A highway for proton desorption and migration mediated by H2PO4− groups through robust interfacial hydrogen bond network to enhance the kinetic activity of oxygen evolution reaction

The sluggish kinetics of both proton dissociation and proton migration during OER is identified as the key bottleneck. • High-pKa H 2 PO 4 − groups are incorporated into NiFe LDH to upshift the d-band center and optimize electronic structure. • H 2 PO 4 − groups function as proton ferry to facilitate O H bond cleavage and reduce the energy barrier. • A proton highway is constructed via the Grotthuss mechanism by mediating a hydrogen-bond-rich microenvironment. • Synergistic promotion of proton dissociation and migration leads to outstanding OER activity and stability. Alkaline water electrolysis represents a promising strategy for sustainable hydrogen production. However, its energy efficiency is significantly constrained by the inherently sluggish kinetics of proton dissociation and proton migration during oxygen evolution reaction (OER). To address this limitation, the H 2 PO 4 − groups with high pKa value were reasonably incorporated into the lattice of NiFe-layered double hydroxide (P-NiFe LDH), thus optimizing the electronic structure by upshifting the d -band centre to improve the mass transfer. Additionally, the H 2 PO 4 − groups also functioned as proton ferry groups, which facilitated the cleavage of O H bonds in key intermediates to reduce the energy barrier. The in-situ Raman spectra and DFT calculations further confirmed that the H 2 PO 4 − groups mediated the microenvironment rich in hydrogen bond network, thus constructing a highway for proton transport via the Grotthuss mechanism. Ultimately, the P-NiFe LDH demonstrated exceptional activity toward water oxidation, requiring only an overpotential of 283 mV at the current density of 100 mA cm −2 , while maintaining remarkable stability for over 50 h at 10 mA cm −2 . This work not only highlights the importance of synergistically promoting the process of proton dissociation and proton migration in OER, but also provides valuable insights for the design of high-performance OER electrocatalysts.