Search

SrTiO3 is a promising candidate for photocatalysis because of its tunable band structure and extreme stability. By suitably formulating nanocomposites of SrTiO3 with other materials, it can introduce defects into the crystal lattice and thereby alter its electronic structure favorably for the desired catalytic applications. In this study, a ternary composite in the form of a coating comprising of SrTiO3 nanocubes on yeast-reduced graphene oxide (yrGO) and Ni2P is developed for the generation of hydrogen by visible light-driven water splitting. The in situ tuning on the electronic state of SrTiO3 nanocubes by a self-doping effect from the controlled and simultaneous occurrence of Ti3+ species and oxygen vacancies via the Ti-C bond formation is achieved in the presence of a yeast-assisted reduction of GO in the SrTiO3/yrGO nanocomposite. Consequently, SrTiO3 forms epitaxially self-assembled SrTiO3 nanocubes on the surface of yrGO as a distinctive bush-like structure, which is further integrated with Ni2P matrix resulting in a hierarchical architecture consisting of SrTiO3/yrGO microflowers on the spherical Ni2P beds. This harmonious integration of SrTiO3/yrGO on Ni2P enriches the catalytically active sites facilitated by yrGO together with a straddling band gap alignment in the heterojunction for the efficient separation of the electron-hole pairs. The SrTiO3/yrGO-Ni2P composite coating heterojunction exhibits an outstanding performance toward solar light-driven water splitting and produces 13.25 mmol/g/h of hydrogen with an AQE value of 36.26% under 1 h irradiation after a successful compositional tuning on the coating surface. [ABSTRACT FROM AUTHOR]

The plasma electrolytic oxidation (PEO) coatings have different applications, and their modifications or developments are generally with a specific application target. Therefore, the PEO coating assessments often envisage that particular application without considering other possibilities or infeasibilities of developed PEO coatings from a different perspective. Electrochemical impedance spectroscopy (EIS), a powerful technique for PEO coating assessment, is manifold because it can assess almost every structural, morphological, chemical, and electrochemical feature of PEO coatings. Therefore, a review paper describing an all-purpose EIS behavior of PEO coatings is essential for researchers and engineers for a complete PEO coating assessment beyond their target application. Herein, the relevant PEO coating literature reports sufficient to understand the PEO coating assessment fundamentals are included in this review for researchers and engineers from all perspectives without compiling all literature reports on EIS studies of PEO coatings. [ABSTRACT FROM AUTHOR]

In the quest for sustainable hydrogen production via water electrolysis, the development of high-performance, noble-metal-free catalytic systems is highly desired. Herein, we proposed an innovative strategy for the development of an electrocatalyst by refining the surface characteristics of a NiFeP alloy through microbiological techniques and subsequent enrichment of active sites by tailoring 3D hierarchical flower-like structures with intact and interconnected two-dimensional (2D) Co 3 O 4 . The resultant 3D Co 3 O 4 @NiFeP-5/24h has a porous structure comprised of intercrossed nanoparticles covering the entirety of the catalytic surface. This design ensures comprehensive electrolyte ion penetration and facilitates the release of gas bubbles while reducing bubble adhesion rates. Remarkably, the Co 3 O 4 @NiFeP-5/24h electrode demonstrates superior hydrogen evolution (HER) performance in an alkaline medium, characterized by its high stability, low overpotential (106 mV at a current density of 10 mA cm -2 ), and reduced Tafel slope (98 mV dec -1 ). Besides, the minimized interfacial contact resistance among the phases of electrode and electrolyte emphasizes the high HER performance of the 3D Co 3 O 4 @NiFeP-5/24h electrode. The innovative design and fabrication strategy employed herein holds significant potential for advancing the field of water-splitting electrocatalysis, offering a promising path toward the rational design and development of noble-metal-free electrocatalysts.

Recently, TiO 2 crystals have been modified by transition-metal dopants with different physicochemical structures to attain distinguished properties. Considering the similar ionic sizes of V 4+ (0.058 nm) and Ti 4+ (0.061 nm), vanadium in the +4 state can be effectively incorporated into the crystal lattice of TiO 2 to tune the band gap energy by creating an impurity energy level (V 5+ /V 4+ ) below the conduction band (2.1 eV) and retaining the anatase phase. In vanadium-incorporated TiO 2 (V/TiO 2 ), V 4+ is a good dopant candidate as it can increase the lifetime of the charge carrier and reduce the electron-hole recombination rate, which results in high antibacterial activity under visible light irradiation. The present study explores the V/TiO 2 -based hot-dip zinc coating with enhanced electrochemical properties and long-term stability for combating biocorrosion. All the composites and the coatings are characterized by different techniques, including X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray analysis, confocal laser scanning microscopy, optical surface profilometry, and X-ray photoelectron spectroscopy. The biofilm formation assay and the cell viability assay reveal that the tuned composition of the V/TiO 2 -based hot-dip zinc coating effectively kills the adherent bacteria and inhibits biofilm formation on the surface. The high-charge-transfer resistance (225.67, 223.63, and 242.35 Ω cm 2 ) and the high-inhibition efficiency (92.24, 92.30, and 92.02%) of the tuned composition of the V/TiO 2 -based hot-dip zinc coating confirm its efficient and sustainable antibiocorrosion performance and long-term stability even after an exposure period of 21 days in different bacterial environments. With the inherent antibacterial properties and antibiocorrosion performance of the developed V/TiO 2 -based hot-dip zinc coating, the mild steel substrates can find potential application in different fields, including aquatic and marine environments.

The present paper reports for the first time the development and application of novel Zn wetted CeO 2 (Zn/CeO 2 ) composite galvanic zinc coating to combat microbial induced corrosion (MIC). Zinc metal-metal interaction causes the effective incorporation of composite into the galvanic coating and accordingly increases the active sites for antibiofouling activity. The developed coatings are explored for their anticorrosion/antibiofouling characteristics toward MIC induced by cultured seawater consortia. Enhanced antibiofouling activity of the composite galvanic coating is achieved due to the tuned content of 28 wt % Zn and 34 wt % of Ce. High charge transfer resistance as high as 4.0 × 10 14 Ω cm 2 and low double layer capacitance as low as 3.99 × 10 -8 F are achieved by tuning the structure and composition of the coating. The synergistic effect of Zn and Ce ensures the stability and corrosion resistance of the coatings in a corrosive bacterial environment. Evident decreases in the bacterial attachment and biofilm formation are illustrated using antibiofouling assay. The antibiofouling activity is attributed to the effective reduction of Ce 4+ to Ce 3+ and the shuttling characteristics of oxidation state of CeO 2 . This impairs the cellular respiration and results in bacterial death. Thus, it can be used as an effective coating to protect the steel based equipment in corrosive marine environments to combat marine microorganisms and their interactions. The present study also paves the scope for exploration of similar effective protective systems.