Tuning the Catalytic Property of Phosphorene for Oxygen Evolution and Reduction Reactions by Changing Oxidation Degree.

The development of inexpensive metal-free catalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is highly desirable for fuel cells and rechargeable metal-air batteries. Black phosphorus (BP), as a new kind of two-dimensional (2D) layer material, has recently shown excellent OER electrocatalytic activity. However, atomistic understanding of the catalytic mechanism is lacking. Here, on the basis of ab initio calculations, we find that pristine phosphorene shows poor ORR/OER performances. However, oxidation can effectively tune the adsorption strength of reactive intermediates and thus change its OER/ORR electrocatalytic performance. For OER, the higher the local oxidation degree ( DlocalO) of phosphorene, the better the OER activity. Therefore, the oxidized phosphorene site with highest DlocalO shows the best OER catalytic property. In contrast, there exists an optimum DlocalO for ORR. These findings provide new insights for better understanding and improving the catalytic performances of BP-based electrocatalysts and could stimulate more theoretical and experimental studies in this area.