Atomically Precise Dinuclear Ni₂ Active Site-Modified MOF-Derived ZnO@NC Heterojunction toward High-Performance N₂ Photofixation

Abstract

The development of heterogeneous catalysts with atom-dispersed active sites is essential to facilitate nitrogen (N2) activation for the N2 reduction reaction (NRR). However, it remains a major challenge to tune the coordination configuration of the metal centers to further accelerate the activation kinetics. Herein, an atomically precise dinuclear Ni2 site-modified metal–organic framework (MOF)-derived ZnO@NC heterojunction (ZnO@NC-Ni2) was developed for effective N2 photofixation under mild conditions. Moreover, advanced structural characterization indicates that the most active N-coordinated bimetallic site configurations are Ni2–N6, where two Ni1–N4 moieties are shared with two N atoms. Theoretical calculations further demonstrate that the binuclear Ni2 active sites of ZnO@NC-Ni2 could adjust the N2 adsorption configuration as the side-on bridging adsorption mode (denoted as “*NN*”), while the single metal Ni1 sites of ZnO@NC-Ni1 tend to form a terminal adsorption configuration with N2 (“*NN” type). As a result, the unique electronic structure of binuclear Ni2 active sites in ZnO@NC-Ni2 tends to proceed as an associative alternating pathway, thereby decreasing the activation energy barrier of the reaction procedure and favoring the photocatalytic NRR. The present study provides a perspective to probe the relationship between the coordination architecture of earth-abundant metal active centers and NRR activities.

Magnetically induced construction of core–shell architecture Fe3O4@TiO2–Co nanocomposites for effective photocatalytic degradation of tetracycline

“…Generally speaking, the higher the photocurrent intensity of a photocatalyst, the better its photocatalytic carrier separation efficiency. 59,60…”

“…Generally speaking, the higher the photocurrent intensity of a photocatalyst, the better its photocatalytic carrier separation efficiency. 59,60 As shown in Fig. 4a, the samples demonstrate a rapid light current response to the periodic light on-off.…”

Advances in zeolitic-imidazolate-framework-based catalysts for photo-/electrocatalytic water splitting, CO2 reduction and N2 reduction applications

“…Zhang et al designed a ZnO@N-doped carbon heterojunction containing homonuclear diatomic Ni 2 sites (ZnO@NC-Ni 2 ) for the NRR. 166 As illustrated in Fig. 10, the N 2 adsorption mode at the binuclear Ni 2 site was carried out in a side-on bridging adsorption configuration, instead of the terminal adsorption configuration at the mono-metallic Ni 1 site.…”

A Self-Consistent Framework for Tailored Single-Atom Catalysts in Electrocatalytic Nitrogen Reduction

“…30,31 In the presence of several layers, the coordination in the axial direction may be prohibited and new co-adsorption configurations are presented. 32 Among numerous SACs, graphitic carbon nitride (g-C 3 N 4 ) doped with metal atoms (M@g-C 3 N 4 ) stands out for exceptional NRR performance, 6,33 because g-C 3 N 4 has many inherent advantages, such as providing abundant anchoring sites to capture metal atoms and maintaining the noble metal atoms in their neutral state. 34 aqueous solution can be simultaneously captured.…”

“…Furthermore, recent works have also suggested that the possibility of multiadsorption of surface species, such as *OH, *N 2 , and *H 2 O, on SACs, which makes the consideration of possible co-adsorption configurations of reactants and environmental species important for evaluation of the catalytic performance of designed SACs. − However, under real reaction conditions with specific applied electrode potentials and pH values, the stability of the expected co-adsorption configurations of functional ligands exhibiting high NRR catalytic performance has rarely been considered in the design of SACs. Furthermore, for the widely used 2D substrates, the layers of the substrate are difficult to control, and usually, substrates with several layers are prepared. , In the presence of several layers, the coordination in the axial direction may be prohibited and new co-adsorption configurations are presented …”