High Photoelectrocatalytic Activity Research Articles

Nanozyme-coupled photoelectrocatalytic system based on peroxidase-mimetic BiOI cathode and WO3 photoanode for efficient degradation of 3-chlorophenol

As an advanced oxidation technology, solar light-driven photoelectrocatalysis has been considered to be a sustainable method for wastewater treatment. Meanwhile, peroxidase-mimetic nanozymes have emerged as a promising tool for environmental remediation. In this work, we aimed to combine nanozyme catalysis with solar light-driven photoelectrocatalysis to achieve efficient degradation of persistent contaminant, using 3-chlorophenol (3-CP) as the representative pollutant. In the designed system, WO3 nanoplate photoanode displayed high photoelectrocatalytic activity for both 3-CP degradation and H2O2 production under simulated solar light. Furthermore, peroxidase-like BiOI with nanoflower structure was immobilized on hydrophobic carbon cathode to catalyze the oxidation of 3-CP by in situ generated H2O2. The constructed nanozyme-coupled photoelectrocatalytic system exhibited a satisfactory 3-CP degradation efficiency of 91.1 % after 90-min treatment. In addition, the possible reaction mechanisms and degradation pathways of 3-CP in such a system were discussed.

Achieving High-Efficient Photoelectrocatalytic Degradation of 4-Chlorophenol via Functional Reformation of Titanium-Oxo Clusters

Rational design of crystalline catalysts with superior light absorption and charge transfer for efficient photoelectrocatalytic (PEC) reaction coupled with energy recovery remains a great challenge. In this work, we elaborately construct three stable titanium-oxo clusters (TOCs, Ti10Ac6, Ti10Fc8, and Ti12Fc2Ac4) modified with a monofunctionalized ligand (9-anthracenecarboxylic acid (Ac) or ferrocenecarboxylic acid (Fc)) and bifunctionalized ligands (Ac and Fc). They have tunable light-harvesting and charge transfer capacities and thus can serve as outstanding crystalline catalysts to achieve efficient PEC overall reaction, that is, the integration of anodic organic pollutant 4-chlorophenol (4-CP) degradation and cathodic wastewater-to-H2 conversion. These TOCs can all exhibit very high PEC activity and degradation efficiency of 4-CP. Especially, Ti12Fc2Ac4 decorated with bifunctionalized ligands exhibits better PEC degradation efficiency (over 99%) and H2 generation than Ti10Ac6 and Ti10Fc8 modified with a monofunctionalized ligand. The study of the 4-CP degradation pathway and mechanism revealed that such better PEC performance of Ti12Fc2Ac4 is probably due to its stronger interactions with the 4-CP molecule and better •OH radical production. This work not only presents the effective combination of organic pollutant degradation and simultaneously H2 evolution reaction using crystalline coordination clusters as both anodic and cathodic catalyst but also develops a new PEC application for crystalline coordination compounds.

Fabrication of Ce MOFs/Black-TNTs and CCM/Black-TNTs as high-efficiency photoelectrode for wastewater treatment and hydrogen production

The photoelectrocatalytic (PEC) process has attracted much attention in the field of the eliminating organic pollutants in the wastewater with simultaneous hydrogen evolution in the past decade. Development of photoelectrode with high photoelectrocatalytic activity and stability is a key to degrade of various toxic pollutants via PEC technology. Here, a novel nanoflower-like metal–organic framework loaded on black titanium dioxide nanotubes (Ce MOFs/Black-TNTs) were fabricated by the hydrothermal method. Moreover, in order to improve the efficiency of photocatalytic process, cobalt-copper-manganese complex-doped black titanium dioxide nanotubes (CCM/Black-TNTs) photocathode is prepared and coupled with the Ce MOFs/Black-TNTs photoanode for hydrogen evolution at the cathode in an H-type photoreactor. The total organic carbon (TOC) removal rate of 2, 4-dichlorophenoxyacetic acid (2, 4-D) reached 98% and the yield of H2 reached 160 mmol in 120 min of reaction. The possible PEC degradation pathway of 2, 4-D at Ce MOFs/Black-TNTs photoanode was also speculated by UV–visible absorption spectroscopy and liquid chromatography combined with mass spectrometer (LC-MS). This work could open new insight into rationally designing TiO2-based photoelectrocatalysts for PEC system.

