Photoelectrochemical Cathodic Protection Performance Research Articles

NiCo-layered double hydroxide modified TiO2 nanotube arrays and its application in photoelectrochemical cathodic protection of 304 stainless steel

NiCo-layered double hydroxide (NiCo-LDH) modified TiO2 (NiCo/TiO2) were prepared by a simple electrochemical deposition method. The morphology, chemical composition, light adsorption and photoelectrochemical (PEC) properties of these composites were fully characterized. The performance of NiCo/TiO2 in PEC cathodic protection of 304 stainless steel (304 SS) was investigated in NaCl solution. The results showed that NiCo(−0.8)/TiO2 had the best PEC cathodic protection performance, as indicated by the largest photo-induced potential drop (−440 mV) of 304 SS. It was proposed that a type II heterojunction was built between NiCo-LDH and TiO2, leading to a more efficient separation of photo-generated charge carriers.

Confinement assembly of a novel Nb2O5&ZnIn2S4 photoanode and its highly efficient and sensitive photoelectrochemical cathodic protection performance

Constructing a metal-oxides based type Ⅱ heterojunction owning both controllable topography and well matched energy band remains urgent for photoelectrochemical cathodic protection technology. In this work, we designed a desert flower-like Nb2O5&ZnIn2S4 photoanode via a synergistic confinement assembly strategy (structural confinement and electronic confinement) for in situ photoelectrochemical cathodic protection of carbon steel in marine environments. Metal oxides with spherical morphologies were obtained by tuning the crystal plane orientation and nuclei growth, which defines the structural region for the in situ assembly of ZnIn2S4. Compared with TiO2&ZnIn2S4 system, the Nb2O5&ZnIn2S4 system exhibits stronger photoelectric conversion efficiency and photoelectron reduction ability due to its more matched energy bands. The structural confinement facilitates the exposure of reactive sites, and electronic confinement significantly improves the redox activity of type Ⅱ heterojunction, thereby realizing a high efficiency (protection potential is as low as −0.69 V) and high sensitivity (performance retention rate after 200 cycles is as high as 92%) photoelectrochemical cathodic protection for carbon steel in marine environment (without hole scavenging agent).

Influence of Heat Treatment on the Photoelectrochemical Cathodic Protection Performance for SrTiO3 Films

Influence of Heat Treatment on the Photoelectrochemical Cathodic Protection Performance for SrTiO3 Films

Morphology effects of in situ hydrothermally treated hierarchical TiO2 nanofilms on their photoelectrochemical cathodic protection performance against 304 stainless steel corrosion

Morphology effects of in situ hydrothermally treated hierarchical TiO2 nanofilms on their photoelectrochemical cathodic protection performance against 304 stainless steel corrosion

Enhancing photoelectrochemical cathodic protection performance by facile tuning sulfur redox state in sacrificial agents

Photocathodic protection (PCP) performance is restricted by the photogenerated charges separation efficiency. This study reported a facile approach to enhance PCP performance. Na2S, Na2SO3, Na2S2O3, Na2SO4, and NaCl was selected as sacrificial agents, in which the PCP performance is characterized by coupling TiO2 and TiO2/ZnSe composites with 304 stainless steel. TiO2/ZnSe photoanode presented the best PCP performance in Na2S media. The maximum potential drop is 466.7 mV, which is about 3.5 times higher than that of in NaCl media. The corresponding photocurrent density is 270.7 μA/cm2, which is about 10 times higher than that of in NaCl media. Based on circle voltammetry and ultraviolet photo-electron spectroscopy characterization, it was found that the redox potential of the sacrificial reagent governs the migration and consumption of photogenerated holes of the photoanode.

Controlled synthesis of various SrTiO3 morphologies and their effects on photoelectrochemical cathodic protection performance

As an n-type semiconductor with typical perovskite structure, SrTiO3 has broad research prospects in photochemical cathodic protection because of its suitable energy band structure. However, there is a lack of research on the effect of SrTiO3 micro morphology on Photoelectrochemical cathodic protection performance. In this paper, a series of SrTiO3 samples with controllable morphology were designed and prepared by changing the ratio of alcohol to water in the solvent, including nanoparticles (NPs), nano ball (NBs), nano rod (NRs), coral stone-like microspheres (CSLMs) and flower-like microspheres (FLMs). The experimental results show that FLMs samples have better photochemical cathodic protection performance. Under the condition of on light, the photocurrent density of FLMs samples reaches 9.2 μA. The photocurrent density of NPs samples is only 2.5 μA. The former is about 3.6 times that of the latter. The open circuit potential of FLMs samples has shifted from −0.18 V to −0.42 V, with a negative shift of 240 mV, while CSLMs samples have only a negative shift of 180 mV. In contrast, FLMs samples have a more negative shift of 60 mV. After four light cycle experiments, the performance of FLMs samples is stable without obvious change.

