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• PEDOT:PSS was adopted to modify the PICP performance of ZnO. • ZnO/PEDOT:PSS shows larger photocurrent and more positive photopotential. • PEDOT:PSS promotes the PICP performance for Cu but reduces that for 316L SS. • Tafel plots of metal and semiconductor material were intersected to clarify the PICP results. • The synergistic mechanism of semiconductor material and metals on the PICP are revealed. Photoinduced cathodic protection (PICP) performance of a semiconductor is closely related to its photoelectric conversion performance. However, this relationship is not clear up to date. In this work, PEDOT:PSS was added during the preparation process of ZnO electrode, endowing the obtained ZnO/PEDOT:PSS electrode with enhanced charge transfer and positive shifted Fermi level. Compared with ZnO, the ZnO/PEDOT:PSS shows larger photocurrent and more positive photopotential, which have opposite effects on the final PICP performance. Thus, the effect of photocurrent and photopotential on the PICP performance can be separately investigated in this paper. ZnO/PEDOT:PSS shows increased PICP performance for Cu but reduced PICP performance for 316L SS. These disparate PICP results were further revealed by the comparison of the photoinduced Tafel plots of semiconductors and the Tafel plots of the protected metals for the first time. And the synergistic mechanism of the photoelectric conversion property of semiconductors and the corrosion rates of the metals are finally clarified. Furthermore, a series ZnO photoelectrodes with different photocurrents and constant photopotential were obtained by simply controlling the electrode area. The comparison of their PICP performance reveals the efficient way to improve the PICP performance from the perspective of both photocurrent and photopotential. Therefore, this work not only reveals the synergistic mechanism of semiconductors and metals on the PICP performance, but also plays an important role in guiding how to efficiently improve the PICP performance. [ABSTRACT FROM AUTHOR]

Abstract SrTiO 3 is a promising material for the photoelectrochemical (PEC) cathodic protection technology due to its intrinsic band structure. Its disadvantage of light absorption only in the ultraviolet region can be effectively solved by Cr doping. The Cr dopant usually exists as two states of Cr3+ and Cr6+, among which the latter one usually behaves as the trapping center for the photoinduced electrons and leads to the decrease of the PEC performance. In this paper, a hydrogen treatment process is performed on the Cr-doped SrTiO 3 to reduce the Cr6+. It is verified that hydrogen treatment reduces Cr6+ to Cr3+, leading to the increase of the concentration of the charge carriers and the decrease of the charge transfer resistance. And also, hydrogen treatment induces the formation of oxygen vacancy, which leads to the negative shift of conduction band potential and the increase of the concentration of the charge carriers. The effect of the hydrogen treatment temperature is further studied in this work. Higher temperature will promote the reduction degree of Cr6+ and increase the concentration of oxygen vacancy. However, hydrogen treatment with excessively high temperature will induce too high concentration of oxygen vacancy, which would act as the recombination centers of the photogenerated charge carriers, suppress the mobility conduction and thus lead to the decrease of the PEC performance. Therefore, benefiting from the Cr6+ reduction and modification with appropriate concentration of oxygen vacancy, the Cr-doped SrTiO 3 with hydrogen treatment at 250 °C shows the optimal PEC cathodic protection performance in NaCl solution. Highlights • H 2 treatment was performed on the Cr-doped SrTiO 3. • H 2 treatment reduces the Cr6+ and induces the formation of oxygen vacancy. • Photoelectrochemical cathodic protection performance is significantly increased after H 2 treatment. • Appropriate H 2 treatment temperature is necessary for the enhanced performance. [ABSTRACT FROM AUTHOR]