Type-I SnSe2/ZnS heterostructure improving photoelectrochemical photodetection and water splitting

Two-dimensional van der Waals heterostructures have been widely designed and applied to numerous optoelectronic devices such as photoelectrochemical (PEC)-type photodetectors, water splitting, and solar cells. The understanding of the influence of band alignment in type-I heterostructures on the photoelectric response remains incomplete yet essential for designing new optoelectronic devices. Herein, two-step physical vapor deposition is used to construct a type-I SnSe2/ZnS heterostructure, which is confirmed by ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy. The type-I heterostructure-based PEC-type photodetector exhibits excellent photoresponse, high stability, and high sensitivity in the ultraviolet-visible range. Furthermore, the photoresponsivity of SnSe2/ZnS is up to 172.60 µA W−1, which is 7.4- and 2.0-fold larger than that of pure ZnS and SnSe2, respectively. Moreover, the SnSe2/ZnS heterostructure possesses high photoelectrocatalytic activity in water splitting, and the total hydrogen production within 2 h is up to 81.25 µmol cm−2. The high PEC-type photodetector and water splitting performances in SnSe2/ZnS are due to the synergistic effect of high light utilization and efficient charge transport. Our work provides a new method for improving photoelectric response by forming type-I heterostructures and for designing high-performance optoelectronic devices for photodetectors and water splitting.

Diffusion-driven formation of Co[formula omitted]O[formula omitted] nanopetals layers for photoelectrochemical degradation of organophosphate pesticides

A new light is shed on the formation mechanism of Co3O4 nanopetals on Si-based photoanodes by thermal oxidation of a deposited metallic film, and on their use for the rapid chemisorption, the photoelectrochemical detection and subsequent removal of harmful fenitrothion (FNT), a commonly used organophosphate pesticide which represents a serious risk to the public health. Using Au clusters as markers for the external surface of the as-deposited film, the results of complementary experiments indicate that the Co3O4 petal formation during oxidizing annealing is related to the non-uniform Co out-diffusion and oxidation rather than to a local melting, as previously suggested. When grown on Si photoanodes under controlled conditions, Co3O4 nanopetals are stable and exhibit high photoelectrocatalytic activity due to the increased active area with respect to the corresponding thin film. These nanostructures work efficiently for FNT sensing (sensitivity of 0.1 μA/(cm2μM)) through the direct coordination of the FNT nitro-groups on the Co(II) centers, that inhibit the Co(II) oxidation. Furthermore, we demonstrate that a low amount of this nanostructured film, polarized at a modest bias (1.45 V vs RHE) and under visible light illumination (100 mW/cm2), can efficiently remove the pesticide in water with a time constant of 1 h without the need for catalyst recollection, and remains stable, thus making it suitable for environmental remediation applications.

Enhancement Strategy of Photoelectrocatalytic Activity of Cobalt-Copper Layer Double Hydroxide toward Methanol Oxidation: Cerium Doping and Modification with Porphyrin.

Designing durable, high-active, and low-cost noble-metal-free photoelectrocatalysts for methanol electrooxidation is highly demanded but remains a challenge. Herein, the photoelectrocatalytic activity of cobalt-copper layer double hydroxide (CoCu-LDH) for methanol oxidation reaction (MOR) in the alkaline media under light was remarkably enhanced by cerium (Ce) doping and further by 5,10,15,20-tetrakis(4-carboxylphenyl)porphyrin (TCPP) modification. TCPP/Ce-CoCu-LDH exhibits a remarkable mass activity of 1788.2 mA mg-1 in 1 mol L-1 KOH with 1 mol L-1 methanol under light, which is 2.3 and 1.8 times higher than that of CoCu-LDH (782.2 mA mg-1) and Ce-CoCu-LDH (987.4 mA mg-1). The UV-vis diffuse reflectance spectra and photoluminescence emission spectra reveal that TCPP/Ce-CoCu-LDH can effectively utilize the visible light and inhibit the electron-hole pairs' recombination because of the introduction of porphyrin. Furthermore, more active sites and the greater electrical conductivity of TCPP/Ce-CoCu-LDH also contributed to the high photoelectrocatalytic activity. Thus, TCPP/Ce-CoCu-LDH can be used as a low-cost alternative for Pt-based catalyst toward MOR.

Conversion of Interfacial Chemical Bonds for Inducing Efficient Photoelectrocatalytic Water Splitting.

