Slow-release fertilizer encapsulated by graphene oxide films

• KNO3 pellets were encapsulated in graphene oxide (GO) films.
• Separated GO sheets fuse together to form a shell on KNO3.
• GO-coated KNO3 pellets exhibited slow-release behavior.

A slow-release fertilizer was developed by encapsulating KNO3 pellets with graphene oxide (GO) films. The material was then subjected to heat treatment, where adjacent GO sheets were soldered and reduced to reduced graphene oxide (re-GO) sheets by potassium. After the re-GO shell formed on KNO3 pellets, the slow-release characteristics of the fertilizer dramatically improved. The process of releasing fertilizer was prolonged to 8 h in water. We believe that this new coating technology could hold great promise for the development of environmentally-benign controlled-release fertilizer for crop production.