Fig. 3: Mechanisms of hBN film catalyzed OER reactions.
From: One-atom-thick hexagonal boron nitride co-catalyst for enhanced oxygen evolution reactions
a Current density measured in KOH with pH = 11.15, 12.05, 12.90, 13.16, 13.42, and 13.65, for curves from bottom to top. These pH values correspond to KOH solution concentrations of 0.001 M, 0.01 M, 0.1 M, 0.2 M 0.5 M, and 1 M, respectively. Inset shows OER current density at 1.72 V versus RHE plotted in log scale as a function of pH. The red line shows the proton reaction order prediction using ρRHE = ∂log j/∂pH = 1. b LSV curves for hBN/NiFeOxHy electrodes measured in 1 M KOH (dissolved in H2O) and KOD (dissolved in D2O) solutions. Inset shows the kinetic isotope effect. jKOH and jKOD are the current densities measured in KOH and KOD, respectively. c Gibbs free energy diagrams of the hBN catalyzed OER reactions. Top left inset shows the charge transfer between hBN and NiFeOxHy layers, with yellow and cyan clouds showing electron accumulation and depletion near atoms, respectively. Other insets show the simulated reaction processes. The rate-determining step is marked by the red line.
