TiO 2 nanotube electrodes are commonly used in photoelectrocatalytic applications; however, their poor conductivity limits their electrochemical potential. In this work, we have prepared self-doped TiO 2 nanotube electrodes by electrochemical anodization followed by electrochemical cathodic polarization. Electrochemically self-doped TiO 2 nanotube (SD-TNT) electrodes were prepared by cathodic polarization and subsequently decorated with Pt nanoparticles (3.3 ± 0.6 nm) via impregnation and electrochemical reduction. SD-TNT supports a complete Pt voltammetric profile and enables ethanol electro-oxidation in the dark. In contrast, Pt-decorated pristine nanotubes (Pt/TNT) exhibit only hydrogen adsorption/desorption features and no anodic currents in acidic media. Under simulated solar irradiation, pristine TNT exhibits the highest photocurrents and product formation. At the same time, both self-doping and Pt decoration decrease the photocurrent density, highlighting a trade-off between enhanced dark conductivity and increased recombination in highly defective TiO 2 . Nevertheless, Pt/SD-TNT electrodes combine dark electrocatalytic activity with photoresponse, operating in a dual mode that is relevant for devices under intermittent illumination. These results clarify the distinct roles of self-doping and Pt decoration on TiO 2 nanotube electrodes, highlighting a trade-off between maximizing photocurrent and enabling Pt-based electrocatalysis on a normally rectifying semiconductor support. • ~3 nm Pt nanoparticles deposited on TiO 2 nanotubes (TNT) by adsorption/reduction. • On undoped TiO 2 , Pt voltammetry is limited to the cathodic region in acid. • Self-doping activates TiO 2 nanotubes for dark Pt-catalyzed ethanol oxidation. • Pt and self-doping (SD) lower TiO 2 photocurrent, revealing a conductivity trade-off. • Pt/SD-TNT electrodes work in dual mode: dark and photoassisted ethanol oxidation.

Developing efficient and durable nonprecious cathodes for the hydrogen evolution reaction (HER) is crucial for industrial alkaline water electrolysis (AWE). NiMo-based materials are among the highly active nonprecious HER electrocatalysts at present and are expected to replace noble-metal catalysts. However, their practical application is hindered by the performance degradation under the industrial operating conditions, especially fluctuating conditions imposed by an intermittent renewable power supply. This study systematically carried out a series of experiments and elucidated the degradation mechanisms of the NiMo-based cathode (Ni4Mo-MoO2) during intermittent AWE. First, the dissolved oxygen that inevitably diffuses from the anode to the cathode chemically corrodes the NiMo catalyst in concentrated alkaline electrolyte at high temperature, thus reducing active sites and leaching critical components, notably Mo. Simultaneously, the reverse current generated during start-stop operations induces anodic polarization of the NiMo cathode, accelerating its degradation through electrochemical oxidation. Moreover, driven by external gas-liquid flow scouring and internal stress from redox-induced phase transformation, the catalyst layer separates from the substrate, leading to serious mechanical detachment. These factors collectively cause severe degradation in the activity of the NiMo cathode. This work provides important guidelines for developing next-generation nonprecious metal cathodes with lasting stability.

Driven by the rapid development of 5G/6G communications, high-performance computing, and artificial intelligence, the metallization of high-aspect-ratio through-holes (THs) in printed circuit boards (PCBs) imposes stringent requirements on the thickness uniformity and interconnect reliability of electroplated copper layers. This study systematically investigates the application of a novel leveler, thiazolyl blue (MTT), for PCB THs' electroplating, successfully realizing high-quality conformal deposition in high-aspect-ratio (10:1) THs. Electrochemical analyses demonstrate that MTT significantly enhances the cathodic polarization and effectively inhibits the reduction of Cu2+. Meanwhile, microscopic morphological characterizations confirm that MTT exhibits excellent leveling capability, reducing the surface roughness of the copper deposit to as low as 0.147 μm. Furthermore, density functional theory (DFT) calculations reveal that the high inhibitory efficiency of MTT originates from the dominant interfacial adsorption of MTT at the cathode, with the bulk cation-π interaction with Cu2+ contributing as a minor secondary effect at the microscopic level. Crystallographic and interfacial wettability analyses further indicate that MTT effectively refines the grain size and promotes the preferential growth of the Cu(200) plane while improving the wettability of the plating bath. In practical high-aspect-ratio through-hole plating tests, the introduction of MTT substantially increases the throwing power (TP) from 25.2% to 96.8%. Based on these results, a competitive interfacial polarization remodeling mechanism governed by multiphysics coupling is proposed to elucidate the intrinsic role of MTT in promoting conformal through-hole deposition. This work provides a solid theoretical foundation and practical engineering guidance for the fabrication of highly reliable, high-frequency 3D interconnected PCB structures.