Sp-C-hybridized alkyne bonds present the natural advantages of interacting with metal atoms and have the ability to generate a large number of new catalytic active sites on the surface and the interfaces, thus greatly promoting the efficient progress of various light/electrochemical reactions. In this work, we have successfully fabricated a novel type of interfacial structure containing sp-C-Mo/O bonds and mixed Mo valence states with outstanding catalytic activity and stability for photoelectrocatalytic (PEC) overall water splitting in a wide pH range (0-14), due to the presence of sp-carbon-rich graphdiyne. For example, in alkaline conditions (pH = 14), the overpotentials of oxygen and hydrogen evolution reactions at 10 mA cm-2 are 165 and 8 mV. When being used as an electrolyzer, the cell voltage of this catalyst is only 1.40 V to achieve 10 mA cm-2. The high PEC activity of graphdiyne@molybdenum oxide originates from the conversion of chemical bonds at the sp-C hybrid interface and the coexistence of multivalent states of molybdenum, triggering a large number of catalytic active sites, greatly promoting charge transfer and lowering water dissociation energy.

High photoelectrocatalytic activity of selenium (Se) doped TiO2/Ti electrode for degradation of reactive orange 84

Studies on the synthesis of TiO2/Ti doped Se electrode to degrade reactive orange 84 (RO 84) compounds under UV-Visible irradiation have been successfully carried out. The research objective is to obtain the Se-TiO2/Ti electrodes and test performance in degrading RO 84 under irradiation of UV-Visible light by photoelectrochatalytic. Se-TiO2/Ti electrode were prepared by anodizing and dip coating methods. XRD analysis of TiO2/Ti electrode showed the formation of anatase crystals. The surface morphology of the electrode showed the nanotube structure while the composition of the elements in the electrodes was determined by EDX and the presence of selenium was detected at 0.80%. The characteristics of using Linear Sweep Voltammetry (LSV) show that TiO2/Ti electrodes are active in UV light, while Se-TiO2/Ti electrodes are active in visible light. Electrode activity test in degrading RO 84 showed that the Se-TiO2/Ti photoelectrocatalis performance with variations in UV and irradiation of visible light was good in integrating RO 84 with a degradation rate of 98%.

Partial photoelectrocatalytic oxidation of 3-pyridinemethanol by Pt, Au and Pd loaded TiO2 nanotubes on Ti plate

The photoelectrocatalytic (PEC) oxidation of 3-pyridinemethanol to 3-pyridinemethanal and vitamin B3 was investigated by using Pt, Au and Pd loaded (as single or bimetallic) nanotube structured TiO2 on Ti plate in water under UVA irradiation. Nanotube structured TiO2 on Ti plate samples were prepared as anode by anodic oxidation method in ethylene glycol solution in different times, and then they were calcined at 500 °C to be obtained in crystalline form. The anodes were loaded with noble metals by electrochemical reduction method and characterized by XRD, XPS, SEM, and photocurrent techniques. The TiO2 on the plates was in the anatase phase. The loaded metals were in metallic form and heterogeneously dispersed on the TiO2 surface in different sizes. The results indicate that a high amount of metal loading negatively affected the PEC activity of the metal loaded samples because UVA irradiation inside the nanotubes was inhibited by the presence of the metal. On the contrary, low amount of Pd showed high PEC activity and high product selectivity values with respect to the pristine sample. PEC experiments were also more selective than the photocatalytic ones for vitamin B3 production. Electrocatalytic (EC) and photocatalytic (PC) experiments were also conducted, however no or low activity was obtained, respectively. PEC experiments showed to be more selective than the PC ones for vitamin B3 production.

Significantly Enhanced Photoelectrocatalytic Alcohol Oxidation Performance of CdS Nanowire-Supported Pt via the “Bridge” Role of Nitrogen-Doped Graphene Quantum Dots

Environmentally friendly, high energy conversion efficiency, and low pollution emission direct alcohol fuel cells (DAFCs) represent an ideal future clean renewable energy source. Herein, N-doped graphene quantum dots (N-GQDs) are introduced into cadmium sulfide (CdS) nanowires to form a “dot-on-nanowire” structure and support Pt nanoparticles to fabricate the electrode material, which is the core component of fuel cells. With the assistance of visible light irradiation, the as-prepared Pt-CdS/N-GQD electrode displays 2.7, 3.9, and 8.1 times improved electrocatalytic performance on methanol, ethanol, and ethylene glycol oxidation compared to the Pt-CdS one, respectively. Meanwhile, another essential parameter to evaluate the catalytic properties, the long-term stability of the corresponding electrode, is also significantly promoted under visible light illumination. The N-GQDs served as the “bridge” to link the photo- and electrocatalytic processes for facilitating efficacious interfacial charge transfer and the separation of photogenerated electron–hole pairs in the Pt-CdS/N-GQD electrode, which contributes to the synergistic effect of photoelectrocatalysis for the promotion of catalytic efficiency and stability. The present studies provide a promising avenue to design the high photoelectrocatalytic activity and superior poison resistance electrode materials for application in DAFCs.