Abstract Graphitic carbon nitride (g-C 3 N 4) usually shows amphoteric property in a neutral solution. In this work, a K&I co-doped g-C 3 N 4 is prepared by simply sintering the mixture of dicyandiamine, KI and I 2. The K&I co-doping modulates the band structure of g-C 3 N 4 with pulling the Fermi level toward its conduction band minimum. The obtained K&I co-doped g-C 3 N 4 (K&I-C 3 N 4) generates positive photocurrents over the whole investigated potential range, exhibiting a typical n-type semiconductor characteristic. Therefore, the K&I co-doping transforms the g-C 3 N 4 from amphoteric to n-type semiconductor. Also, the prepared K&I-C 3 N 4 shows widened light absorption range and enhanced separation efficiency of the photogenerated charge carriers, which results in the dramatically enhanced photoelectrochemical performance. Highlights • A K&I co-doped g-C 3 N 4 (K&I-C 3 N 4) with an evident n-type characteristic was prepared. • The K&I co-doping pulled the Fermi level of g-C 3 N 4 toward its conduction band. • K&I-C 3 N 4 generated positive photocurrents over whole investigated potential range. • The K&I co-doping increased the electrical conductivity of g-C 3 N 4. • K&I-C 3 N 4 showed dramatically enhanced photoelectrochemical performance. [ABSTRACT FROM AUTHOR]

In this study, S-doped graphitic carbon nitride (S-C3N4) was prepared using the high-temperature polymerization method, and then S-C3N4/AgCdS heterojunction photocatalyst was obtained using the chemical deposition method through loading Ag-doped CdS nanoparticles (AgCdS NPs) on the surface of S-C3N4. Experimental results show that the AgCdS NPs were evenly dispersed on the surface of S-C3N4, indicating that a good heterojunction structure was formed. Compared to S-C3N4, CdS, AgCdS and S-C3N4/CdS, the photocatalytic performance of S-C3N4/AgCdS has been significantly improved, and exhibits excellent photocatalytic degradation performance of Rhodamine B and methyl orange. The doping of Ag in collaboration with the construction of a Z-scheme heterojunction system promoted the effective separation and transport of the photogenerated carriers in S-C3N4/AgCdS, significantly accelerated its photocatalytic reaction process, and thus improved its photocatalytic performance. [ABSTRACT FROM AUTHOR]

This article specifically addresses the issue that there is no suitable method to determine the semiconductor types of non-uniformly distributed corrosion products. The photoinduced volt-ampere (i-V) curve is proved to be able to accurately measure the p/n type of corrosion products, in addition, it can also be used to study the transfer direction of the photogenerated electrons and quantitatively measure the photoelectrochemical effects of the corrosion products with semiconducting properties. This work will help to promote the study of the influencing mechanism of light illumination on corrosion process of metals and the photoelectrochemical cathodic protection mechanism. • A photoinduced i-V curve method was developed to judge the p/n type of corrosion products. • It shows obviously superiority over the common used Mott-Schottky plots. • It can be used to study the transfer direction of the photogenerated electrons. • It can be used to quantitatively study the photoelectrochemical effects. [ABSTRACT FROM AUTHOR]

Photoelectrochemical cathodic protection is emerging as a green and environmental method to protect metals against corrosion. Graphitic carbon nitride (g-C 3 N 4) shows great application potential in this area because of its high efficiency, high stability and low cost. However, the pristine g-C 3 N 4 shows amphoteric properties, resulting in its failure in providing photoelectrochemical cathodic protection for the coupled metal in NaCl solution. In this work, a K&I co-doping technique was performed to modulate the band structure of g-C 3 N 4 , and an n-type g-C 3 N 4 (n-C 3 N 4) was obtained. The changes in the molecular structure were studied by SEM, HRTEM, XRD, EDS, XPS and FT-IR technologies. The n-type semiconductor characteristics were verified by the photoinduced i-V curves, SKP potential distributions and pH drift techniques. The n-C 3 N 4 can generate positive photocurrent in the whole investigated potential range, making it able to provide photoelectrochemical cathodic protection for the coupled 316L stainless steel in NaCl solution. This work is very helpful for promoting the application of g-C 3 N 4 in the fields of the photoelectric conversion and the photoelectrochemical cathodic protection. • An n-type g-C 3 N 4 was prepared to modulate its amphoteric property. • n-C 3 N 4 shows increased Fermi level and generates positive photocurrents. • n-C 3 N 4 can provide PECCP for 316L SS in NaCl solution. • Photocurrent is the criterion for predicting the PECCP performance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The global annual consumption of marine metal corrosion is a significant challenge to the service life of metals and the development of marine strategies. A tri-dimensional AgInS2/In2S3 co-modified TiO2 nanobush (NB) superstructure photoanode is constructed. It shows superior photoelectric cathodic protection (PECP) characteristic for pure copper whose self-corrosion potential is more negative in simulated natural marine environment without additional any hole scavengers under simulated solar light illumination. Origin from the more negative energy level potential of AgInS2/In2S3, the quasi-Fermi level of the photogenerated electrons of TiO2 NB/AgInS2/In2S3 was pull to a more negative position, reinforcing the transmission of photogenerated electrons to the pure copper whose self-corrosion potential is more negative. The sensitizer AgInS2 together with the assistant layer In2S3 dramatically enhances the PECP performance of TiO2 NB/AgInS2/In2S3. The tri-dimensional ultrafine branch-like architecture of TiO2 NB with the nanoparticles quickens the collection and transfer of photogenerated electrons to the metallic pure copper. This environmentally friendly 3D photoanode structure provides a good reference for the optimized construction of photoelectric materials for marine metal corrosion protection. The tri-dimensional AgInS2/In2S3 co-modified TiO2 nanobush superstructure photoanode possesses superior photoelectric cathodic protection characteristic for pure cooper whose self-corrosion potential is more negative in simulated marine environment under simulated solar light illumination. [ABSTRACT FROM AUTHOR]

