Dynamic Reconfiguration and Local Polarization of NiFe-Layered Double Hydroxide-Bi2MoO6- x Heterojunction for Enhancing Piezo-Photocatalytic Nitrogen Oxidation to Nitric Acid.

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.

Electronic configuration inversion in CdIn2S4 for efficient photocatalytic hydrogen peroxide generation coupled with selective benzylamine oxidation.

Vacancies engineering has sparked a huge interest in enhancing photocatalytic activity, but monovacancy simultaneously conducts as either electron or hole acceptor and redox reaction, worsening charge transfer and catalytic performance. Here, the concept of electronic inversion has been proposed through the simultaneous introduction of surface oxygen and S vacancies in CdIn2S4 (OSv-CIS). Consequently, under mild conditions, the well-designed OSv-CIS-200 demonstrated a strong rate of N-benzylidenebenzylamine production (2972.07 µmol g-1 h-1) coupled with Hydrogen peroxide (H2O2) synthesis (2362.33 µmol g-1 h-1) (PIH), which is 12.4 times higher than that of CdIn2S4. Density functional theory (DFT) simulation and characterization studies demonstrate that oxygen is introduced into the lattice on the surface of the material, reversing the charge distribution of the S vacancy and enhancing the polarity of the total charge distribution. It not only provides a huge built-in electric field (BEF) for guiding the orientation of the charge transfer, but also acts as a long-distance active site to accelerate reaction and prevent H2O2 decomposition. Our work offers a straightforward connection between the atomic defect and intrinsic properties for designing high-efficiency materials.