Hydrothermal deposition of AgCl/AgBr co-sensitizers to modify TiO2 NTs for enhanced photocatalytic performance

AgCl/AgBr co-sensitizers were prepared on TiO2 nanotube arrays (TiO2 NTs/AgCl/AgBr) by the hydrothermal method. The composition, morphology, optical absorption, photoelectric and photoelectrocatalytic (PEC) performances of TiO2 NTs/AgCl/AgBr were influenced by the concentration ratio of KCl/KBr. The investigation results revealed that the TiO2 NTs/AgCl/AgBr photocatalyst exhibited dramatically strong visible light absorption and outstanding photoelectrochemical capacity. The photoelectrode produced high visible light surface photovoltage (-0.43 V), transient photocurrent (0.47 mA/cm2) and carrier concentration (4.39 × 1020 cm-3). The sample also showed high PEC activity in the organic dye and Cr(VI) removal, and the photocatalytic mechanism and charge carrier transfer path were described based on PEC results. The investigation would offer prospective insight to the sensitization of TiO2 NTs, which would result in extensive attraction in the preparation and application of semiconductor materials as photoelectrodes and photocatalysts with superior photoelectrochemical performances.

Fabrication and high photoelectrocatalytic activity of scaly BiOBr nanosheet arrays

Bismuth oxybromide (BiOBr) nanosheet arrays (NSAs) were successfully prepared on the surface of indium tin oxide glass (hydrophilic pretreated) by solvothermal method using [C16mim]Br ionic liquid as bromine source and template. The effects of different reaction temperatures on array synthesis were investigated. BiOBr NSA-160 (NSAs prepared at 160 °C for 8 h) had the best photoelectrocatalytic (PEC) activity. The removal rate of ciprofloxacin hydrochloride by BiOBr NSA-160 was 91.4% by applying a bias voltage of 0.9 V and irradiating under visible light for 180 min. Results of the analyses of the morphology, photoelectric properties, energy band structure, and degradation active species show that BiOBr NSA-160 is a p-type photocatalyst with a thickness of approximately 500 nm, a light response range of less than 440 nm, and photocurrent density of 69 μA/cm2 at the optimal bias voltage is 0.9 V. The high PEC activity of BiOBr NSA-160 was deduced from two aspects: one is that the bias potential effectively improves the separation efficiency of photogenerated carrier, and the other is that the structure of the nanoarray increases light absorption and active sites. BiOBr NSAs are promising PEC material for application in pollutant removal.

Photoelectrocatalytic activity PbO2 loaded highly oriented TiO2 nanotubes arrays

PbO2 loaded TiO2 nanotubes electrode were prepared using electrodeposition and investigated its photoelectrocatalytic activity at the oxidation of aspirin. It indicated that the Ti/TiO2 NTs/PbO2 electrode had high photoelectrocatalytic activity. The results showed that the removal efficiency of aspirin could be reached up to 65% after 2 h photoelectrolysis at Na2SO4 concentration of 0.1 mol·l−1, aspirin initial concentration of 2 g·l−1, the current density of 0.3 A/cm2, electrode spacing of 1 cm. The reaction mechanism of Ti/TiO2 NTs/PbO2 electrodes photoelectrocatalytic oxidation aspirin mainly caused by the OH· radical attacking aspirin molecules with the generation of small linear organic compounds.

Design and construction of a highly efficient photoelectrocatalytic system based on dual-Pd/TNAs photoelectrodes for elimination of triclosan

Promoting the separation efficiency of photogenerated charges plays the crucial part in photoelectrocatalytic (PEC) process, here a high efficient PEC system based on dual-Pd/TNAs photoelectrodes was designed and constructed, in which 99.77% of triclosan could be eliminated with a pH 8, applied voltage 3.0 V and electrolyte concentration 1.0 mol·L−1. Afterwards, the high PEC activity and stability of the PEC system were evaluated by photoelectrochemical (PECH) and hydroxyl radicals (OH) measurements, as well as recycling experiments. Furthermore, the changes of toxicity, possible degradation pathway and mechanism of PEC system were systematically studied. This study provided an innovative dual-photoelectrodes PEC reaction to eliminate refractory pollutants in water and waste water.

