As an external field, a magnetic field can change the electrocatalytic activity of catalysts through various effects. Among them, electron spin polarization on the catalyst surface has attracted much attention. Herein, we investigate the sensitive response behavior of a Cu2O nanocubes to an in situ magnetic field. Under a 3 T strong magnetic field, the total transferred electron quantity in IT test (−1.1 VRHE) and the current density in the polarization curve increase by 28.7% and 54.7%, respectively, while the onset potential decreases significantly by 114 mV. Moreover, it was found that product selectivity was also altered by the magnetic field. The Faraday efficiency of C1 increases substantially, along with the inhibition of C2+ reaction paths and the HER. Our experimental results and DFT calculation demonstrate that a hybrid magnetic effect accelerates the CO2RR kinetic and generates spin polarization of the catalyst surface. The polarized surface changes the binding energy of *OCHO/*COOH and inhibits singlet C–C coupling, which restrains the C2+ reduction path and thus more CO2 is reduced to HCOOH.

Ruthenium dioxide-based electrocatalyst possesses the most potential in acidic oxygen evolution reaction (OER), however, most of them show low current density, low mass activity and unsatisfied stability under strong acidic...

Potassium‐ion batteries (PIBs) have attracted more and more attention as viable alternatives to lithium‐ion batteries (LIBs) due to the deficiency and uneven distribution of lithium resources. However, it is shown that potassium storage in some compounds through reaction or intercalation mechanisms cannot effectively improve the capacity and stability of anodes for PIBs. The unique anti‐spinel structure of magnetite (Fe3O4) is densely packed with thirty‐two O atoms to form a face‐centered cubic (fcc) unit cell with tetrahedral/octahedral vacancies in the O‐closed packing structure, which can serve as K+ storage sites according to the density functional theory (DFT) calculation results. In this work, carbon‐coated Fe3O4@C nanoparticles are prepared as high‐performance anodes for PIBs, which exhibit high reversible capacity (638 mAh g−1 at 0.05 A g−1) and hyper stable cycling performance at ultrahigh current density (150 mAh g−1 after 9000 cycles at 10 A g−1). In situ XRD, ex‐situ Fe K‐edge XAFS, and DFT calculations confirm the storage of K+ in tetrahedral/octahedral vacancies.