Micro-nano biochar interfaces promote adsorption-reduction coupling to accelerate bioelectrodechlorination in groundwater.

Interfacial tandem catalysis in Co/WC heterojunctions for efficient nitrate-to-ammonia electrosynthesis.

Electrochemical and stress corrosion behaviors of low-alloy high-strength steel in the soil environment of Western China

ABSTRACT Plasma electrolytic oxidation (PEO) coatings commonly suffer from discharge‐induced porosity and cracking, which limit their protective performance. Inward coating growth has been reported as an effective route to improve coating density; however, the governing mechanism of this phenomenon remains unclear. In this study, the effect of bipolar current, with a constant negative current component and dynamically varied positive current density, on PEO coating growth behavior is systematically investigated on AZ91D magnesium alloy. Microstructural observations reveal the formation of dense inward‐grown regions that are free of discharge‐channel‐related porosity. Elemental mapping demonstrates selective inward incorporation of O and F, whereas larger anions such as phosphate remain confined to the outer layer. Voltage–time responses, combined with SEM, EDS, XRD, Raman, and FTIR analyses, indicate that inward growth cannot be explained solely by thermal diffusion or discharge‐channel transport. Instead, the results show that the negative current component actively promotes lattice‐mediated inward anion diffusion through electrostatic assistance in addition to thermal activation. We propose a revised coating growth mechanism, in which repeated cathodic polarization suppresses outward discharge activity and enables electrically assisted inward diffusion through the oxide lattice. These findings provide new insight into inward coating growth during bipolar PEO and demonstrate that negative current is a key parameter for tailoring dense, low‐porosity oxide coatings.

Abstract La-Sr-Mn-O (LSM) and La-Sr-Ga-Mg-O (LSGM) perovskite-like oxide ceramics have been extensively studied owing to their exceptional electrochemical properties and thermal stability, attracting special interest for the development of next-generation Intermediate Temperature (IT)-Solid Oxide Fuel Cells (SOFCs) technologies. In this work, we present the synthesis of La0.8Sr0.2MnO3 cathode and La0.8Sr0.15Ga0.85Mg0.15O3 electrolyte powders prepared by fast solution combustion, and a comprehensive study on their electrochemical performance at typical IT-SOFCs operation temperatures. X-Ray Diffraction (XRD) and Rietveld refinement confirmed the rhombohedral LSM and orthorhombic LSGM perovskitelike crystalline structures, with minor secondary phases that may influence performance. Electrochemical impedance spectroscopy of symmetric LSM/LSGM/LSM cells in air (600-800°C) revealed a substantial decrease in cathodic polarization resistance (Rp) with increasing temperature, although the absolute values remained high. Arrhenius analysis yielded an activation energy of approximately 1.15 eV for the oxygen reduction reaction, indicating sluggish interfacial kinetics relative to those of typical LSM-based cathodes at approximately 800°C. The elevated Rp and activation barrier were attributed to insufficient adhesion and limited chemical compatibility at the screen-printed LSM-LSGM interface. Therefore, optimizing ink rheology and thermal processing was proposed to improve interfacial bonding, as well as adopting composite LSGM-LSM cathode architectures that expand the triple-phase boundary density and mitigate polarization losses. Overall, the proposed rapid solution route enabled the preparation of structurally appropriate LSM and LSGM with properties suitable for IT-SOFC operation. Our results provide insights into the interplay between synthesis, microstructure, transport, and interfacial phenomena, guiding the development of lower-temperature SOFCs.

Hydrodynamic intensification of red soil microbial fuel cells: enhanced Acid Red 73 degradation and bioelectricity generation under free-fall influent.

