Fabrication of Porous Cu-Doped BiVO₄ Nanotubes as Efficient Oxygen-Evolving Photocatalysts

Abstract

We introduce a facile route to fabricate one-dimensional (1D) porous Cu 2+ -doped BiVO 4 (Cu-BVO) nanotubes with uniform size distribution and high structural stability. First, an electrospinning technique was developed to prepare the sacrificial template of polyacrylonitrile (PAN) nanofibers with a smooth surface. Second, a conformal layer of Cu-BVO nanoparticles was coated onto the PAN template through a solvothermal method to obtain the solid core−shell precursor which was finally converted into the product of porous Cu-BVO nanotubes with thermal treatment. Both experimental characterizations and theoretical calculations based on the density functional theory (DFT) calculations have revealed the crucial functionality of the appropriate band structure of the Cu 2+ -doped nanostructure and introduced beneficial defect states by Cu doping, which boosts light absorption and promotes charge migration and separation and therefore results in highly efficient photocatalytic O 2 evolution with visible-light irradiation. As a result, the porous nanotube photocatalyst with an optimal Cu 2+ doping of 5.0% exhibits an average O 2 evolution rate of 350.2 μmol h −1 g −1 , about 2.4 times more than that of pristine BVO nanotubes.

Free-Standing Electrospun W-Doped BiVO4 Porous Nanotubes for the Efficient Photoelectrochemical Water Oxidation

“…After PEC test (about 2.5 h), it remains the same surface morphology of porous nanotube (Figure 6B) as before. According to the value of photocurrent density and IPCE, the BiV 0.97 W 0.03 O 4 /Co-B nanotube exhibits the highest PEC performance ever achieved for BiVO 4 nanofiber using electrospinning (Yoon et al, 2015;Antony et al, 2016;Liu et al, 2017;He et al, 2018;Li et al, 2019). Table S1 shows the comparison of photocurrent data reported in the literature with the photocurrent value obtained in the present study.…”

“…From Figure S4, we can see that there are a lot of recombination of photogenerated electron-hole pairs both in bulk and surface during the overall reaction. The results of PEC test show that the BiV 0.97 W 0.03 O 4 /Co-B nanotube demonstrated better photocatalytic activity compared with other nanofibers that have ever been reported (Yoon et al, 2015;Antony et al, 2016;Liu et al, 2017;He et al, 2018;Li et al, 2019). The reasons can be explained as follows: first of all, the nanotube with large interface area and the porous structure can keep in good contact with the electrolyte, and enrich the active sites.…”

Enhanced Photoactivity and Photostability for Visible‐Light‐Driven Water Oxidation over BiFeO3 Porous Nanotubes by Modification of Mo Doping and Carbon Nanocoating

“…For the pure BFO PNTs, the Bi 4 f spectrum in shows two symmetry peaks located at 158.2 and 163.6 eV, which are attributed to the binding energies of Bi 4f 7/2 and Bi 4f 5/2 , respectively, being the characteristic of Bi 3 + (Figure 5a). [16] In contrast, three asymmetry peaks are observed in the Fe 2p XPS spectrum, which can be deconvoluted into three components: Fe 2p 3/2 at 711.5 eV and Fe 2p 1/2 at 725.5 eV for Fe 3 + , Fe 2p 3/2 at 709.9 eV and Fe 2p 1/2 at 723.3 eV for Fe 2 + , and two satellite peaks (Figure 5b). [17] The appearance of Fe 2 + is attributed to the presence of oxygen vacancy in BFO lattice with requirement of electrical neutrality.…”

Bi‐based photocatalysts for light‐driven environmental and energy applications: Structural tuning, reaction mechanisms, and challenges

“…The deposition and doping of metallic elements could change the photocatalytic properties mainly in the following two aspects. First, when metal ions enter the lattice, they will change the crystallinity of the Bi‐based photocatalysts or introduce defects, so as to enhance the absorption properties of light and the separation efficiency of photogenerated charges 137‐140 . For instance, Regmi et al synthesized Fe‐doped BiVO 4 with the in‐gap state between the valence band and conduction band of BiVO 4 , resulting in enhancing electron‐hole separation and improving the absorption capacity of visible light.…”