Photo‐electrochemical cathodic protection (CP) technology is considered to be a green metallic corrosion protection technology that uses solar energy to protect from corrosion and does not consume any anode materials. In this work, a CdIn2S4/WO3 nanocomposite photoelectrode was prepared, and its photo‐electrochemical CP performance and mechanism were studied and analyzed. WO3 has a well band matching with CdIn2S4, leading to a significantly enhanced photo‐electrochemical CP performance of the nanocomposite. Meanwhile, as confirmed in this work, the CdIn2S4/WO3 nanocomposite can store photoinduced electrons under light illumination through intercalation reactions and changing the valence state of tungsten. Moreover, it can discharge in the dark state to provide continuous CP for the coupled metals. This research will promote the practical application process of the photo‐electrochemical CP technology. [ABSTRACT FROM AUTHOR]

A novel nanoflower-structured CdS/Co 9 S 8 Z-scheme heterojunction photocatalyst was established to explore the photocatalytic hydrogen production performance. The synergistic effect of the hierarchical structure and the Z-scheme heterojunction makes the photogenerated charge carriers quickly and efficiently transfer to the surface of the photocatalyst, which accelerates the photocatalytic hydrogen production process. • A novel Co 9 S 8 hierarchical structure was prepared by a simple solvothermal method without template. • CdS NPs were deposited on the surface of hierarchical Co 9 S 8 to establish CdS/Co 9 S 8 Z-scheme heterojunction system. • CdS/Co 9 S 8 heterojunction photocatalyst displays an excellent photocatalytic hydrogen production performance. • The synergism of hierarchical structure and Z-scheme heterojunction accelerates the photocatalytic hydrogen production process. Hierarchical structure can significantly increase the reactive sites and provide advantages for heterojunction engineering in the field of photocatalysis. However, it is still a great challenge to realize efficient photocatalytic hydrogen production by controlling the band structure and constructing Z-scheme heterojunction system based on the hierarchical photocatalyst. In this paper, a CdS/Co 9 S 8 Z-scheme heterojunction system was prepared by depositing CdS nanoparticles on nanoflower-structured Co 9 S 8 hierarchical photocatalyst, which showed enhanced photocatalytic hydrogen production performance. The photocatalytic hydrogen production rate of the CdS/Co 9 S 8 Z-scheme heterojunction system is 11.60 mmol g−1 h−1, which is 13.6 and 55.2 times that of CdS and Co 9 S 8 , respectively. The synergistic effect of the hierarchical structure and the Z-scheme heterojunction makes the photogenerated charge carriers quickly and efficiently transfer to the surface of the photocatalyst, which accelerates the photocatalytic hydrogen production process. [ABSTRACT FROM AUTHOR]

