Lattice Strained B-Doped Ni Nanoparticles for Efficient Electrochemical H2 O2 Synthesis.

ABSTRACT

Surface strains are necessary to optimize the oxygen adsorption energy during the oxygen reduction reaction (ORR) in the four-electron process, but the surface strains regulation for ORR in the two-electron process to produce hydrogen peroxide (H2 O2 ) is rarely studied. Herein, it is reported that the tensile strained B-doped Ni nanoparticles on carbon support (Ni-B@BNC) could enhance the adsorption of O2 , stabilize OO bond, and boost the electrocatalytic ORR to H2 O2 . Moreover, the Ni-B@BNC catalysts exhibit volcano-type activity for electrocatalytic ORR to H2 O2 as a function of the strain intensity, which is controlled by B content. Among them, Ni4 -B1 @BNC exhibits the highest H2 O2 selectivity of over 86%, H2 O2 yield of 128.5 mmol h-1  g-1 , and Faraday efficiency of 94.9% at 0.6 V vs reversible hydrogen electrode as well as durable stability after successive cycling, being one of the state-of-the-art electrocatalysts for two-electron ORR. The density functional theory calculations reveal that tensile strain introduced by doping B into Ni nanoparticles could decrease the state density of Ni-3d orbital and optimize the binding energy of OOH* during ORR. A new direction is provided here for the design of highly active and stable catalysts for potential H2 O2 production and beyond.