Se-Doped Magnetic Co–Ni Spinel Ferrite Nanoparticles as Electrochemical Catalysts for Hydrogen Evolution

Abstract

The magnetic Co 0.5 Ni 0.5 Fe 2 O 4 spinel ferrites (NSFs) with various (x%) Se (x = 0.00−0.20) were synthesized via the sol−gel combustion route in conjunction with an advanced green laser ablation method. The structure and morphology of NSFs were explored through various physicochemical techniques. Interestingly, Se doping has a crucial impact on NSFs' magnetic properties. While, at room temperature, the pristine sample exhibits a superparamagnetic-like behavior, the pristine sample and all doped CoNi NSFs + x% Se (x = 0.05−0.20) samples exhibited a high value of coercivity and remanence at 10 K, indicating their hard magnetic properties. Our findings indicate that Se can be harnessed to tune the magnetic properties of CoNiFe 2 O 4 structures. In addition, improving effective electrocatalysts for hydrogen evolution reaction (HER) efficiency through water splitting is also vital to overcoming the impending energy crisis due to the rapid depletion of fossil fuels and their injurious impact on the environment. Hence, the optimized ideal catalysts CoNi NSFs + x% Se (x = 0.15) were developed, which outperformed as electrocatalysts for HER with a Tafel slope of 91 mV/dec and a very low overpotential of 173.5 mV at a current density of 10 mA/ cm 2 , which could be attributed to a large number of electrochemically active surface area (5.2 cm 2 ), accelerated electron mobility at the electrocatalysts/electrolyte interface, and long-term stability.

Chestnut-like Molybdenum-Doped Nickel Cobaltite Spinel Oxide Nanoparticles Grown on Ni Foam as the Electrocatalyst for the Hydrogen Evolution Reaction

“…The ECSA histogram depicted in Figure f indicates that introducing Mo doping into the NiMo x Co 2– x O 4 CNSP electrode results in a considerable increase in ECSA compared to the unmodified NiCo 2 O 4 electrode. The introduction of Mo doping has the potential to alter the electron distribution and impede the surface oxidation of NiCo 2 O 4 , leading to an increase in the availability of active sites and ultimately promoting the efficacy of the HER process . Nevertheless, an overabundance of Mo doping in NiCo 2 O 4 CNSPs could potentially hinder the active sites and function as a recombination center due to alterations in the structure and composition .…”

“…The Tafel slope has been widely employed to investigate the rate-determining steps in the HER mechanism process for enhanced comprehension. The Volmer, Heyrovsky, and Tafel reactions are widely recognized as the three primary steps involved in converting hydrogen protons into molecular hydrogen. ,,,, Based on the underlying mechanisms, the amalgamation of the Volmer pathway alongside either the Heyrovsky or Tafel pathway could produce molecular hydrogen. Typically, when the slope is approximately 120 mV/dec, the Volmer step mechanism is the reaction rate’s limiting factor.…”

“…The electrodes’ catalytic efficacy − was assessed through linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), Tafel slopes, electrochemically active surface area (ECSA), cyclic voltammetry (CV), C dl (electrochemical double-layer capacitance), roughness factor (RF), specific activity (SA), “ n ” (surface-active sites), and chronopotentiometry (CP) analysis (1 M KOH solution). The detailed calculations and procedures are incorporated in the Supporting Information.…”

In Situ Growth of Interfacially Nanoengineered 2D–2D WS2/Ti3C2Tx MXene for the Enhanced Performance of Hydrogen Evolution Reactions

“…In order to better understand the best electrocatalyst (5% WS 2 −MXene) that showed the best activity with respect to its other counterparts, electrochemical surface area (ECSA) and double-layer capacitance (C dl ) were determined. 55 Cyclic voltammetry (CV) in the nonfaradaic region was employed in Figure S(8)at various scan rates ranging from 10 to 100 mV s −1 . The calculated C dl values of 5% WS 2 −MXene, MXene, and WS 2 are presented in Figure 5d.…”

Effective Hydrogen Production from Alkaline and Natural Seawater using WO3–x@CdS1–x Nanocomposite-Based Electrocatalysts

“…The incessant rise of environmental pollution, climate change, and energy crises has compelled humanity to seek energy resources that possess abundance, affordability, cleanliness, ecological friendliness, and sustainability. In light of this, hydrogen has emerged as a prospective fuel for the future, offering the potential to address various challenges associated with environmental and energy crises. , It is established that hydrogen can efficiently be produced at low cost via the electrolysis of water, offering a versatile resource of renewable energy like solar and wind . Research revealed that the alkaline electrocatalytic hydrogen evolution reaction (HER) is preferable with acidic and neutral electrolytes because of less corrosion for equipment and transition metal-based electrodes.…”