3D cross-linked BiOI decorated ZnO/CdS nanorod arrays: A cost-effective hydrogen evolution photoanode with high photoelectrocatalytic activity

ZnO/CdS photoanode with an excellent photoelectrochemical (PEC) performance for water splitting to produce hydrogen, but its practical application is seriously hindered owing to the photocorrosion induced by photoholes on the surface of CdS. Herein, a 3D cross-linked heterostructure ZnO/CdS/BiOI nanorod arrays (NRAs) has been prepared by a simple solvothermal strategy. Under visible light illumination (λ > 420 nm), the ZnO/CdS/BiOI NRAs photoanode shows an excellent PEC activity and generates a photocurrent density of 9.12 mA cm−2 at 1.1 V vs. RHE, which is 1.8 times higher than that of the ZnO/CdS NRAs photoanode in the alkaline electrolyte. Furthermore, the photoanode achieves a high photo conversion efficiency of 3.49% and a long-time stability over 6000 s. It is proposed that the BiOI nanosheets not only serve as protecting layer to restrain the photocorrosion of CdS, but also facilitate the charge separation in CdS by the virtue of the p-n junction formed between CdS and BiOI.

Photoelectrocatalytic degradation of methylene blue on cadmium sulfide–sensitized titanium dioxide film

Herein, cadmium sulfide–sensitized titanium dioxide (CdS/TiO2) deposited on a fluoride-doped tin oxide electrode is proposed for achieving the photoelectrocatalytic (PEC) degradation of methylene blue (MB). Under optimum conditions (six accumulative CdS depositions, 3.0-V DC applied biased potential, and 300-W Xe arc lamp irradiation), the prepared CdS/TiO2 films exhibited the highest PEC degradation of MB (82 ± 3%) compared with photocatalytic (70 ± 5%) or electrocatalytic (39 ± 5%) degradation. In addition, the higher current density (0.08425 mA/cm2) and the lower charge transfer resistance (78.5 Ω) of 6-CdS/TiO2 film were observed. These were attributable to the strong visible light absorption of CdS, the high charge separation efficiency in the CdS/TiO2 heterostructure, and the low electron–hole recombination rate from the applied biased potential. The feasibility of 6-CdS/TiO2 film was evaluated by the MB degradation in environmental water samples, which demonstrated a high PEC activity (71 ± 3% degradation) of CdS/TiO2 film.

Conformal and Continuous Deposition of Bifunctional Cobalt Phosphide Layers on p-Silicon Photocathodes for Improved Solar Hydrogen Evolution

p-Silicon (Si) has been extensively investigated in recent years as a promising photocathode for solar-driven hydrogen evolution. However, it remains challenging to fabricate Si photocathodes having both high photoelectrocatalytic activity and long-term operational stability through a simple and affordable approach. Herein, we report conformal and continuous deposition of a di-cobalt phosphide (Co2P) layer on lithography-patterned highly-ordered Si nanowire (SiNW) arrays via a cost-effective drop-casting method followed by a low-temperature phosphorization treatment [1]. The as-deposited Co2P layer consists of crystalline nanoparticles and has an intimate contact with SiNWs, forming a well-defined SiNW@Co2P core/shell nanostructure. The conformal and continuous Co2P layer endows dual functions: on the one hand, it serves as a highly-efficient catalyst capable of substantially improving the photoelectrocatalytic activity towards the hydrogen evolution reaction (HER); on the other hand, it can effectively passivate SiNWs to protect them from photo-oxidation, thus prolonging the lifetime of the electrode. As a consequence, when used for solar-driven hydrogen evolution, the SiNW@Co2P photocathode with an optimized Co2P layer thickness exhibits a high photocurrent density of -21.9 mA cm-2 at 0 V versus reversible hydrogen electrode (RHE) and excellent operational stability of up to 20 hours, outperforming many nanostructured silicon photocathodes reported in the literature. Furthermore, we fabricate inverted pyramid textured Si (SiIP) photocathodes coated with a conformal and continuous layer of Co2P [2], which show a photocurrent density as high as -35 mA cm-2 and can constantly split water up to 150 hours without obvious degradation. The combination of passivation and catalytic functions in a single continuous layer represents a promising strategy for designing high-performance semiconductor photoelectrodes for use in solar-driven water splitting, which may simplify the fabrication procedures and potentially reduce the production cost. Acknowledgement This work was funded by ERDF funds through the Portuguese Operational Programme for Competitiveness and Internationalization COMPETE 2020, and national funds through FCT – The Portuguese Foundation for Science and Technology, under the project “PTDC/CTM-ENE/2349/2014” (Grant Agreement No. 016660). The work is also partially funded by the Portugal-China Bilateral Collaborative Programme (FCT/21102/28/12/2016/S).

