Direct electro-phosphorization of nickel and cobalt films in hypophosphite solution for efficient hydrogen evolution

Study on the reaction kinetics of simultaneous recovery of iron phosphate from hypophosphite in perferite oxidation plating waste

Phosphorus is an indispensable and irreplaceable element in the ecosystem. Based on the ability of ferrate(VI) to remove phosphate by producing iron phosphate, a new method for using ferrate(VI) to treat hypophosphite has been studied. In this study, ferrate was added to the hypophosphate solution in a controlled manner, and the oxidation efficiency of ferrate(VI) on hypophosphate was studied under various initial pH conditions, when the pH value of 6.0, the hypophosphate oxidation rate reached 14.0%. Research findings, Ferrate recovered hypophosphate through precipitation and adsorption under various initial pH conditions. To further investigate the mechanism of hypophosphate recovery, the morphology and microstructure of the deposition were analysed using Fourier transform infrared, X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The kinetic process of ferrate recovery from hypophosphate was analysed. The recovery process follows second-order reaction kinetics, and the reaction rate is highest at pH 6.0. The value of kA1 is 1.742 × 10-2. This study shows that ferrate (VI) is a promising treatment tool for low-cost phosphate wastewater. Furthermore, this method offers a clean phosphorus recovery process without the generation of harmful substances.

Tailoring Cu Electrodes for Enhanced CO2 Electroreduction through Plasma Electrolysis in Non-Conventional Phosphorus-Oxoanion-Based Electrolytes

This study presents a green, ultra-fast, and facile technique for the fabrication of micro/nano-structured and porous Cu electrodes through in-liquid plasma electrolysis using phosphorous-oxoanion-based electrolytes. Besides the preferential surface faceting, the Cu electrodes exhibit unique surface structures, including octahedral nanocrystals besides nanoporous and microporous structures, depending on the employed electrolyte. The incorporation of P-atoms into the Cu surfaces is observed. The modified Cu electrodes display increased roughness, leading to higher current densities for CO2 electroreduction reaction. The selectivity of the modified Cu electrodes towards C2 products is highest for the Cu electrodes treated in Na2 HPO3 and Na3 PO4 electrolytes, whereas those treated in Na2 H2 PO2 produce the most H2 . The Cu electrode treated in Na3 PO4 produces ethylene (23 %) at -1.1 V vs. RHE, and a comparable amount of acetaldehyde (15 %) that is typically observed for Cu(110) single crystals. The enhanced selectivity is attributed to several factors, including the surface morphology, the incorporation of phosphorus into the Cu structure, and the formation of Cu(110) facets. Our results not only advance our understanding of the influence of the electrolyte's nature on the plasma electrolysis of Cu electrodes, but also underscores the potential of in-liquid plasma treatment for developing efficient Cu electrocatalysts for sustainable CO2 conversion.

In Situ Surface Restructuring of Amorphous Ni-Doped CoMo Phosphate-Based Three-Dimensional Networked Nanosheets: Highly Efficient and Durable Electrocatalyst for Overall Alkaline Water Splitting

Developing cost-efficient bifunctional electrocatalysts with high efficiency and durability for the production of green hydrogen and oxygen is a demanding and challenging research area. Due to their high earth abundance, transition metal-based electrocatalysts are alternatives to noble metal-based water splitting electrocatalysts. Herein, binder-free three-dimensional (3D) networked nanosheets of Ni-doped CoMo ternary phosphate (Pi) were prepared using a facile electrochemical synthetic strategy on flexible carbon cloth without any high-temperature heat treatment or complicated electrode fabrication. The optimized CoMoNiPi electrocatalyst delivers admirable hydrogen (η₁₀ = 96 mV) and oxygen (η₁₀ = 272 mV) evolution performances in 1.0 M KOH electrolyte. For overall water splitting in a two-electrode system, the present catalyst demands only 1.59 and 1.90 V to reach current densities of 10 and 100 mA/cm², respectively, which is lower than that of the Pt/C||RuO₂ couple (1.61 V @ 10 mA/cm², 2 V > @ 100 mA/cm²) and many other catalysts reported previously. Furthermore, the present catalyst delivers excellent long-term stability in a two-electrode system continuously over 100 h at a high current density of 100 mA/cm², exhibiting nearly 100% faradic efficiency. The unique 3D amorphous structure with high porosity, a high active surface area, and lower charge transfer resistance provides excellent overall water splitting. Notably, the amorphous structure of the present catalyst favors the in situ surface reconstruction during electrolysis and generates very stable surface-active sites capable of long-term performance. The present work provides a route for the preparation of multimetallic-Pi nanostructures for various electrode applications that are easy to prepare and have superior activity, high stability, and low cost.