Morphology-controllable nanocrystal β-Ni(OH)2/NF designed by hydrothermal etching method as high-efficiency electrocatalyst for overall water splitting

Optimized Transition Metal Phosphides for Direct Seawater Electrolysis: Current Trends

Seawater electrolysis presents a viable route for sustainable large-scale hydrogen production, yet its practical application is hindered by several technical challenges. These include the sluggish kinetics of hydrogen evolution, poor stability, cation deposition at the cathode, electrode corrosion, and competing chloride oxidation at the anode. To overcome these obstacles, the development of innovative electrocatalysts is crucial. Transition metal phosphides (TMPs) have emerged as promising candidates owing to their superior catalytic performance and tunable structural properties. This review provides a comprehensive analysis of recent progress in the structural engineering of TMPs tailored for efficient seawater electrolysis. We delve into the catalytic mechanisms underpinning hydrogen and oxygen evolution reactions in different pH conditions, along with the detrimental side reactions that impede hydrogen production efficiency. Several methods to prepare TMPs are then introduced. Additionally, detailed discussions on structural modifications and interface engineering tactics are presented, showcasing strategies to enhance the activity and durability of TMP electrocatalysts. By analyzing current research findings, our review aims to inform ongoing research endeavors and foster advancements in seawater electrolysis for practical and ecologically sound hydrogen generation.

Molybdenum and Vanadium-Codoped Cobalt Carbonate Nanosheets Deposited on Nickel Foam as a High-Efficient Bifunctional Catalyst for Overall Alkaline Water Splitting

To address issues of global energy sustainability, it is essential to develop highly efficient bifunctional transition metal-based electrocatalysts to accelerate the kinetics of both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Herein, the heterogeneous molybdenum and vanadium codoped cobalt carbonate nanosheets loaded on nickel foam (VMoCoCOx@NF) are fabricated by facile hydrothermal deposition. Firstly, the mole ratio of V/Mo/Co in the composite is optimized by response surface methodology (RSM). When the optimized composite serves as a bifunctional catalyst, the water-splitting current density achieves 10 mA cm-2 and 100 mA cm-2 at cell voltages of 1.54 V and 1.61 V in a 1.0 M KOH electrolyte with robust stability. Furthermore, characterization is carried out using field emission scanning electron microscopy-energy dispersive spectroscopy (FESEM-EDS), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Density functional theory (DFT) calculations reveal that the fabricated VMoCoCOx@NF catalyst synergistically decreases the Gibbs free energy of hydrogen and oxygen-containing intermediates, thus accelerating OER/HER catalytic kinetics. Benefiting from the concerted advantages of porous NF substrates and clustered VMoCoCOx nanosheets, the fabricated catalyst exhibits superior electrocatalytic performance. This work presents a novel approach to developing transition metal catalysts for overall water splitting.

Recent Advances in One-Dimensional Micro/Nanomotors: Fabrication, Propulsion and Application

Due to their tiny size, autonomous motion and functionalize modifications, micro/nanomotors have shown great potential for environmental remediation, biomedicine and micro/nano-engineering. One-dimensional (1D) micro/nanomotors combine the characteristics of anisotropy and large aspect ratio of 1D materials with the advantages of functionalization and autonomous motion of micro/nanomotors for revolutionary applications. In this review, we discuss current research progress on 1D micro/nanomotors, including the fabrication methods, driving mechanisms, and recent advances in environmental remediation and biomedical applications, as well as discuss current challenges and possible solutions. With continuous attention and innovation, the advancement of 1D micro/nanomotors will pave the way for the continued development of the micro/nanomotor field.

Self-supported Ni3S2@Ni2P/MoS2 heterostructures on nickel foam for an outstanding oxygen evolution reaction and efficient overall water splitting

Hydrogen production by electrocatalytic water splitting is a pollution-free, energy-saving, and efficient method. The low efficiency of hydrogen production, high overpotentials and expensive noble-metal catalysts have limited the development of hydrogen production from electrocatalytic water splitting. Therefore, the exploration of bifunctional electrocatalysts for water overall splitting to produce hydrogen is of profound significance. Herein, Ni₃S₂@Ni₂P/MoS₂ heterostructure electrocatalysts were synthesized on Ni foam through an environmentally friendly hydrothermal method and low-temperature phosphating method. The synergistic effects between different components and the mutual substitution principle between sulfur atoms and phosphorus atoms greatly improve the OER performance of the electrocatalyst. It is also an effective strategy to optimize the adsorption energies of intermediates by the design of heterostructured catalysts composed of multiple substances. Ni₃S₂@Ni₂P/MoS₂ only requires a low overpotential (η₁₀) of 175 mV at a current density of 10 mA cm^-2 in 1.0 M KOH solution and the stable duration exceeds 40 h. In addition, this heterogeneous structure is assembled into an electrolytic cell for overall water splitting, which exhibits a low cell voltage of 1.61 volts and retains the robust stability over 30 h at 10 mA cm^-2. The Ni₃S₂@Ni₂P/MoS₂ heterostructure prepared in this research provides a strategy for exploring other heterostructured electrocatalysts with different components.