凯发

The development of clean and sustainable energy conversion and storage systems with a high efficiency and low cost, such as fuel cells and metal-air batteries, has become more important than ever. Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are at the heart of the energy techniques. However, these reactions are sluggish. To counter the problem, electrocatalysts are commonly used to lower the energy barriers of these reactions and boost boost the performance of the energy systems in terms of energy efficiency and rate capacity. Noble metal catalysts (e.g. Pt/C) have good catalytic activities, but are expensive and hold back the commercialization of fuel cells Researchers have been trying to replace/complement the precious metal catalysts. 

Graphene and other graphitic carbons provide ideal platforms to modulate the electrocatalytic activities of carbon-based catalysts. Our recent effort exhibits that the electrocatalytic activities of graphitic carbons for ORR and OER can be enhanced by modifying the surface/interface structures via functionalization and heteroatom doping. Typically, the graphene-based electrocatalysts with good catalytic activities for ORR have been prepared by via a chelation-mediated aqueous method (Fig.1a), exhibiting the promising application in fuel cells. Besides, the theoretical predication reveals that both ORR and OER are able to be enhanced by modifying the surface structures of graphene with nitrogen and phosphorous. Thus, the three-dimensional graphene (Fig.1b) and porous graphitic carbons co-doped with nitrogen and phosphorous have been prepared by low-cost, scalable methods and investigated as efficient bifunctional electrocatalyts. More importantly, Zn-air batteries with high performance have been fabricated by using the as-prepared electrocatalysts. The works would be helpful to design novel carbon-based electrocatalysts for fuel cell and others.