In this paper, Mg-doped CdS nanorods (MgCdS) were prepared by a simple solvothermal method to investigate the band structure and enhanced photocatalytic degradation performance under visible light illumination. Mg element is successfully doped into the lattice of CdS and it doesn't destroy the nanorod structure of CdS. The band gap of CdS is widened by Mg doping. The prepared MgCdS shows improved photocatalytic degradation performance than CdS, and 5% MgCdS has the optimal photocatalytic degradation performance, which can degrade approximately 96% RhB in 70-min visible light illumination. The enhanced photocatalytic degradation performance of 5% MgCdS is due to the increased photogenerated charge carrier concentration and the effectively suppressed recombination of photogenerated carriers. • Mg-doped CdS nanorods were prepared by a simple solvothermal method. • The band structure of CdS and Mg-doped CdS were analyzed. • 5%MgCdS displays a significantly enhanced photocatalytic degradation performance. • The mechanism of the enhanced photocatalytic performance of MgCdS was analyzed. [ABSTRACT FROM AUTHOR]

The preparation technologies of thin films are of great significance in the fields of photocatalysis and photoelectrochemistry. Reasonable design and construction of a thin-film photoelectrode is still a great challenge to improve its photoelectrochemical (PEC) performance and stability. In the present work, a novel three-dimensional (3D) sponge-like microporous CdS film was prepared using solvothermal method, and its PEC performance and stability were studied. With the increase of the hydrothermal treatment times, CdS crystalline grains continue to grow on the etched Ti substrate. The prepared CdS thin-film photoelectrode with 3D sponge-like microporous structure possesses excellent PEC performance, and its stability is also greatly improved. The 3D sponge-like microporous structure can significantly increase the light absorption and utilization and improve the conversion efficiency of the CdS thin-film photoelectrode, thereby enhancing its PEC performance. This work provides a new idea for the design and preparation of thin-film photoelectrodes with high PEC performance and stability Unlabelled Image • A novel 3D sponge-like microporous CdS thin-film photoelectrode was prepared using solvothermal method. • The microporous structure of the CdS film significantly increases the light absorption and utilization of CdS. • The CdS thin-film photoelectrode has excellent photoelectrochemical performance and stability. • The CdS thin-film photoelectrode has high photoelectric conversion efficiency. [ABSTRACT FROM AUTHOR]

• BiOCl photocatalysts with different morphologies were prepared. • The photocatalytic performance of BiOCl-6 was significantly enhanced. • The energy band structure of BiOCl photocatalysts were regulated. • The mechanism for the enhanced photocatalytic performance was proposed. BiOCl photocatalysts with different morphologies were prepared by controlling the adding amount of HCl using a simple one-step solvothermal method, the hierarchical structure of BiOCl changes from nanoneedles to nanosheets and the space between the hierarchical structure increases with the increase of the adding amount of HCl. BiOCl-6 possesses the best photocatalytic rhodamine B (RhB) degradation performance under white light illumination. BiOCl-6 has the more negative conduction band potential, thus the electrons on the conduction band have stronger reduction ability. Free radical trapping experiments show that superoxide radicals play the major role in the photocatalytic RhB degradation of BiOCl-6. [ABSTRACT FROM AUTHOR]

• TiO 2 /MgTi x O y multiphase-heterojunction film was successfully prepared. • SKP is used to measure the surface work function of the photoelectrodes. • TiO 2 /MgTi x O y exhibits significantly enhanced PECCP Performance. • TiO 2 /MgTi x O y shows high PECCP stability. • The mechanism of TiO 2 /MgTi x O y multiphase heterojunctions for PECCP is proposed. Heterojunction engineering, as a rising star in the photoelectrochemical cathodic protection (PECCP) field, contributes to promote the separation of the photoinduced electrons and holes. In this paper, the TiO 2 /MgTi x O y multiphase-heterojunction film was prepared and its PECCP performance was studied. Due to a good energy band alignment gradient formed between the multiphases, the separation efficiency of the photoinduced electrons and holes generated by TiO 2 /MgTi x O y are dramatically enhanced, leading to its good PECCP performance and high stability. SKP is, for the first time, used to study the surface work function of the TiO 2 /MgTi x O y multiphase-heterojunction film for characterizing its PECCP performance. [ABSTRACT FROM AUTHOR]

