Phosphorus-nitrogen co-doped graphene: Advancements in fast, highly sensitive ammonia sensing at room temperature

Abstract

High sensitivity and fast response ammonia gas sensors have wide applications in chemical production, food safety, medical diagnosis, and other fields. This work innovatively utilizes phosphorus and nitrogen as co-doping elements to significantly enhance the ammonia sensing performance of graphene. Ammonia sensing tests have shown that phosphorus-nitrogen co-doped graphene (PNG) exhibits excellent ammonia sensing performance at room temperature: high response (up to 4.34% response to 0.5 ppm ammonia, more than 5 times that of graphene), ultra-low detection limit (33.9 ppb), fast response/recovery (response time (${\text{T}}_{res}$) and recovery time (${\text{T}}_{rec}$) are 19 s and 36 s, respectively, which are more than 90% shorter than graphene on average). In addition, the PNG ammonia sensor also has excellent selectivity and good long-term stability. The PNG ammonia sensor studied in this paper has great potential in practical applications, especially in the detection of low concentration ammonia in exhaled breath analysis for medical diagnostics. It is expected to provide a reliable and low-cost solution for various applications of graphene ammonia sensors.