How Phosphorus Boosts Nickel-Iron's Oxygen Evolution

Scientists have long known that nickel-iron catalysts are great at producing oxygen from water, especially in alkaline conditions. But how they do it so well was a mystery—until now. A recent study looked at a special catalyst, nickel-iron phosphide (NiFeP), which is super active and stable. It only needs a small amount of extra energy to start the oxygen evolution reaction (OER). NiFeP's secret? Phosphorus. This element helps keep the active part of the catalyst, called β-Ni(Fe)OOH, stable. This stability is key to making the reaction happen smoothly. The study used special tools like Raman spectroscopy and electrochemical mass spectrometry to watch the reaction in action. They found that phosphorus helps the reaction by making it easier for certain steps to happen, like when hydroxide (OH) loses a hydrogen atom (deprotonation) and two oxygen atoms pair up (O-O coupling). This discovery is a big deal. It gives scientists a better understanding of how these catalysts work, which can help them design even better ones in the future.