MoS 2 /g-C 3 N 4 heterojunction photocatalysts were successfully prepared using vacuum freeze drying method. The heterojunction structure promotes the separation efficiency of the photogenerated charge carriers of MoS 2 /g-C 3 N 4 , resulting in its significant increase of the photocatalytic performance. • The MoS 2 /g-C 3 N 4 heterojunction photocatalysts were prepared by vacuum freeze drying method. • The photocatalytic performance of the prepared MoS 2 /g-C 3 N 4 heterojunction photocatalysts were significantly enhanced. • The mechanism for the enhanced photocatalytic performance of the prepared MoS 2 /g-C 3 N 4 heterojunction photocatalysts was proposed. The MoS 2 /g-C 3 N 4 heterojunction photocatalyts were successfully synthesized by vacuum freeze drying method and mechanical mixing method in this paper. The pore size and specific surface area of the MoS 2 /g-C 3 N 4 -3% (MC-3%) heterojunction photocatalyst prepared by the vacuum freeze drying method are much higher than those prepared by mechanical mixing method. The photocatalytic hydrogen production rate of MC-3% reaches 30.9 μmol h−1, which is approximately 2.6 times that of pure g-C 3 N 4 , 7.3 times that of pure MoS 2 and 2.4 times that of MC-3% synthesized by mechanical mixing method. And also, the photocatalytic rhodamine B degradation performance of MC-3% is better than that of pure g-C 3 N 4 and pure MoS 2. The significant promotion of the photocatalytic performance of MC-3% synthesized by vacuum freeze drying method are due to the larger specific surface areas and the formation of heterojunctions between MoS 2 and g-C 3 N 4 , which provides more active sites for the photocatalytic reactions and increases the separation efficiency of the photogenerated electrons and holes, thus enhances the photocatalytic performance of g-C 3 N 4. The vacuum freeze drying method is very simple, and the prepared photocatalyst by this method has good performance, which can be widely used in the preparation of composite materials and porous materials. [ABSTRACT FROM AUTHOR]

Effective state estimation is critical to the security operation of power systems. With the rapid expansion of interconnected power grids, there are limitations of conventional centralized state estimation methods in terms of heavy and unbalanced communication and computation burdens for the control center. To address these limitations, this paper presents a multi-area state estimation model and afterwards proposes a consensus theory based distributed state estimation solution method. Firstly, considering the nonlinearity of state estimation, the original power system is divided into several non-overlapped subsystems. Correspondingly, the Lagrange multiplier method is adopted to decouple the state estimation equations into a multi-area state estimation model. Secondly, a fully distributed state estimation method based on the consensus algorithm is designed to solve the proposed model. The solution method does not need a centralized coordination system operator, but only requires a simple communication network for exchanging the limited data of boundary state variables and consensus variables among adjacent regions, thus it is quite flexible in terms of communication and computation for state estimation. In the end, the proposed method is tested by the IEEE 14-bus system and the IEEE 118-bus system, and the simulation results verify that the proposed multi-area state estimation model and the distributed solution method are effective for the state estimation of multi-area interconnected power systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • WO 3 /ZnIn 2 S 4 composite with special flower-like structure was successfully prepared. • WO 3 /ZnIn 2 S 4 exhibits significantly enhanced photoinduced cathodic protection performance. • WO 3 /ZnIn 2 S 4 shows excellent electron storage capability. • Mechanism of WO 3 /ZnIn 2 S 4 composite for photoinduced cathodic protection and electron storage was proposed. In this paper, the WO 3 /ZnIn 2 S 4 composite with special morphology of flower-like structures was prepared by hydrothermal method and its performance of photoinduced cathodic protection (CP) and continuous CP in the dark was studied. The construction of the WO 3 /ZnIn 2 S 4 composite with special morphology is based on the following considerations. Firstly, the stacking connections of the nanoflakes of flower-like structured WO 3 and ZnIn 2 S 4 forms two-dimensional electron transport channels, which is beneficial to the directional transport of photogenerated electrons; Secondly, the heterojunction electric field formed at the WO 3 /ZnIn 2 S 4 interface can accelerate the separation of photogenerated carriers; Finally, taking advantage of electron storage properties of WO 3 and good photoinduced CP performance of ZnIn 2 S 4 with a relatively negative conduction band potential, the WO 3 /ZnIn 2 S 4 composite with excellent performance of photoinduced CP and continuous CP in the dark is obtained. The WO 3 /ZnIn 2 S 4 system can negatively shift the potential of 304 SS by 332.8 mV, and can store 0.17 C of electricity when light illumination duration is 2 h, which is enough to provide 11.88 h continuous CP for 304 SS in dark state. This study realizes long-term CP in the dark, and provides the possibility for practical application of the photoinduced CP technology. [ABSTRACT FROM AUTHOR]

