Turn the Trash into Treasure: Egg-White-Derived Single-Atom Electrocatalysts Boost Oxygen Reduction Reaction

Egg provides human beings the nutrition and economical products, such as antimicrobial and cosmetics. However, we mainly employ egg yolk, causing tons of egg white as the industrial waste to be further reprocessed. On account of the sustainable issue, we adopt the egg white to prepare single-atom electrocatalysts, achieving a half-wave potential (E1/2) of 0.927 V vs reversible hydrogen electrode (RHE) for oxygen reduction reaction, overperforming the commercial Pt/C (0.857 V) and the conventional iron single-atom electrocatalyst (0.835 V). Using in situ X-ray absorption spectroscopy (XAS) studies and density functional theory (DFT) calculations, we decrypt that electrons transfer through the dyz(dxz) orbitals in egg-white-derived single-atom electrocatalysts, facilitating their hybridization with the p orbital in oxygen, reducing the energy barrier in the rate-determining step, and boosting the overall catalytic activity. Our discovery provides an alternative perception to turn trash into treasure and promote sustainability.