Short Hydrogen Bonds on Reconstructed Nanocrystal Surface Enhance Oxygen Evolution Activity

Water splitting to generate hydrogen and oxygen gas is critical to renewable energy technologies, including fuel cells and rechargeable metal–air batteries. The oxygen evolution reaction (OER) has long been the bottleneck of water splitting because of its high overpotential (η) and sluggish kinetics, and development of efficient, stable, and non-noble-metal-based OER catalysts has been an extensively studied topic. Here, we propose short hydrogen bonds on reconstructed nanocrystal surface to enhance oxygen evolution activity by investigating three types of phase structures (β_II, β_I, and γ₀) of Li₂CoSiO₄ (LCS) nanoparticles as OER electrocatalysts. Among them, the β_II-LCS outperforms the previously reported Co-based catalysts and the state-of-the-art IrO₂ catalyst for OER in the alkaline condition. Our experiments combined with ab initio calculations indicated that due to the line-linked arrangement of Co active sites at the surface of β_II-LCS, short hydrogen bonds (2.54 Å) are formed and linked into a network at the reconstructed surface by rotating the flexible CoO₄ tetrahedra after surface delithiation, thus facilitating proton transfer and dissociation, leading to a unique dual-center catalytic pathway with low theoretical thermodynamic overpotential (0.35 eV) for the OER process