• ZnIn 2 S 4 /TiO 2 nanoflowerbush photoanode was prepared by facile hydrothermal method. • The nanoflower-like ZnIn 2 S 4 was tightly incorporated on ultrafine branched TiO 2 NB. • The heterojunction greatly promotes the transfer of the photogenerated carriers. • ZnIn 2 S 4 /TiO 2 NFB exhibits photoinduced CP performance for metals in NaCl solution. [Display omitted] Boosting the photoinduced cathodic protection (CP) for metals in NaCl solution is crucial for achieving the application of photoelectrochemical conversion in marine corrosion protection. An environmentally friendly three-dimensional ZnIn 2 S 4 /TiO 2 nanoflowerbush (NFB) photoelectrode was constructed with sufficient interfacial incorporation based on the ultrafine branched TiO 2 nanobush substrate via a facile in situ hydrothermal method. This ZnIn 2 S 4 /TiO 2 NFB nanoheterojunction composite behaves excellent photoinduced CP performance for metallic materials. This is owing to the optimized construction of photoelectrode with relatively negative band potential, wide solar spectrum response, effective generation and collection of photoinduced electrons. The morphology, distribution and performance of ZnIn 2 S 4 vary with different substrates. The pure ZnIn 2 S 4 powder is nanoflower sphere composed of a lot of thin petals; when ZnIn 2 S 4 grow onto the FTO glass, the ZnIn 2 S 4 petals are distributed vertically on the two-dimensional structure; when ZnIn 2 S 4 grow on the three-dimensional ultrafine branched TiO 2 nanobush substrate, a ZnIn 2 S 4 /TiO 2 NFB architecture with ultrafine TiO 2 branchlet cores are formed. This ZnIn 2 S 4 /TiO 2 NFB photoelectrode can achieve efficient photoinduced CP performance for pure copper and low alloy steels with different negative self-corrosion potentials, such as Cu (−0.18 V), E40 (−0.45 V), Q345 (−0.55 V) and Q235 carbon steel (−0.65 V) under simulated sunlight irradiation in NaCl solution without additional hole scavengers, and the photoinduced CP current densities reach as high as 170, 72, 63 and 44 μA cm−2, respectively. The high-efficiency photoinduced CP performance is closely related to the band structure gradient matching between the TiO 2 and ZnIn 2 S 4 , prompting both the widened absorption of solar spectrum and high-efficiency transfer of the photogenerated electron–hole pairs. Importantly, the negative band potential of ZnIn 2 S 4 endues a lower surface work function which benefits the electron transport to the under-protected metallic materials to achieve photoinduced CP. This photoelectrode exhibits huge photoinduced CP application potential in marine environments. [ABSTRACT FROM AUTHOR]

Cathodic protection, electron storage, materials science, nanotechnology, photo-electrochemistry Keywords: cathodic protection; electron storage; materials science; nanotechnology; photo-electrochemistry EN cathodic protection electron storage materials science nanotechnology photo-electrochemistry 11479 11479 1 08/16/21 20210811 NES 210811 B Photoelectrochemical cathodic protection b technology is considered to be a green technology that protects metals from corrosion as it uses solar energy for corrosion protection and does not consume any anode materials. Cover Feature: The CdIn2S4/WO3 Nanosheet Composite Has a Significantly Enhanced Photo-electrochemical Cathodic Protection Performance and Excellent Electron Storage Capability (Chem. Eur. J. 45/2021). [Extracted from the article]

• Two-phase WO 3 photoelectrodes with different morphologies were obtained. • WO 3 -3 photoelectrode has the best photoinduced cathodic protection performance. • The mechanism for the enhanced performance of WO 3 -3 was proposed. In this paper, two-phase WO 3 photoelectrodes with different morphologies were obtained by controlling the concentration of Na 2 WO 4 in the precursor solution, and their photoinduced cathodic protection(CP) performance was explored. The heterojunctions formed between hexagonal and monoclinic WO 3 are favorable for the directional separation of photogenerated carriers. Meanwhile, the ordered growth of WO 3 nanorods perpendicular to Ti substrate is conducive to the directional transmission of photogenerated carriers, which makes it have good photoinduced CP performance. [ABSTRACT FROM AUTHOR]

