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\"This comprehensive practitioner guide presents CP theory to industry recognised codes for basic and advanced applications to metals, with an outline of subsea coating systems. It covers retrofitting and for internal applications, along with computational modelling, and the management of offshore CP systems\"-- Provided by publisher.

This paper introduces an innovative improvement to impressed current cathodic protection (ICCP) systems by integrating a pulse-feeding technique designed to address metal protection degradation during off-potential periods, a common issue in conventional systems. The proposed system enhances the overall effectiveness and reliability of ICCP, providing consistent corrosion protection for critical metal structures. A notable advantage of this method is its simplicity, utilizing a cost-effective microcontroller for pulse feeding. This approach simplifies integration processes and enhances cost-effectiveness, making it an attractive solution for improving cathodic protection system performance without substantial additional costs. The method addresses conventional ICCP weaknesses by applying a high-frequency pulse current during off-potential periods. This reduces excessive negative charge buildup on metal surfaces during interruptions, boosting the system’s effectiveness and stability. Research laboratory experiments were conducted using pulse width modulation (PWM) on an ATmega328P microcontroller to demonstrate the method’s effectiveness. Additionally, an IoT-monitored ICCP system was developed using an ESP32 microcontroller and the Blynk application. Results highlight the superiority of a 50 kHz pulse feeding frequency in preventing corrosion compared to lower frequencies. Overall, this advancement significantly enhances ICCP systems, providing improved corrosion protection and durability in harsh environments.

Corrosion is a phenomenon that occurs on pipes, reinforced concrete structures, and storage tanks and causes a major impact on the facility structures and can have a major impact on a facility’s structural integrity. This can result in a serious failure in the system and lead to substantial economic losses. One of the solutions widely used to eliminate the corrosion effects is by applying cathodic protection, which depends on direct current as the supply potential. The technique of cathodic protection is used to control corrosion in the utilisation of reinforced concrete structures, pipelines, storage tanks, etc. A photovoltaic cathodic protection system is normally used as an energy source to supply the system. This research reviews the technique utilised for applying solar photovoltaics in powering systems of cathodic protection. Subsequently, it highlights the methods of cathodic protection systems, sacrificial anode cathodic protection and the impressed current cathodic protection. Finally, it is indicated that applying solar photovoltaics in powering cathodic protection systems has great efficacy in controlling the corrosion in the facility’s equipment in a smarter, controlled way. Furthermore, this study provides significant insight into the designing and operating the domain of solar photovoltaic systems that power cathode protection systems.

In the marine environment, steel materials usually encounter serious problems with chemical or electrochemical corrosion and fouling by proteins, bacteria, and other marine organisms. In this work, a green bifunctional Z-scheme CuOx/Ag/P25 heterostructure coating material was designed to achieve the coordination of corrosion prevention and antifouling by matching the redox potential of the reactive oxygen species and the corrosion potential of 304SS. When CuOx/Ag/P25 heterostructure was coupled with the protected metal, the open circuit potential under illumination negatively shifted about 240 mV (vs. Ag/AgCl) and the photoinduced current density reached 16.6 μA cm−2. At the same time, more reactive oxygen species were produced by the Z-shape structure, and then the photocatalytic sterilization effect was stronger. Combined with the chemical sterilization of Ag and the oxide of Cu, the bacterial survival rate of CuOx/Ag/P25 was low (0.006%) compared with the blank sample. This design provides a strategy for developing green dual-functional coating materials with photoelectrochemical anticorrosion and antifouling properties.

