Incorporation of single-atom copper into nitrogen-doped graphene for acetaminophen electrocatalytic degradation

Acetaminophen (APAP), as a pharmaceutical contaminant, can be degrade by electrocatalysis. However, the anode material is the main factor for electrocatalysis. Taking synergistic advantages of metal and graphene catalysts as anode is an effective way to improve the efficiency of electrocatalysis. Combining single metal atoms with graphene to maximize atom utilization efficiency of metal active center remains a challenge. This research fabricates single-atom copper (Cu) and nitrogen (N) atom-codoped graphene (1Cu@NG) as electrocatalytic anode. A series of characterizations disclose that the incorporation of N could be used as an anchor site for single-atom Cu, and the activity and stability of 1Cu@NG are optimized by interfacial interaction between single-atom Cu and N-doped graphene (NG). In 10 mg/L APAP with 1 g/L NaCl, the degradation efficiency of 1Cu@NG is 100 % within 90 min at current of 15 mA and leaching amounts of Cu ion is < 0.05 mg/L. The degradation efficiency of 1Cu@NG after four cycles is 97.13 % in 90 min and still maintain low ion leaching amounts (< 0.05 mg/L). The main active substances produced by 1Cu@NG in the electrocatalytic degradation process are O-2(center dot-) and active chlorine. In addition, the possible degradation pathways of APAP are explored.

Automated summary

Combining metal and graphene catalysts as anode can improve the efficiency of electrocatalysis in degrading pharmaceutical contaminants such as acetaminophen. This research successfully fabricates single-atom copper and nitrogen codoped graphene as an electrocatalytic anode, achieving maximum utilization efficiency of copper atoms and optimizing the activity and stability of the catalyst.