Premagnetized Carbon-Catalyst Interface Delivering 650% Enhancement in Electrocatalytic Kinetics of Hydrogen Evolution Reaction

Manipulating heterogeneous electrified interfaces with an external magnetic field (Hext) explicitly mandates the constant presence of Hext for achieving magnetoelectrocatalytic kinetic enhancements. Here, we demonstrate the highest kinetic enhancement of 650% in electrocatalytic hydrogen evolution reaction (HER), without the mandatory presence of Hext. A synergistic interface created in nanostructured hard carbon florets (NCF) decorated with ferro–paramagnetic nanoparticles (Co3O4, Co, and Ni–Co) is demonstrated to be critical for both (a) prominent enhancement in HER-kinetics when Hext = 200 mT and (b) sustaining the rapid HER when Hext = 0 mT. Significant lowering of magnetoresistance (22%) and magnetocharge-transfer resistance (84.8%) using a weak Hext = 100 mT leads to a 2.5-fold volumetric increment in hydrogen generation driven by 7% enhancement in electrokinetic activity. Furthermore, all such enhancements are strongly correlated with the magnetic coercivity of the catalyst, implying the role of interfacial mechanistic modulation of the HER by Hext. Additionally, microscopic dimensional enlargement of the structurally flexible NCF promotes such a long-term effect leading to larger magnetocurrent as compared to other carbon-based supports. Our work demonstrates the importance of spin polarization in magnetically active electrocatalytic interfaces and thereby offers a general practical strategy for energy-efficient hydrogen production.