Interfacial Schottky junction of Ti3C2Tx MXene/g-C3N4 for promoting spatial charge separation in photoelectrochemical cathodic protection of steel

Photoelectrochemical (PEC) cathodic protection was an ecofriendly and promising method for anti-corrosion of metal. In this work, the Ti3C2 MXene-based photoanode was the first time to apply in the PEC anti-corrosion process. The interfacial Schottky junction in TC-x/CN composites was designed by the electrostatic self-assembly method. Different content of Ti3C2 was to investigate the effect on the PEC performance in TC-x/CN composites. Specifically, the TC-1.0/CN showed the highest PEC cathodic protection performance for 304 SS, which revealed low content of Ti3C2 was beneficial for spatial charge separation. Various characterization techniques analysis further verified the Schottky junction successfully formed at the interface between Ti3C2 and g-C3N4 and significantly promote the spatial charge separation. Furthermore, this work proposed the possible electron transfer pathway and deepened understanding of the PEC cathodic protection mechanism.

Improved Photoelectrochemical Cathodic Protection Performance of Innovative Srtio3/G-C3n4 Composite for 304 Stainless Steel Under Visible Light

Improved Photoelectrochemical Cathodic Protection Performance of Innovative Srtio3/G-C3n4 Composite for 304 Stainless Steel Under Visible Light

Enhancing Photoelectrochemical Cathodic Protection Performance by Facile Tuning Sulfur Redox State in Sacrificial Agents

Enhancing Photoelectrochemical Cathodic Protection Performance by Facile Tuning Sulfur Redox State in Sacrificial Agents

Novel K-doped TiO2 nanotube arrays with superhydrophilic surface and high photoelectrochemical cathodic protection

K-doped TiO2 nanotube arrays with superhydrophilicity and high photoelectrochemical cathodic protection performance were prepared via simple anodization and hydrothermal method. The high photoelectroactivity and high photoelectrochemical cathodic protection performance were proven on the basis of photoinduced I–V curves, Mott–Schottky plots, and open circuit potential of coupling electrode. The mechanism of high photoelectrochemical cathodic protection performance was verified on the basis of ultraviolet–visible spectroscopy diffused reflectance spectra, ultraviolet photoelectron spectroscopy, and contact angle.

Co-sensitization of TiO2 nanotube arrays with polymerized aromatic amines and its application in photoelectrochemical cathodic protection

In this work, an initiator-free polymerization of 4,4′-diaminobiphenyl (DABP) happened on the TiO2 nanotube arrays (TNT/Ti) via a facile in-situ solvothermal synthesis method. The poly-4,4′-diaminobiphenyl (PDABP) modified TNT/Ti (PDABP/TNT/Ti) composite was fully characterized by SEM, XRD, FTIR, and XPS. The prepared PDABP/TNT/Ti exhibited stronger visible light absorption, improved separation of photogenerated charge carriers, reduced charge transfer resistance at the interface, and enhanced reducing capability of photoelectrons (as indicated by the more negative energy level of the conduction band, ECB). Attributed to the formation of the type II heterostructure between TiO2 and PDABP, the PDABP/TNT/Ti showed enhanced photoelectrochemical (PEC) cathodic performance by polarizing the potential of 304 stainless steel (304SS) to ∼−900 mV in a 3.5 wt% NaCl. By replacing monomers, the strategy of enhancing the PEC cathodic protection performance of TNT/Ti using electrically conducting polymers of aromatic amines was confirmed to be simple and effective.

Ingenious preparation of “layered-closed” TiO2-BiVO4-CdS film and its highly stable and sensitive photoelectrochemical cathodic protection performance

Constructing a photo-anode owning both protection performance and high stability remains urgent for photoelectrochemical cathodic protection technology. In this work, we develop a “layered-closed” heterojunction (m-TiO2-f-BiVO4-c-CdS) with a well-matched energy band. The closed structure benefits to avoid the loss of active materials, and the layered structure with a well-matched energy band promotes the orderly separation of electrons and holes, thereby achieving a highly stable and sensitive photoelectrochemical protection performance in 3.5 wt% NaCl without hole scavenging agent (performance retention rates after 100 cycles and 3.3 h are as high as 86% and 80%, respectively).