Cathodic protection is an effective strategy for mitigating corrosion in marine engineering applications. This study systematically investigates the evolution of surface states and corrosion resistance of 70/30 cupronickel tubes with pre-formed stable protective films under cathodic polarisation in natural seawater. Electrochemical impedance spectroscopy (EIS) and linear polarisation resistance (LPR) were employed to evaluate the electrochemical behaviour. Key findings reveal that a negative shift in polarisation potential (from −350 to −750 mV) reduces the barrier properties of the pre-existing protective film by nearly one order of magnitude, yet simultaneously accelerates the formation of a dense calcareous deposit layer. Notably, the innovation lies in the quantitative correlation between EIS-derived parameters and deposit growth: charge transfer resistance ( R ct ) increases significantly from 14,260 to 44,790 Ω·cm 2 , while the power index value of constant phase element (CPE) suggests the involvement of O 2 diffusion in the electrochemical processes. The novelty is further highlighted by the identification of aragonite as the dominant phase in the calcareous deposits formed at −550 and −750 mV, which contributes to enhanced surface coverage.

A novel cyanide-free gold electroplating bath was developed with 2-hydroxyphosphonoacetic acid (HPAA) as the core complexing agent in this work. Scanning electron microscopy (SEM) observations demonstrate that the obtained gold electrodeposits possess a smooth and compact surface morphology. The crystal structure of the gold electrodeposits was characterized via X-ray diffraction (XRD), and the coating–substrate adhesion was systematically evaluated through scratch tests. Molecular dynamics (MD) simulations were performed to investigate the adsorption interaction between HPAA and metal (Au/Ni) surfaces. The MD simulation results show that all the studied phosphonate-containing derivatives can strongly adsorb on the gold surface and exert a significant inhibitory effect on the electroreduction of gold ions during electrodeposition. Cyclic voltammetry (CV) and other electrochemical tests reveal that the cathodic reduction peak potential of gold shifts significantly negatively after the addition of phosphonate-based organic additives, which effectively enhances the cathodic polarization of gold deposition, delays the gold nucleation rate, and refines the grain size of electrodeposits, ultimately yielding gold electrodeposits with a denser and smoother surface. Owing to its environmental benignity, excellent process stability and superior coating performance, this cyanide-free gold electroplating system exhibits broad application prospects in the field of modern green surface engineering.

A new Ni(III)-based metal-organic coordination polymer (MOCP) of formula [Ni(4,4'-IPDPA)1.5(H2O)3]·6H2O (4,4'-IPDPA = 4,4'-isopropylidenediphenoxyacetate), 1, has been synthesized at ambient temperature using the slow layer diffusion method. The framework of compound 1 was obtained through single-crystal X-ray diffraction (SCXRD). It was comprehensively analyzed by various methods, including powder X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), ultraviolet-visible (UV-vis) spectroscopy, luminescence spectroscopy, Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). Compound 1 shows promising electrocatalytic activity for the oxygen reduction reaction (ORR) in alkaline conditions. With a nearly four-electron reduction mechanism and a half-wave potential of 0.72 V versus a reversible hydrogen electrode (RHE), compound 1 exhibits remarkable ORR performance. The compound 1 most intriguingly showed good long-term stability. In addition to the presence of accessible pores within the framework, the emergence of the reduced Ni(II) moiety from Ni(III) during cathodic polarization is believed to be responsible for the high level of activity. Compound 1 also demonstrated exceptional resistance toward methanol poisoning during the ORR activity. Moreover, the density functional theory (DFT) analysis suggests that the as-prepared Ni3+-ion-based MOCP follows the four-electron-guided ORR pathway with the formation of *O intermediate as the potential-determining step (PDS).

Despite the fact that various studies have proved the efficacy of plant-based extracts as green corrosion inhibitors, the possibility of using unwanted and invasive species as sustainable corrosion inhibitors is still underexplored. In the current study, Putranjiva roxburgii extract (PRWE), which is an abundantly available weed, is, explored as a value-added, eco-friendly corrosion inhibitor to mild steel in a 1.0 M HCl acidic environment. The electrochemical method, the gravimetric analysis, scanning electron microscopy (SEM), and the computational evaluation were used to analyze the PRWE corrosion inhibition performance. These findings indicated the presence of a concentration-related inhibition behaviour, with PRWE being a mixed-type inhibitor, as shown by anodic and cathodic polarization slopes. The corrosion inhibition potential of PRWE was systematically assessed via potentiodynamic polarisation (PDP), Electrochemical impedance spectroscopy (EIS) and weight loss (WL). PRWE exhibited efficiency of 95.57% as determined by EIS and 97.51% as obtained via WL at 298 K that decreased as the temperature was elevated. Increases in charge transfer resistance (Rct) and polarization resistance (Rp) and a reduction in the constant phase element value, confirming the presence of a protective adsorbed layer over the mild steel surface. Theoretical computations also indicated the vigorous adsorption of PRWE components on the steel surface, characterized by a low energy gap (ΔE), which showed good agreement with experimental results. Based on all the above findings, the present work presents weeds as a low-cost, low-utilized, sustainable source of corrosion inhibitors, which have the dual advantage of resisting corrosion and environmental management.

