Understanding the Structural-Dependent Photocatalytic Antibacterial Activity: a Case Study of Ag Modified BiVO4

Abstract

In this work, Ag/BiVO 4 heterostructural photocatalysts were developed in order to reveal exceptional structuraldependent photoinduced charge migration kinetics as well as the underlying photocatalytic antibacterial dynamic process. The structure-dependent interface of BiVO 4 and Ag nanoparticles was successfully constructed to improve the photoinduced interface charge transfer efficiency and interface correlation. DFT calculation indicated that a net charge of about 0.33 e between Ag and tz-BiVO 4 was achieved by extraordinary interface charge transfer, being far larger than that between Ag and ms-BiVO 4. Larger net charge has consequences on mobility of charge carriers of tz-BiVO 4 that can raise the migration and separation of charge carriers for Ag/tz-BiVO 4 heterojunction. Fine interfacial contact between Ag and tz-BiVO 4 led to the optimized photocatalytic performance toward E. coli inactivation, being predominately higher than that of tz-BiVO 4 , ms-BiVO 4 , and Ag/ms-BiVO 4 catalysts. Besides photocatalytic activity, the thermocatalytic inactivation activity of Ag/tz-BiVO 4 also exhibited a factor of about 7.2 and 3.1 times higher than that of tz-BiVO 4 and Ag/ms-BiVO 4. Trapping and EPR measurements suggested that the structural-dependent photocatalytic activity of Ag/BiVO 4 mainly originated from the pronounced variation of the capability to produce H 2 O 2 active species, where the capability of generating H 2 O 2 over Ag/tz-BiVO 4 is highly accelerated. Moreover, it cannot be ignored that this study provides an ideal candidate for many aspects, such as environmental and water pollution caused by pathogenic microorganisms and disinfection of medical materials, food packaging, household materials, and public places, etc.

Facilitating space charge directional separation for enhancing photocatalytic CO2 reduction over tetragonal BiVO4

“…3d), the binding energies ranging from 528 eV to 535 eV can be deconvoluted into three subpeaks at 529.8 eV, 531.1 eV and 532.6 eV, which can be assigned to lattice oxygen, oxygen vacancies and adsorbed oxygen, respectively. 43 In the Ag 3d spectral region (Fig. 3e), two major peaks centered at 368.0 and 374.0 eV are related to the Ag 3d 5/2 and Ag 3d 3/2 spin orbitals of metallic Ag, 44 which is consistent with the HRTEM image results.…”

Enhanced photoelectrocatalytic degradation of diclofenac sodium using a system of Ag-BiVO4/BiOI anode and Ag-BiOI cathode

“…Nevertheless, all the Ag loaded photoanodes gave better photocurrent response and the highest response was 0.58 mA cm −2 . This observation clearly affirmed that as a noble metal, Ag could act as a photosensitizer absorbing photons and regulating the generation of charge carrier through direct electron transfer or dipole–dipole coupling connection 31 , 41 . Additionally, the behaviour of the electrodes with different bias potential was also examined through LSV with light on/off and it was observed that the magnitude of the transient photocurrent response increased with the applied potential (Fig.…”

“…Therefore, noble metals can act as photosensitizers promoting the absorption of visible light. Additionally, noble metals can form Schottky barrier when in contact with semiconductors when the electrons from the interface of the semiconductor move towards the noble metal 30 , 31 . This largely promote the separation of photogenerated charge carriers because electrons from the conduction band of the semiconductors can easily migrate to the conduction levels of the noble metals.…”