Thermoelectric cement‐based composites integrate thermoelectric effects with structural capabilities, presenting an effective solution for harvesting environmental heat in self‐powered cathodic protection. While the prospects are promising, their performance has been constrained by the compatibility between functional fillers and cementitious materials. This study demonstrates that PEDOT: PSS(PP) significantly improves the dispersion of multi‐walled carbon nanotube (CNT) and Bi0.5Sb1.5Te3 (BST) in cementitious materials. The optimized composite(0.2 wt.% CNT, 1.0 vol% PP, and 1.0 wt.% BST) exhibits a 28.4% increase in conductivity and a 15.9% reduction in thermal conductivity compared to the control. Additionally, it achieves an impressive Seebeck coefficient of 450 µV K−1. Importantly, the composite maintains superior compressive strength (> 40 MPa) and chloride penetration resistance (< 7 × 10−12 m2 s−1), with over 80% property retention after 60 days under extreme temperatures of −20 or 70 °C. A thermoelectric generator (TEG) is assembled by connecting 30 specimens in series to form a 10 × 10 cm2 device. The TEG exhibits less than 8% voltage decay during 20 h of continuous operation and successfully powered an LED. The TEG also substantially mitigates steel corrosion in self‐powered cathodic protection, reducing corrosion current density and corrosion rate by more than 47%. In this study, PP and BST are used to synergistically enhance the dispersibility and thermoelectric performance of CNT cementitious materials. Further Author Manuscript research shows that the composite material maintains >80% compressive strength and chloride resistance performance at −20 or 70°C. A TEG assembled from 30 series‐connected specimens successfully powers a commercial LED and achieves a power supply for steel cathodic protection.

Developing solar energy conversion strategies is crucial to overcome stainless steel corrosion protection challenges. Through the chemical bath deposition (CBD) technique, zinc and cobalt nanoparticles were deposited onto TiO 2 nanotubes (TNTs) to use as photoanodes in the photoelectrochemical cathodic protection (PECP) of AISI 304 stainless steel. The composition of the chemical bath affected the structure and properties of the deposited TNT layers, which were analyzed using field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy. Considering both illuminated and dark conditions, the photocathodic protection performance of the composite film was evaluated in a 3.5 wt% NaCl solution. The Co 3 O 4 –ZnO/TNT photoanodes demonstrated enhanced light absorption, charge separation, and improvement of photoelectrochemical properties, attributed to the synergistic effect of the ternary system, n–p junction formation at the Co 3 O 4 –ZnO interface, and TiO 2 –ZnO heterojunction. The optimal photoanode achieved a 1.6% higher photocurrent density than the original TNT photoelectrode. Moreover, the Co 3 O 4 –ZnO/TNT photoanodes demonstrated corrosion protection for stainless steel by exhibiting a negative shift in corrosion potential of the steel (− 614 mV vs. Ag/AgCl for the optimal photoanode) following light exposure and showing delayed cathodic protection when the light was turned off. This study suggests that Co 3 O 4 –ZnO/TNTs have a promising potential for use in photocathodic protection. It also highlights how the photoelectrochemical properties of deposited layers are affected by the chemical bath composition.

Microbiologically influenced corrosion (MIC) is one of the key causes of material failure in marine engineering, and sulfate-reducing bacteria (SRB) and iron-oxidizing bacteria (IOB) are typical representatives of anaerobic and aerobic microorganisms, respectively. These microorganisms are widely present in marine environments and can form synergistic communities on the surface of metal materials, posing a corrosion threat to them. At the same time, the presence of mixed bacteria may have an effect on cathodic protection, so this study investigates the growth metabolism of mixed SRB and IOB under different cathodic protection potentials in an impressed current cathodic protection (ICCP) system in a marine environment containing SRB and IOB. It also examines the attachment of these microorganisms to the anode and cathode, and the impact on cathodic protection efficiency. The results indicate that in a marine environment containing IOB and SRB, the cathodic protection efficiency of the ICCP system increases with the negative shift of the protection potential. A more positive cathodic protection potential promotes the adhesion of mixed bacteria on the electrode surface and the formation of a biofilm, which reduces cathodic protection efficiency. In contrast, at a cathodic protection potential of −1.05 V (SCE), bacterial growth is inhibited, and a dense crystalline corrosion film primarily composed of Fe2O3 and Fe(OH)3 forms on the cathode surface. This film effectively protects the cathodic metal, significantly mitigating MIC.