Potential-dependent evolution and degradation of the protective oxide film on 70Cu-30Ni alloy in marine environment

The oxygen reduction reaction (ORR) in living cells efficiently generates energy but is limited for sustainable applications due to inefficient electron transfer across membranes. Here, we report an interspecies cooperative mechanism, termed electro-mutualism, that enables efficient extracellular ORR using an electrotrophic Acinetobacter venetianus RAG-1 (RAG-1) and a non-CO2-fixing electrotrophic Shewanella oneidensis MR-1 (MR-1), sustained by inorganic carbon supplied via a bicarbonate-CO2 equilibrium. Under cathodic polarization, RAG-1 assimilates inorganic carbon and secretes lactate using electrode-derived electrons, which fuels MR-1. In turn, MR-1 releases flavins that interact with the RnfB complex of RAG-1, thereby accelerating the transmembrane electron transfer. This electro-mutualistic cooperation achieves, to our knowledge, the highest reported whole-cell ORR current density (20.9 A/m2) under O2-aerated, neutral-pH conditions, outperforming benchmark Pt/C and laccase cathodes evaluated under identical conditions. The universality of electro-mutualism is further supported by replacing MR-1 with Bacillus subtilis and is predicted to extend across proteobacteria, firmicutes, and actinobacteria. Electro-mutualism thus provides a metal-free, genetically unmodified catalytic strategy for green energy conversion.

2,2'-Bipyridine (Bpy) serves as an essential cathodic polarization additive in the copper electroplating process of photovoltaic silicon wafers. Its presence significantly inhibits biochemical reactions and exhibits toxic effects, thereby emphasizing the urgent need for an effective removal method. This study introduces the development of multi-walled carbon nanotubes (MWCNTs)-supported nickel-manganese bimetallic particles (Ni-Mn@MWCNTs) as 3D electrocatalytic agents for Bpy degradation. Fundamental characterization (FTIR, Raman, XRD, BET, XPS) confirms successful loading of Ni-Mn onto the MWCNTs framework, significantly increasing defect sites and enhancing electrochemical activity. Electrochemical testing indicates optimal performance at a Ni:Mn ratio of 2:1, current density of 4mA/cm2, particle dosage of 4g/L, and electrode spacing of 2cm, achieving 88.09% degradation of Bpy from an initial concentration of 0.98g/L. The system demonstrated efficacy across a broad pH range (1-9), with radical scavenging experiments and Electron Paramagnetic Resonance (EPR) analysis confirming ·OH and ·O2 - radicals as primary active species. Reusability testing confirmed high stability and recyclability. Liquid Chromatography-Mass Spectrometry (LC-MS) and Density Functional Theory (DFT) calculations proposed a plausible Bpy mineralization pathway. Toxicity assessments indicated reduced neurotoxicity to humans and aquatic toxicity for degradation intermediates. Overall, this study provides an innovative, efficient, and environmentally friendly electrochemical solution for removing pyridinium ions from photovoltaic manufacturing wastewater.

Abstract Atmospheric exposure of Ag witness coupons yields corrosion products such as AgCl and Ag 2 S that are highly dependent on local atmospheric chemistry. The principal goal of this study was the synthesis of a comprehensive catalog of silver corrosion product standards with characterization using electrochemical and surface analytical methods. Several silver corrosion products were generated using galvanostatic oxidation with good charge efficiency and were analyzed using coulometric reduction, cathodic polarization, and surface techniques. Average reduction potentials estimated by coulometric reduction were –0.22±0.005 V MSE (Ag 2 O), –0.34±0.01 V MSE (AgCl), –0.50±0.001 V MSE (AgBr), –0.74 V MSE (AgI), and –1.25±0.01 V MSE (Ag 2 S). Results from surface analytical techniques confirmed the presence of supporting halides, sulfides, or oxides. Surfaces were also analyzed after the film was reduced, confirming that coulometric reduction consumed the corrosion product. The standards were used to identify Ag 2 O, AgCl, and Ag 2 S on coupons exposed to two outdoor and 1 indoor environment and the reduction potentials from these coupons were within ±0.01 V MSE of the standards.

