Optimizing construction of fern-like Co₃O₄@Ni₃Fe-LDH p-n heterojunction for boosting photo-assisted-electronic N₂ reduction into NH₃ and DFT calculation

Herein, a fern-like p-n heterojunction by anchoring Ni3Fe-LDH nanoplates onto Co3O4 nanoneedles have been optionally constructed. Essentially, p-n heterojunction ensured to induce strong built-in electric field, and inherit interfacial electron redistribution. Based on their compatible and well-matched electronic band structures, a staggered type-II photo-generated electron/holes transfer pathway have been elaborated by density functional theory calculation (DFT), in situ irradiation X-ray photoelectron spectroscopy (XPS), and fluorescent decay. This band bending and charge migrating module conferred the architecture with strong redox ability, sufficient exciton dissociation, and admirable optoelectronic characteristics. Moreover, the heterostructure acquired broad absorption spectrum to exhibit outperforming photocatalytic effect. Totally, this electron redistribution at the hierarchical interface, a type-II scheme charge-transfer pathway and the oxygen defects would lead to high efficiency in solar light assisted N2 reduction. Typically, Co@Ni3Fe-2 catalyst exhibited the highest NH3 production rate of 16.15 mu g h-1 mgcat.-1 and Faraday efficiency (FE) of 31.57% at -0.6 V vs. RHE in 0.1 M Na2SO4 solution. Fortunately, with light exposure, the NH3 production rate and FE could increase by 27.9% and 18.1% than that under dark. This work would provide a plausible attitude towards the design of high efficient photocatalyst for artificial photosynthesis with multi-functionalized coupling effect.