• Vertically-aligned 2D TiO 2 nanosheets array (NSA) substrate was prepared. • The TiO 2 NSA/AgInSe 2 /In 2 Se 3 multijunction system was prepared. • TiO 2 NSA/AgInSe 2 /In 2 Se 3 promotes the separation of photoinduced carriers. • TiO 2 NSA/AgInSe 2 /In 2 Se 3 exhibits the enhanced PEC performance. • TiO 2 NSA/AgInSe 2 /In 2 Se 3 exhibits efficient PECCP performance for 316 L SS. 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" AgInSe 2 /In 2 Se 3 sensitized TiO 2 nanosheet array (NSA) photoanode was prepared. Vertically-grown two-dimensional TiO 2 NSA with the multijunction of TiO 2 NSA/AgInSe 2 (7)/In 2 Se 3 (3) improves the separation efficiency and the transfer of photoinduced charge carriers compared with single AgInSe 2 sensitized TiO 2 NSA. The TiO 2 NSA/AgInSe 2 /In 2 Se 3 photoanode achieves highly efficient photoelectrochemical cathodic protection performance for 316LSS in NaCl solution under AM1.5 light illumination. [ABSTRACT FROM AUTHOR]

The microstructure of semiconductor materials is of vital importance to its photoelectrochemical performance because the well-optimized special architecture offers rapid electron transport pathways for the photogenerated electrons and provides large areas for light harvesting. In the present paper, an ultrafine hyperbranched TiO 2 nanolawn (TiO 2 UFHBNL) photoanode was prepared through a facile one-step solvothermal method under employing a suitable dosage of H 2 O and diethylene glycol (DEG). Along with varying the dosages of H 2 O and DEG in the solvothermal process, both the crystal structure and morphology of the prepared TiO 2 nanosubstrate changed gradually. With the increase of the dosage of H 2 O and DEG from 5 mL: 35 mL–10 mL: 30 mL and further to 20 mL: 20 mL, the crystal phase of the TiO 2 nanosubstrate transforms from amorphous state to anatase phase and eventually to anatase-rutile mixed phases. And, the morphology of TiO 2 nanosubstrate changes from thick nanotrees to UFHBNL architecture and then to nanoparticles. The TiO 2 UFHBNL photoanode with the ultrafine hyperbranched architecture (diameter of 5–10 nm) after the CdS nanoparticles (5 nm) decoration shows an extremely enhanced photoelectrochemical performance. The ultrafine hyperbranched TiO 2 substrate also induces the super-refinement of the deposited CdS nanoparticles (5 nm) on the sub-branches. A maximum photocurrent density of 5.6 and 3.8 mA cm−2 are obtained under AM1.5 light and visible light illumination, respectively. The highly efficient photoelectrochemical performance is attributed to the decreased charge transfer barrier which contributes to fast charge transport and decreased recombination efficiency of the carriers. This strategy is beneficial for designing the high-performance photoanodes with the ultrafine hyperbranched architecture. A high-efficient TiO 2 photoanode with ultrafine hyperbranched nanolawn (UFHBNL) architecture sensitized with ultrafine CdS nanoparticles was prepared and optimized through a facile one-step hydrothermal method following by sequential ion layer absorption and reaction technique. The ultrafine TiO 2 nanobranches can greatly reduce the charge transfer barrier and promote the rapid transfer of the photoinduced electrons, finally offer the fast electron transport pathways. Image 1 • TiO 2 ultrafine hyperbranched nanolawn (UFHBNL) photoanode with ultrafine CdS nanoparticles was prepared. • The morphology and structure of TiO 2 substrate is adjusted by controlling dosages of H 2 O and DEG. • The CdS/TiO 2 UFHBNL photoanode shows a maximum photocurrent density of 5.6 mA cm−2. • The TiO 2 UFHBNL architecture endows fast charge transport and large light harvest area. [ABSTRACT FROM AUTHOR]