The permanent presence of metallic pipelines in the soil produces electrochemical reactions, which leads to the corrosion activity and thus, an adequate cathodic protection strategy is required. The purpose of this paper is to assess the effect of inductive coupling between an EHV overhead power line and a buried metallic pipeline in normal operation; and to optimize a sacrificial anode cathodic protection system from corrosion evolution using a new efficient meta-heuristic algorithm of Teaching Learning Based Optimization (TLBO). The results obtained indicate that the induced voltage resulting from the inductive coupling exceeds the limit recommended by the majority of international standards; the calculated value of corrosion current density presents a relevant parameter having a significant effect on the corrosion rate and metal loss. Therefore; the selected optimization algorithm proves to be accurate in determining the parameters associated with the design of the sacrificial anode cathodic protection system and is able to meet the current requirement criterion necessary for the protection implemented and to ensure the stability and optimal performance of the hydrocarbon transportation pipeline system.

Photochemical cathodic protection represents a burgeoning, eco-friendly, and pollution-free technology for metal preservation. Strontium titanate (SrTiO3), a semiconductor material distinguished by its unique band structure, is particularly well suited for applications in photoelectrochemical cathodic protection. Addressing its limitations through the strategic doping of two nonmetal elements can significantly enhance its photoelectrochemical attributes. In this study, a flower-ball morphology of SrTiO3 was synthesized via a hydrothermal process. The material was subsequently co-doped with nitrogen and fluorine, sourced from ammonium chloride and sodium fluoride, respectively. This co-doping process was applied to protect 304 stainless steel under a simulated sunlight environment with N/F-x%-SrTiO3. The outcomes of the experiment demonstrated the successful incorporation of N and F into the SrTiO3 crystal lattice. The photoanode composed of SrTiO3 doped with 2% F and 3% N exhibited superior photochemical cathodic protection capabilities. It achieved a photocurrent density of 6.0 μA/cm2, and the open-circuit potential shifted negatively to −0.46 V. The co-doping modification with N and F facilitated the formation of impurity energy levels within the bandgap of SrTiO3. This intervention effectively reduced the semiconductor's bandgap width, thereby increasing the material's sunlight utilization efficiency and bolstering its photochemical cathodic protection performance. This advancement marks a significant stride in the development of SrTiO3 for applications in metal protection and environmental sustainability.The application of co-doping techniques significantly enhances the photochemical cathodic protection properties of SrTiO3. By introducing nitrogen (N) and fluorine (F) into the SrTiO3 lattice, a novel impurity level is created just above the native valence band. The presence of this impurity level effectively narrows the bandgap of SrTiO3, leading to an increased absorption of sunlight and a consequent improvement in the utilization of solar energy. Under identical experimental conditions, the photocurrent density of the co-doped SrTiO3 achieves a remarkable 6 μA/cm2, which is a threefold increase compared to that of the undoped SrTiO3. Furthermore, the open-circuit potential of the doped material exhibits a more negative shift, reaching −0.46 V, a significant improvement of 60 mV over the pure SrTiO3. These enhancements underscore the effectiveness of the co-doping strategy in optimizing the material's performance for photochemical cathodic protection applications.

In this study, the cathodic activity of biofilmed stainless steel surfaces was investigated at two exposure depths at the same location at 1,020 m and 2,020 m depth. For this purpose, a set of passive materials and sensors were exposed for 11 months in Azores, in the Atlantic Ocean. Characteristic cathodic depolarizations due to biological activity were observed in intermediary and deep water. However, a strong cathodic activity was only measured in deep water. Potential ennoblement appeared between 80 d and 200 d, depending on the exposure depth and the experimental setup used. In a given environment, the biological cathodic activity appears to be strongly related to the limiting parameter of the reaction, which can be anodic or cathodic. The biofilm sensors exposed for the first time in open, deep water appear relevant to discriminate cathodically “strongly-active” and “weakly-active” biological activity. Under cathodic control, a high current density was measured on stainless steel in deep seawater. The experimental setup used is particularly relevant as it allows determination in situ of the maximal cathodic current density.