Preparation of FeS2/TiO2 nanocomposite films and study on the performance of photoelectrochemistry cathodic protection

FeS2/TiO2 nanotube array composite films with clean, high efficiency, low cost and low consumption were prepared by electrochemical anodization and hydrothermal methods. The modification of FeS2 nanoparticles on the surface of TiO2 nanotube array film not only broadens the light absorption range of TiO2, but also improves the utilization ratio of visible light and the separation rate of photogenerated electron–hole pairs, which greatly improves the photoelectrochemical cathodic protection performance of TiO2 for 304 stainless steel (304SS). Under visible light irradiation, the open circuit potential of 304SS coupled with the FeS2/TiO2 nanocomposite films decreased from − 170 to − 700 mV, and the electrode potential can still maintained at − 400 mV after the light was turned off. Compared with pure TiO2 nanotube array film, FeS2/TiO2 nanocomposite film has better photoelectrochemical cathodic protection effect on 304SS in 3.5 wt% NaCl corrosion medium.

Effect of nanoscale graphene oxide on the sustained photoelectrochemical cathodic protection performance of the WO3 nanothorn clusters

The novel photoelectrochemical cathodic protection technology is actively researched and developed for alleviating severe corrosion of marine metallic materials. And the corresponding sustained photoelectrochemical cathodic protection in the dark, under the collaboration of the electron storage materials, is also developed and optimized. WO3, as a kind of electron storage material, shows great potential in this area. The WO3/graphene oxide (WO3/GO) nanothorn cluster composites were synthesized via solovthermal method. The nanoscale graphene oxide (GO) sheets, added as templates, result in the formation of WO3 nanothorn clusters in the WO3/GO composite. The hybrid structure of the WO3/GO composite was formed when the GO adding amount is 0.2 wt%, denoted as WO3/GO 0.2. The lattice of WO3 contracted slightly and the crystallinity of WO3 was enhanced. The WO3/GO 0.2 nanothorn cluster composites promote the transfer and storage efficiency of the electrons compared with pure WO3. The high conductivity of the partly reduced GO leads to a faster electron transfer in the WO3/GO composite. The sustained photoelectrochemical cathodic protection performance of the WO3/GO composite under the assistance of TiO2 (i.e., the coupling of WO3/GO 0.2-TiO2) for 304 stainless steel (SS) was promoted. A larger number of photoinduced electrons, generated by TiO2 under white light illumination, can be stored in the WO3/GO composite and be transferred to the coupled 304 SS electrode after shutting off the light. WO3/GO composite exhibits enhanced sustained photoelectrochemical cathodic protection performance for 304 stainless steel under the assistance of TiO2.

Efficient TiO2/AgInS2/ZnS Nanoarchitecture Photoelectrode for the Photoelectrochemical Cathodic Protection of Copper in NaCl Solution

An environmentally friendly AgInS2/ZnS nanoparticles (NPs) co-sensitized TiO2 ultrafine branched nanolawn photoelectrode was constructed by depositing AgInS2 sensitizer and ZnS passivator on TiO2 ultrafine nanostructure. This architecture significantly improved the photoelectrochemical conversion efficiency and photoelectrochemical cathodic protection performance for pure copper with a more negative self-corrosion potential under simulated sunlight illumination and in NaCl solution containing no additional hole scavengers. Compared with single AgInS2 NPs sensitized TiO2, the design of ZnS passivation layer on TiO2/AgInS2 significantly improves the charge generation and separation efficiency, and promotes the consumption of the photogenerated holes. The three-dimensional TiO2 with porous ultrafine nanobranched structure possesses high-speed electron transmission pathways and facilitates the rapid collection and migration of the photogenerated electrons. Since the conduction band potentials of AgInS2 and ZnS are more negative, the photogenerated electrons generated by TiO2/AgInS2/ZnS will be maintained at a more negative quasi-Fermi level. This ensures that the photogenerated electrons can be transferred to pure copper. The present work provides new ideas for designing nanoheterojunction materials for the protection of pure copper and other metallic materials with more negative self-corrosion potentials exposed in marine environment under simulated sunlight illumination.

