Tuning the Interaction between Ruthenium Single Atoms and the Second Coordination Sphere for Efficient Nitrogen Photofixation

Abstract

Orienting the migration of photogenerated electrons to the target active single atoms instead of dissipation at inert sites is crucial to improve the photocatalytic activity of single‐atom catalysts, but remains a challenge. Herein, it is demonstrated that the strong interaction between Ru single atoms and the second coordination sphere significantly enriches photogenerated electrons at Ru active sites and boosted N2 photofixation activity. The extra RuCo coordination from the strong interaction with the second coordination sphere is observed over CoO‐supported Ru single atoms (RuO+Co/CoO) relative to the weakly interacting ones (RuO/CoO). For N2 photofixation, RuO+Co/CoO exhibits an ammonia production rate of 306 µmol gcat.−1 h−1 without any sacrificial agents at room temperature, which is 4.6 times that of RuO/CoO. Mechanistic studies reveal that RuCo coordination in RuO+Co/CoO serves as an additional photoelectron transfer channel. Such channel promotes the accumulation of photoelectrons that excite from O to Co atoms on Ru active sites, facilitating the photoreduction of N2 into NH3 process. The concept of the second coordination sphere modulation offers a powerful platform toward rational design of highly efficient single‐atom catalysts for N2 fixation and beyond.

Boosting Photocatalytic Nitrogen Fixation via In Situ Constructing Bi Metal Active Sites over BiOBr/BiOI Heterojunction

“…This energy barrier varies from different samples, and it decreases from 2.506 eV for BiOBr to 2.391 eV for BiOBr/BiOI and 2.318 eV for BiOBr/BiOI/Bi. [ 41,42 ] Furthermore, the free energy of adsorption of *NH 2 products rises from −1.563 eV for BiOBr to −1.645 eV for BiOBr/BiOI and −2.318 eV for BiOBr/BiOI/Bi. The adsorption energy of N 2 molecules on the surface of the three catalysts is shown in Figure 11d.…”

Electronic Modulation of the Interaction between Fe Single Atoms and WO2.72–x for Photocatalytic N2 Reduction

“…However, single metal atoms with high surface energies are very mobile and tend to aggregate in synthetic and catalytic processes. , Aggregation of single metal atoms to nanoparticles is inevitable if they are fixed on the catalyst surface only by electrostatic attraction. Some recent studies illustrated that if there are significant charge transfers between the support and single metal atoms, the agglomeration of single metal atoms can be efficiently inhibited due to the unique metal–support interactions that lead to reversible structural changes at the nanoscale. , Moreover, there is an upshift of the d-band center because of M 1 –O–M 2 formation (M 1 and M 2 stand for single atom and metal in the support, respectively) and enhancement of N 2 adsorption. , Reducible WO 2.72 is known to be redox-active and is a potential support to stabilize single metal atoms in an extended system. The semiconductor material functions as an electron reservoir and influences the charge transfer degree at metal/support interfaces .…”

“…26,27 M 2 stand for single atom and metal in the support, respectively) and enhancement of N 2 adsorption. 28,29 Reducible WO 2.72 is known to be redox-active and is a potential support to stabilize single metal atoms in an extended system. The semiconductor material functions as an electron reservoir and influences the charge transfer degree at metal/support interfaces.…”

Recent Progress of Diatomic Catalysts: General Design Fundamentals and Diversified Catalytic Applications

“…[4][5][6] Besides, most SACs still have some problems, such as low metal loading, small contact area between single atom and supporting materials, and relatively weak interaction, which greatly limit the practical application of monatomic catalysts in many kinds of catalytic fields. [7][8][9][10] Based on this phenomenon, diatomic catalysts (DACs) as a family member of monoatomic catalyst have started to emerge in recent years. [11][12][13][14][15] By introducing the second metal atom to construct "homogeneous element DACs" or "heterogeneous element diatomic catalysts DACs," some application limitations In recent years, some experiments and theoretical work have pointed out that diatomic catalysts not only retain the advantages of monoatomic catalysts, but also introduce a variety of interactions, which exceed the theoretical limit of catalytic performance and can be applied to many catalytic fields.…”