Composition Engineering of Amorphous Nickel Boride Nanoarchitectures Enabling Highly Efficient Electrosynthesis of Hydrogen Peroxide

Abstract Developing advanced electrocatalysts with exceptional two electron (2e − ) selectivity, activity, and stability is crucial for driving the oxygen reduction reaction (ORR) to produce hydrogen peroxide (H 2 O 2 ). Herein, a composition engineering strategy is proposed to flexibly regulate the intrinsic activity of amorphous nickel boride nanoarchitectures for efficient 2e − ORR by oriented reduction of Ni 2+ with different amounts of BH 4 − . Among borides, the amorphous NiB 2 delivers the 2e − selectivity close to 99% at 0.4 V and over 93% in a wide potential range, together with a negligible activity decay under prolonged time. Notably, an ultrahigh H 2 O 2 production rate of 4.753 mol g cat −1 h −1 is achieved upon assembling NiB 2 in the practical gas diffusion electrode. The combination of X‐ray absorption and in situ Raman spectroscopy, as well as transient photovoltage measurements with density functional theory, unequivocally reveal that the atomic ratio between Ni and B induces the local electronic structure diversity, allowing optimization of the adsorption energy of Ni toward *OOH and reducing of the interfacial charge‐transfer kinetics to preserve the OO bond.