Jialei Zhang

Three-dimensional astrocyte-network Ni–P–O compound with superior electrocatalytic activity and stability for methanol oxidation in alkaline environments

Three Ni–P–O compound catalysts with tunable architectures and compositions have been fabricated using a facile one-pot solvothermal method, which are named astrocyte-network Ni–P (Ni–Pan), silkworm cocoon-like Ni–P (Ni–Psc), and microsphere Ni–P (Ni–Pm), respectively. The final architecture of the Ni–P–O catalysts is strongly dependent on the Ni2+/H2PO2− molar ratio in the reaction system, which leads to a delicate balance between kinetic and thermodynamic growth regimes. Three-dimensional ensemble of Ni–Pan with a higher P content is composed of many amorphous Ni–P nanowires with a diameter of about 4 nm, which delivers a significantly larger BET surface area of 500.5 m2 g−1. Moreover, nickel phosphides and nickel phosphates are formed in the three Ni–P–O samples. Ni–Pan exhibits a higher peak current density of ∼1490 A g−1, better electrode accessibility, faster charge-transfer process, and long-term chronoamperometry stability (≥20 000 s) toward methanol oxidation in alkaline solution, which are superior to most state-of-art Ni–P catalysts and the Ni–Psc and Ni–Pm in this case. The superior catalytic performance of the Ni–Pan catalyst is attributed to its unique microstructure and compositions. According to X-ray photoelectron spectroscopy, a strong electronic interaction between nickel phosphides and nickel phosphates might also contribute to the improved catalytic activity of the Ni–Pan catalyst.

Robust Slippery Coating with Superior Corrosion Resistance and Anti-Icing Performance for AZ31B Mg Alloy Protection

Biomimetic slippery liquid-infused porous surfaces (SLIPSs) are developed as a potential alternative to superhydrophobic surfaces (SHSs) to resolve the issues of poor durability in corrosion protection and susceptibility to frosting. Herein, we fabricated a double-layered SLIPS coating on the AZ31 Mg alloy for corrosion protection and anti-icing application. The porous top layer was infused by lubricant, and the compact underlayer was utilized as a corrosion barrier. The water-repellent SLIPS coating exhibits a small sliding angle and durable corrosion resistance compared with the SHS coating. Moreover, the SLIPS coating delivers durable anti-icing performance for the Mg alloy substrate, which is obviously superior to the SHS coating. Multiple barriers in the SLIPS coating, including the infused water-repellent lubricant, the self-assembled monolayers coated porous top layer, and the compact layered double hydroxide-carbonate composite underlayer, are suggested as being responsible for the enhanced corrosion resistance and anti-icing performance. The robust double-layered SLIPS coating should be of great importance to expanding the potential applications of light metals and their alloys.

Electrodeposition, Morphology, Composition, and Corrosion Performance of Zn-Mn Coatings from a Deep Eutectic Solvent

Different Zn-Mn coatings were successfully electrodeposited on copper substrates from deep eutectic solvent-based electrolytes containing boric acid as an additive. The main objective of this work was to optimize the Zn/Mn ratios and morphologies of the as-electrodeposited Zn-Mn films in order to obtain better corrosion protection performance coatings. The electrodeposition behaviors of Zn-Mn alloys as studied by cyclic voltammetry showed that with increase in electrolyte Mn(II) concentration, Zn(II) ion reduction occurs at higher overpotentials while Mn reduction occurs at lower overpotentials, and this in turn enhances Mn incorporation into the deposit. Characterization results showed that the electrodeposition potential and electrolyte Mn(II) concentration significantly affects the Mn content, crystal structure, surface morphology, and corrosion performance of the deposits. With increase in electrodeposition potential and electrolyte Mn(II) concentration, the alloy Mn increased and the grain morphology was refined. The crystal structure of Zn-Mn deposits consists of Zn and hexagonal close packed ε-phase Zn-Mn at low electrodeposition potentials and low electrolyte Mn(II) content. However, at high electrodeposition potentials and electrolyte Mn(II) contents, the crystal structure was only composed of hexagonal close packed ε-phase Zn-Mn. Corrosion measurements show that all the Zn-Mn samples have a passivating behavior and exhibits higher corrosion resistances when compared to those from aqueous solutions. Thus, optimum electrodeposition potential and electrolyte Mn(II) concentration were determined producing compact Zn-Mn films with the best corrosion resistance.

Microstructure and corrosion behavior of Cr and Cr–P alloy coatings electrodeposited from a Cr( iii ) deep eutectic solvent

Cr and Cr–P coatings were electrodeposited on Fe substrates from non-aqueous deep eutectic solvent-based electrolytes containing Cr(III). The optimized deposition parameters for the coating process were explored. A two-step process of Cr(III) reduction occurred, i.e. Cr(III) → Cr(II) → Cr(0), and the controlling step was promoted by adding NH4H2PO2. It was found that an electro-brush plated Ni underlayer was essential to obtain a smooth and compact Cr or Cr–P coating on the Fe substrate. The structure and composition of the as-deposited coatings were thoroughly analyzed. The corrosion behavior of the Cr and Cr–P coatings is quite different in 3.5 wt% NaCl and 0.1 M H2SO4 solutions. The diplex effects of the layered structures and ion-selective components in the as-prepared Cr-based coatings are suggested to be responsible for the different corrosion mechanism in different corrosion media.