Magnetic field assisted electrocatalytic oxygen evolution reaction of nickel-based materials

Abstract

The dominant role of the magnetoresistance effect caused by spin electron scattering in the oxygen evolution reaction is unveiled through an in situ tunable magnetic field-electrochemical testing system.

Oxygen Evolution Reaction in Energy Conversion and Storage: Design Strategies Under and Beyond the Energy Scaling Relationship

“…As a result, the first electron transfer step was no longer the RDS. Analogously, Zhang and coworker also found that the magnetic field-induced spin-polarized kinetics was more distinct in the case that the first electron transfer step is the RDS during the OER [123]. With the projected density of states (PDOS) analysis, Ren and coworkers suggested that the spin alignment enabled a stronger 3d-2p hybridization in catalyst (Fig.…”

Magnetic Field Enhanced Electrocatalytic Oxygen Evolution of NiFe‐LDH/Co3O4 p‐n Heterojunction Supported on Nickel Foam

“…The above phenomenon, called magnetohydrodynamic (MHD) effect, is inclined to impair the thickness of the diffusion layer and enhance mass transfer, leading to reduced ohmic polarization, concentration polarization, and activation potential. [ 14d,31 ] However, the MHD effect is not the decisive factor leading to the enhancement of OER. According to previous studies, F L can accelerate the transport of charged species to enhance some electrochemical reactions, in which the reactants requiring long‐distance physical movement to the electrode‐electrolyte interface can be enhanced, such as the Cu deposition reaction.…”

“…Directly or indirectly, the magnetic effect has been proved positive in various electrochemical reactions, where the magnetohydrodynamic (MHD) effect, magnetothermal effect, spin polarization effect, and magnetoresistance (MR) effect are able to improve the diffusion, surface temperature of the catalysts, reaction path, and spin electrons transport efficiency, respectively. [ 14 ] Although preliminary progress has been made in magnetic field‐enhanced electrochemical reactions, many challenges remain to be solved. For example, typical magnetic materials with OER catalytic activity, including iron, cobalt, nickel, and various ferrites, more or less suffer from agglomeration, instability, and limited active sites.…”

Unveiling the Coercivity-Induced Electrocatalytic Oxygen Evolution Activity of Single-Domain CoFe2O4 Nanocrystals under a Magnetic Field

“…In addition, the magnetoresistance (MR) effect [MR = −p 2 μ 2 /(1 + p 2 μ 2 ), where p and μ are the spin polarization and the ratio of magnetization to saturation magnetization, respectively] has also been proposed as a key factor affecting the OER, which directly reflects the polarization rate of the spin electrons. 35,36 The MR of different CFO catalysts loaded on carbon cloth (identical to the electrochemical measurements) was measured on a physical property measurement system in the magnetic field range of The MR of all samples also decreases gradually with an increase in magnetic field intensity, with reduction percentages of 0.11% (CFO 3900 Oe), 0.12% (CFO 4500 Oe), 0.21% (CFO 6300 Oe), and 0.43% (CFO 7500 Oe), respectively. These results confirm that the electrocatalytic OER process on CFO catalysts can be efficiently enhanced by applying an external magnetic field, and the coercivity of CFO samples indeed plays a critical role in determining the degree of enhancement.…”

“…After application of a constant magnetic field of 14000 G, the Tafel slope is decreased by 6.7 (CFO 3900 Oe), 14.1 (CFO 4500 Oe), 40.7 (CFO 6300 Oe), and 61.8 mV decade −1 (CFO 7500 Oe), respectively (Figure 3a), suggesting the magnetic field accelerates the first electron transfer process and brings enhanced kinetics. 15,36 The variation trends of the Tafel slope and overpotential with coercivity are consistent; that is, the higher the coercivity, the more obvious the decrease. Therefore, the contribution of the magnetic field-promoted kinetics may be more significant with increasing coercivity, a notion that is confirmed by the decreased magnitude of R ct and MR (Figure 3b).…”