Mo-BiVO₄/Ca-BiVO₄ Homojunction Nanostructure-Based Inverse Opals for Photoelectrocatalytic Pharmaceutical Degradation under Visible Light

Abstract

Homojunction engineering has emerged as a potent strategy to evade interfacial stability issues and improve the efficiency of nanostructured metal oxide photocatalysts, though rarely combined with the enhanced light capture ability of threedimensional macroporous photonic crystal structures. Herein, the formation of nanoscale n-n + homojunctions between different Moand Ca-doped BiVO 4 nanocrystals in the skeleton of photonic band gap (PBG) engineered inverse opals is introduced as an advanced approach to simultaneously promote visible light harvesting, electron transport, and charge separation of BiVO 4 nanomaterials for the photoelectrocatalytic degradation of pharmaceutical contaminants of emerging concern. Controlled deposition of BiVO 4 inverse opal films with tailored PBGs was combined with compositional tuning by Mo-and Ca-doping for slow-photon-assisted visible-light-activated (VLA) photocatalysis. The introduction of shallow dopant states in the Mo-, Ca-doped BiVO 4 nanoparticles with relatively weak structural distortions but significantly different donor concentrations resulted in a broad distribution of type-II homojunctions in the nanocrystalline inverse opal walls. Comparative photoelectrochemical evaluation showed that nanostructured homojunction Mo-BiVO 4 /Ca-BiVO 4 photonic films largely outperformed their individual constituents in both photocurrent generation and the VLA photocatalytic degradation rate. Moreover, they exhibited markedly improved performance in the photoelectrocatalytic degradation of tetracycline and ciprofloxacin broad-spectrum antibiotics as well as salicylic acid under visible light, validating their application potential in VLA water remediation by pharmaceutical micropollutants.

Co-assembled MoS2–TiO2 Inverse Opal Photocatalysts for Visible Light-Activated Pharmaceutical Photodegradation

“…The high surface area reaching 244 m 2 /g was estimated by applying the multipoint Brunauer–Emmett–Teller (BET) method to the pristine PC425 that originated from the enhanced mesoporosity of the nanocrystalline inverse opal skeleton. This was further corroborated by the corresponding pore size distribution determined from nonlocal density functional theory (NLDFT) analysis using the N 2 –silica desorption branch kernel (equilibrium model) at 77 K (Figure b) . Markedly increased mesopore volume ( V meso ) of 0.499 cm 3 /g was thus derived by the NLDFT pore size distribution with a maximum at 4.89 nm mesopore width, which can be related to the small anatase nanoparticle size .…”

Applications of bismuth-based nanoparticles for the removal of pollutants in wastewater: a review

“…At present, the principal strategies for utilizing Bi-based NPs in water remediation include photocatalysis, 46,55,56 electrocatalysis, 57,58 and photoelectrochemical catalysis. 59–61 Despite exhibiting promising performance in laboratory conditions, the translation of Bi-based NPs to large-scale industrial applications encounters several challenges. For instance, while some Bi-based NPs demonstrate high activity, persistent issues include the separation of photogenerated electrons (e − ) and holes (h + ), as well as inadequate selectivity during the process.…”

Mo-BiVO4 Photocatalytically Modified Ceramic Ultrafiltration Membranes for Enhanced Water Treatment Efficiency

“…Nonetheless, its practical activity fails to meet its theoretical photocurrent density under solar light illumination due to rapid charge recombination and slow oxidation kinetics [4,5]. Transition metal ions, such as molybdenum (Mo), have been employed to enhance the performance of BiVO 4 under solar light [4][5][6]. In our recent study [6], a Mo-BiVO 4 inverse opal film was deposited onto a fluorine-doped tin oxide (FTO) coated glass substrate.…”

“…Transition metal ions, such as molybdenum (Mo), have been employed to enhance the performance of BiVO 4 under solar light [4][5][6]. In our recent study [6], a Mo-BiVO 4 inverse opal film was deposited onto a fluorine-doped tin oxide (FTO) coated glass substrate. Similar approaches have been reported in literature, where these inverse opal films were applied onto FTOcoated glasses using either dip-coating [7], drop-coating [8], or spin-coating [9] techniques.…”

“…Hence, the imperative development of efficient degradation methods to mitigate its environmental impact cannot be overstated. Photocatalysis has arisen as a promising method for the degradation of tetracycline contaminants in aqueous environments [6,[24][25][26][27][28][29]. As aforementioned, this process utilizes photocatalysts to generate reactive oxygen species under irradiation with ultraviolet (UV) or visible light.…”