Dynamic Reconfiguration and Local Polarization of NiFe‐Layered Double Hydroxide‐Bi₂MoO_6−x Heterojunction for Enhancing Piezo‐Photocatalytic Nitrogen Oxidation to Nitric Acid

Abstract

Constructing heterojunctions with vacancies has garnered substantial attention in the field of piezo‐photocatalysis. However, the presence of interfacial vacancies can serve as charge‐trapping sites, leading to the localization of electrons and hindering interfacial charge transfer. Herein, dual oxygen vacancies in the NiFe‐layered double hydroxide and Bi2MoO6−x induced interfacial bonds have been designed for the piezo‐photocatalytic N2 oxidation to NO3−. Fortunately, it achieves sensational nitric acid production rates (7.23 mg g−1 h−1) in the absence of cocatalysts and sacrificial agents, which is 6.03 times of pure Bi2MoO6 that under ultrasound and light illumination. Theoretical and experimental results indicate that interfacial bonds act as “charge bridge” and “strain center” to break the carrier local effect and negative effects with piezocatalysis and photocatalysis for promoting exciton dissociation and charge transfer. Moreover, the strong electronic interaction of the interfacial bond induces internal reconstruction under ultrasound for promoting the local polarization and adsorption of N2, which accelerates the fracture of the N≡N bonds and reduces the activation energy of the reaction. The research not only establishes a novel approach for optimizing the combined effects of piezo‐catalysis and photocatalysis, but also achieves equilibrium between the synergistic impacts of vacancies and heterojunctions.

Electric effects reinforce charge carrier behaviour for photocatalysis

“…In another study, dual oxygen vacancies in the NiFe-layered double hydroxide and Bi 2 MoO 6− x induced interfacial bonds were designed for piezo-photocatalytic N 2 oxidation. 62 In this case, the interfacial bonds acted as “charge bridge” and “strain center”, which broke the charge carrier localization and negative effects and facilitated the charge transfer, thus achieving the desired nitric acid yield (7.23 mg g −1 h −1 ). The above-mentioned studies have shown a feasible method of combining piezoelectric semiconductors with narrow energy bandgap photocatalysts to form heterojunctions to improve piezo-photocatalytic performance.…”