Simple Fabrication of SnO2 Quantum-dot-modified TiO2 Nanorod Arrays with High Photoelectrocatalytic Activity for Overall Water Splitting.

Photoelectrochemical (PEC) water splitting has been demonstrated as a promising way to acquire clean hydrogen energy. However, the efficiency has been limited by the high recombination rate of photogenerated electron-hole pairs. Herein, we provided a simple approach to construct a novel SnO2 quantum dots (QDs) modified TiO2 nanorod arrays (NAs) by the calcination of SnCl2 -adsorbed TiO2 NAs. The photocurrent density of SnO2 QDs/TiO2 NAs exhibits about 5 times higher than that of parent TiO2 NAs at a bias of 0.4 V vs. Ag/AgCl. SnO2 QDs/TiO2 NAs also show a high photoelectrocatalytic activity for overall water splitting with an actual yield of H2 and O2 to be 27.85 and 11.87 μmol cm-2 h-1 , respectively. The excellent performance of photoanode for PEC water splitting could be attributed to its Z-scheme heterostructure for good separation efficiency and transport rate of photogenerated charge carries.

Photoelectrocatalytic oxidation of ascorbate promoted by glucose and tris-(hydroxylmethyl)-amino methane on cadmium sulfide/titanium dioxide electrodes for efficient visible light-enhanced fuel cells

Glucose (GLU) and tris-(hydroxylmethyl)-amino methane (Tris) have been introduced to promote the photoelectrocatalytic oxidation of ascorbate (AA) on binary CdS-TiO2 nanoparticle-modified electrodes for efficient photoelectrochemical fuel cells. The oxidative peak height of AA shows an increase with the rise of AA, GLU, OH− or Tris concentration under dark or visible light irradiation conditions. The photoelectrocatalytic activities of TiO2 nanoparticles are dependent on the calcination temperature ranged between 250 and 850 °C. The TiO2-450 generated from the calcination treatment at 450 °C is combined with CdS nanoparticles to achieve a CdS/TiO2-450 electrode with high photoelectrocatalytic activity towards the oxidation of AA and GLU, for which the oxidation mechanism is discussed. While employing CdS/TiO2-450 as anode, carbon felt (CF) as cathode, 0.1 mol L−1 AA-0.1 mol L−1 GLU as fuels, Na2SO3-Na2S as sulfur-containing sacrificial agents, and 60 mL min−1 O2 as oxidant, the visible light-assisted fuel cell shows synergistically enhanced performances. The open-circuit photovoltage (VOC) and short-circuit photocurrent density (ISC) are 0.813 V and 0.568 mA cm−2, and the maximum power density (Pmax) is 35.56 μW cm−2 upon visible light irradiation of 0.18 mW cm−2. The present results provide an interesting platform for the effective utilization of renewable energy sources.

A honeycomb multilevel structure Bi2O3 with highly efficient catalytic activity driven by bias voltage and oxygen defect

In this work, we report a bismuth oxide film electrode with oxygen defects and honeycomb multilevel structure prepared by one-step hydrothermal method. The control of raw materials enables to control the thickness and morphology of BiO electrodes. The photoelectrocatalytic of prepared electrodes were tested in various conditions. Under visible light irradiation (λ ≥ 420 nm) and 3 V bias, the sample BiO-2 has the highest photoelectrocatalytic activity, which is 4.95 times higher than the photocatalytic activity and 9.86 times higher than the electrocatalytic activity. The oxygen defects of bismuth oxide were confirmed by EPR and DFT calculation. The morphology and structure of prepared samples were tested by XRD, scanning electronic microscope (SEM), high-resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectroscopy (XPS). The enhanced photoelectrocatalytic activity is attributed to the proper bias voltage, oxygen defects, and honeycomb multilevel structure. The results of tapping experiments showed that the main active species during the photoelectrocatalytic progress is superoxide radical and the mechanism of the photoelectrocatalysis was proposed.