Covalent Organic Framework Decorated TiO2 Nanotube Arrays for Photoelectrochemical Cathodic Protection of Steel

For the first time, a covalent organic framework TpBD was grown in situ on TiO2 nanotube arrays (NTAs), and the performance of the composite was investigated for the application of photoelectrochemical (PEC) cathodic protection. The synthesized TpBD/TiO2 NTA composite exhibited enhanced PEC cathodic protection performance under visible light. Coupled with the TpBD/TiO2 NTA photoanode, the photoinduced potential drop values for 304 stainless steel and Q235 carbon steel in 3.5 wt% NaCl solution were 910 and 370 mV, respectively. It was proposed that the enhanced PEC performance was due to the formation of a Z-scheme heterojunction between TpBD and TiO2.

High-efficiency photoelectrochemical cathodic protection performance of the iron-nitrogen-sulfur-doped TiO2 nanotube as new efficient photoanodes

Novel iron-nitrogen-sulfur-tridoped titanium dioxide nanotubes (Fe-N-S-TiO2 NTs) have been synthesized via single step anodization of titanium using potassium ferricyanide, as a suitable additive, in dimethyl sulfoxide (DMSO) electrolyte and applied as photoanodes in the photocathodic protection of stainless steel 403 (SS403). Photocurrent density, open circuit potential and Tafel polarization curves have been used to study the photocathodic protection effect of the samples prepared. Upon the addition of potassium ferricyanide to the anodizing electrolyte and titanium dioxide nanotube doping, the light absorption of the Fe-N-S-TiO2 NTs were increased to the visible region, comparable with pure TiO2 NTs, according to the results obtained. Enhanced photoelectro-response activity and photocathodic protection performance for 403 stainless steel are exhibited by Fe-N-S-TiO2 NTs under light illumination. In addition, the optimal sample electrode (FT4) potentials shifted negatively to −683 mV under illumination.

High-efficiency photoelectrochemical cathodic protection performance of the TiO2/AgInSe2/In2Se3 multijunction nanosheet array

Optimization of multijunction photoelectric conversion materials with a much negative band potential is very important for improving the photoelectric conversion and photoelectrochemical cathodic protection performance because the well-matched multijunction can assist the fast transport of photogenerated electrons. In this paper, a “green” AgInSe2/In2Se3 sensitized TiO2 nanosheet array (NSA) photoanode was prepared. Vertically-grown two-dimensional TiO2 NSA with the multijunction of TiO2 NSA/AgInSe2(7)/In2Se3(3) improves the separation efficiency and the transfer of photoinduced charge carriers compared with single AgInSe2 sensitized TiO2 NSA. The TiO2 NSA/AgInSe2/In2Se3 photoanode achieves highly efficient photoelectrochemical cathodic protection performance for 316LSS in NaCl solution under AM1.5 light illumination.

Photoelectrochemical cathodic protection of Cu2O/TiO2 p-n heterojunction under visible light

The Cu2O/TiO2 p-n heterojunction composite photoelectrodes were prepared by depositing Cu2O nanoparticles on the surface of TiO2 nanotubes via anodic oxidation and constant current deposition. Field emission scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analyses showed that Cu2O nanoparticles not only deposited on the surface of TiO2 nanotube array, but also on the wall of TiO2 nanotubes. The Cu2O deposition amount could be adjusted by changing the deposition time. The photoelectrochemical cathodic protection (PECCP) performance of the prepared photoelectrodes for 316L stainless steel (SS) was tested under visible light. The constant current deposition time had a significant effect on the PECCP performance of Cu2O/TiO2-X photoelectrodes and Cu2O/TiO2-20 had the best PECCP performance for the coupled 316L SS. This was attributed to the appropriate amount and thickness of Cu2O to form p-n heterojunctions with TiO2, in which separation of the photogenerated carriers was accelerated and transfer of the photogenerated electrons to 316L SS for PECCP was facilitated.

Fabrication of 1D/2D p-g-C3N4@RGO heterostructures with superior visible-light photoelectrochemical cathodic protection performance

A novel photoelectrode system based on one-dimensional g-C3N4 porous nanofibers (1D-p-g-C3N4) heterostructured with 2D-RGO was fabricated by hydrogen bonding self-assembly technology in combination with heat treatment and electrodeposition process. Ascribed to the one-dimensional porous morphology of g-C3N4 and its heterojunction with RGO, the separation efficiency of the photoinduced electrons and holes was dramatically enhanced, leading to its superior PEC cathodic protection performance for 304 stainless steel. Under visible light illumination, the 1D/2D p-g-C3N4@RGO photoelectrode exhibited a photoinduced current density of 10.1 μA cm−2 and a photoinduced polarized potential of − 480 mV, which is 6 and 2.5 times that of g-C3N4, respectively.