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Oxygen evolution reaction (OER), an important reaction involved in water splitting and rechargeable batteries, has drawn massive attention to clean energy generation, conversion, and efficient storage technologies during the last decades. However, noble metal-based highly active electrocatalysts for OER have been employed for water splitting, whereas their excessive cost and lethargic kinetics impede their usage. Bimetallic nanoparticles (NPs) have appeared as an essential class of catalysts suggesting higher catalytic efficiencies. Nickel/Iron (NiFe)-based compounds have been known as active OER catalysts by enormous commercial interest owing to their interesting mechanical, electrical, and corrosion-resistant properties. In this study, we prepared various Ni x Fe y nanoporous by reducing Ni and Fe precursors using a NaBH 4 reducing agent. The obtained catalysts show the high BET surface areas of 108.18, 122.67, 157.14, 166.65, and 244.12 (m2/g) for Ni, Ni 3 Fe 1 , Ni 1 Fe 1 , Ni 1 Fe 3 , and Fe samples; respectively. Among synthesized catalysts, it is obvious that Ni 3 Fe 1 exhibits a good OER performance with an overpotential of 220 mV or 346 mV at a current density of 10 mA. cm−2 or 50 mA. cm−2 and stability for 60,000 s due to the interaction between Ni and Fe and the exposure of more active surface area and low charge transfer electron resistance of the catalyst. This cheap and highly efficient Ni 3 Fe 1 electrocatalyst can be a promising candidate for the OER in water splitting for producing green fuel hydrogen. [Display omitted] • NiFe nanoporous materials are synthesized with large BET surface areas. • The presence of Fe enhances the BET surface area in bimetallic NiFe materials compared to pure Ni. • Electron density transfer between Ni and Fe atoms on the surface of the catalyst improves the OER activity. • Ni 3 Fe 1 shows the best OER activity during long-time operation. [ABSTRACT FROM AUTHOR]

One potential strategy to develop hydrogen evolution electrocatalysts for producing sustainable hydrogen in water electrolysis is creating electrocatalysts with low-cost, high activity, and high stability. Herein, we show that low-loading metal-based tungsten oxide (WO 3) can be used as electrocatalysts for the hydrogen evolution reaction (HER) in acid, alkaline, and alkaline-seawater electrolytes. Among prepared electrocatalysts, rhodium (Rh)-WO 3 exhibits a high HER activity with the values of overpotential of 48, 116, and 98 mV to obtain a current density of 10 mA cm−2 in acid, alkaline, and alkaline-seawater electrolytes, respectively. In addition, the Rh-WO 3 electrocatalyst shows high stability during the HER operation for over 60,000 s. Besides, the application of Rh-WO 3 electrocatalyst as cathode and commercial ruthenium oxide (RuO 2) as an anode for overall water splitting show excellent efficiency with only a potential of 1.45 V to a current density of 10 mA cm−2 in the alkaline-seawater electrolyte. The Rh-WO 3 //RuO 2 cell also exhibits high stability for over 80,000 s and maintains a current of 15 mA cm2 at a cell voltage of 1.51 V. The results provide evidence that Rh-WO 3 can be a promising HER catalyst for sustainable hydrogen production via alkaline-seawater electrolysis application. [Display omitted] • Low loading of Rh was synthesized on WO 3 nanosheets. • 5 wt% Rh-WO 3 exhibits excellent HER activity in the alkaline-seawater electrolyte. • The hydrogen spillover effect can improve the HER activity for the catalysts. • 5 wt% Rh-WO 3 as cathode shows the excellent water splitting process in the alkaline-seawater electrolyte. [ABSTRACT FROM AUTHOR]

Nanosized plasmonic metallic nanoparticles such as Pd have gained significant attention due to their diverse applications in catalysis, sensing, and light-to-heat conversion. However, the development of scalable and environmentally friendly synthesis routes for such nanoparticles is crucial for the sustainable development of industrial applications. In this work, we address this challenge by synthesizing Pd-nanoparticles on the cellulose filter paper (Pd-Cellulose) via two scalable green synthesis routes: low-temperature thermal and plasma synthesis. We found that adjusting synthesis conditions allowed us to achieve an optimum morphology that maximizes light absorptance. The nature of the reduction species during synthesis significantly impacts the morphology and heat-transfer properties of the resulting material. Compared to thermally synthesized Pd-Cellulose, the absorbers synthesized with plasma have smaller particles size and higher coverage, which leads to higher broadband light absorptance and more intense heat transfer to the surroundings. The optimized Pd-based light absorbers were utilized in a solar-to-steam desalination system, resulting in an evaporation rate of 1.30 kg/m2h for the open system and a filtration rate of 0.7 kg/m2h for the closed system. Our findings provide insights into the green and scalable synthesis and optimization of Pd-based light absorbers and their potential application in sustainable renewable energy systems. [Display omitted] • Pd-nanoparticles are synthesized via two synthesis routes: thermal and plasma synthesis. • The optimum morphology is achieved for maximized light absorptance. • The nature of the reduction species impacts the morphology and heat-transfer properties of nanoparticles. • A new lab-scale solar-to-steam desalination system with Pd-Cellulose is developed. [ABSTRACT FROM AUTHOR]

We report a novel cost-effective scaling process for the synthesis of the quinary IrPdPtRhRu high-entropy alloy nanoparticles (HEA-NPs). The process is based on the plasma ionic liquid reduction strategy. A combination of PXRD, HRTEM, XPS, and EDX analyses confirms that the application of the developed wet plasma reduction method yields the IrPdPtRhRu HEA-NPs. HEA-NPs ≈5 ​nm in size are synthesized under a mild temperature condition at atmospheric pressure and without support assistance. All elements constituting the as-prepared IrPdPtRhRu HEA-NPs are uniformly distributed in the FCC single-phase nanostructure. The valence band emission suggests the hybridization of the metal orbitals in the IrPdPtRhRu HEA-NPs. The work function (WF) of 4.63 ​eV for the HEA is determined by ultraviolet photoelectron spectroscopy. The WF value is lower than those of the metals constituting the HEA, suggesting higher catalytic activity. The IrPdPtRhRu/C electrocatalyst shows excellent catalytic performance toward hydrogen evolution reaction (HER) with an overpotential of 60 ​mV at a current density of 10 ​mA ​cm−2. A Tafel slope of 42 ​mV dec−1 is recorded in the alkaline electrolyte. The HEA electrocatalyst exhibits good long-term stability for 6 ​h without significant decay under a high constant current density of 100 ​mA ​cm−2. The findings in this study contribute to our basic scientific understanding of catalysts and provide a platform for the further development of HEA-NPs electrocatalysts for large-scale applications. [Display omitted] • Plasma ionic liquid reduction realizes IrPdPtRhRu HEA combinations for electrocatalyst. • HEA-NPs of 5 ​nm in size were synthesized under a mild temperature condition. • The valence band electronic structure suggests the hybridization of the metal orbitals in HEA-NPs. • The WF value of 4.63 ​eV, which is lower than that of each constituting element, suggests higher catalytic activity. [ABSTRACT FROM AUTHOR]