrons to chemisorbed N 2 , contributing to the superior catalytic activity of A-SmOCl. A-SmOCl exhibited the ammonia production rate of 426 μmol·g cat. ⁻¹·h⁻¹ attributed to the existence of abundant oxygen vacancies and enhanced Sm–O covalency. Image 1 • We developed a catalyst of amorphous SmOCl nanosheets (A-SmOCl) with abundant oxygen vacancies. • The NH 3 production rate of A-SmOCl reached 426 μmol·g cat. ⁻¹·h⁻¹ under light irradiation without any sacrificial agents. • A-SmOCl exhibited an apparent quantum efficiency of 0.32% at 420 nm. • The existence of abundant oxygen vacancies in A-SmOCl significantly improved the adsorption and activation of N 2. • The enhanced Sm–O covalency promoted the delivery of photogenerated electrons to chemisorbed N 2. [ABSTRACT FROM AUTHOR]