Density functional theory study of water adsorption on FeOOH surfaces

► Detailed density functional theory study of stability and properties of FeOOH surfaces and their interaction with water. ► Surface phase diagram within ab initio thermodynamics of goethite(101), akaganeite(100), and lepidocrocite(010) surfaces. ► Detailed structural information of the water/FeOOH interface including both molecular and dissociative adsorption modes. ► Dependence of reactivity and binding configuration on surface iron coordination. ► Control of Fe2 + to Fe3 + ratio at the FeOOH surfaces by surface terminal groups.