Efficient\nWater Oxidation at the Metal-Free, Phosphorus\nAcid-Functionalized Graphene Electrocatalytic Interface

The electrochemical oxygen evolution reaction (OER) is\ncurrently\none of the key challenges constraining the efficient conversion of\nelectricity into chemical fuels on a large scale. This is because\nthe OER must overcome a high electrochemical overpotential (thermodynamic\npotential) due to its complexity and the four protons and four electrons\nit involves. While noble-metal-based electrocatalysts can lower this\npotential, they are among the rarest metals in the Earth’s\ncrust, expensive, and not suitable for sustainable use. Herein, we\ndevelop a facile, cost-effective synthetic approach to an inexpensive,\nmetal-free OER electrocatalyst by preparing defective graphene nanosheets\nand then selectively functionalizing them with phosphorous acid species.\nThe electrocatalytic activity of the resulting metal-free, phosphorus-doped\n(P-doped) graphene toward OER surpasses those of previously reported\nmetal-free graphene-based electrocatalysts. Notably, the synthesized\ncatalyst requires a lower overpotential to catalyze the reaction,\nwhich can be attributed to its increased surface area and reactive\ndefect/active sites associated with the phosphorus dopants present\non it. The material also shows excellent stability, maintaining its\nperformance as well as its morphology and structures for hours in\nan alkaline electrolyte. The present work opens opportunities for\nthe design and synthesis of heteroatom-doped graphene (nanocatalyst)\nfor challenging environmentally benign, energy-related chemical transformations.