The current work examines the impact of isopropanol (IPA) on the electrochemical characteristics of nickel foam and Pd-modified Ni foam electrodes in a 0.1 M NaOH medium, with respect to the kinetics of the hydrogen evolution reaction (HER) over the temperature range of 20–40 °C. Comparative HER/IPA examinations are presented for a highly catalytic polycrystalline Pt electrode. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and cathodic Tafel polarization experiments were carried out in this work, where the IPA concentrations ranged from 1.0 × 10−5 to 1.0 × 10−3 M. The introduction of small amounts of isopropyl alcohol into the working electrolyte noticeably facilitated the catalytic efficiency of the hydrogen evolution reaction on the surface of Ni foam electrodes. This is most likely related to the fact that IPA molecules undergo partial electrooxidation to acetone (qualitatively confirmed by GC-MS analysis) during initial CV cycling, which is believed to significantly diminish the surface tension phenomenon during the HER, thus promoting hydrogen bubble separation from the electrode surface. It should also be noted that acetone will continuously be produced at the Pt anode, making it essential to consider further migration of (CH3)2CO molecules to the working cell compartment. Most importantly, isopropanol was found not to undergo significant surface electrosorption on the nickel foam-based catalysts, which could otherwise significantly inhibit the hydrogen evolution reaction On the contrary, the presence of IPA in the electrolyte solution seems to have a detrimental effect on the kinetics of both the HER and the UPDH (underpotential deposition of H) processes on the surface of the polycrystalline Pt electrode, which is a superior electrochemical catalyst for HER, but highly susceptible to surface contamination.

The influence of rare-scattered indium(Ⅲ) impurity on cathodic polarization and electrowinning process of zinc from acidic sulfate electrolyte

Durable photocathodic protection is an effective approach to mitigate marine metal corrosion, but its performance often suffers from rapid charge recombination and poor band-edge matching of semiconductors. Herein, a hydrogen-bond-mediated molecular bridging strategy is proposed by incorporating polyvinylpyrrolidone (PVP) as a multifunctional interlayer into a WO 3 /TiO 2 heterojunction. 1 H solid-state NMR and theoretical calculations reveal that the carbonyl groups of PVP preferentially form strong hydrogen bonds with surface bridging hydroxyl (Ti–OH) groups, modulating the interfacial structure at the molecular scale. The PVP-engineered WO 3 /TiO 2 interface passivates surface trap states, promotes interparticle charge migration, and induces an interfacial dipole field that shifts the band edges to more negative potentials. These synergistic effects enhance both carrier dynamics and the thermodynamic driving force for electron injection into the protected metal. The optimized WO 3 /PVP/TiO 2 photoelectrode delivers a photocurrent density of 62.5 μA·cm -2 and a cathodic polarization potential of -482 mV ( vs . Ag/AgCl), 2.1-fold and 1.2-fold higher than the PVP-free WO 3 /TiO 2 counterpart, and maintains a polarization potential of approximately -252 mV in darkness after 12 hours of illumination, ensuring long-term protection of 304 stainless steel. This interface design concept offers guidance for engineering efficient, durable photoelectrodes for corrosion protection and related photocatalytic applications. Molecular-scale interface engineering is achieved by introducing a PVP interlayer into WO 3 /TiO 2 . Hydrogen bonding with bridging hydroxyls passivates trap states, enables orbital hybridization, and induces an interfacial dipole, thereby enhancing carrier dynamics and band energetics. This strategy highlights hydrogen-bond modulation as a versatile route to efficient, durable photoelectrodes for photocathodic protection and solar-driven applications. • PVP molecular bridge creates H-bonded interfaces in WO 3 /TiO 2 heterojunction. • NMR and DFT reveal selective H-bonding with Ti–OH bridging hydroxyl surface sites. • H-bonding passivates recombination traps and tunes band edges via dipole fields. • WO 3 /PVP/TiO 2 achieves 62.5 μA cm -2 and sustained "all-weather" metal protection.