Sandwiching Phosphorene with Iron Porphyrin Monolayer for High Stability and Its Biomimetic Sensor to Sensitively Detect Living Cell Released NO

Instability of 2D phosphorene material is the major obstacle for its broad applications. Herein phosphorene is sandwiched with self‐assembled iron porphyrin monolayers on both sides (I‐Phene) to significantly enhance stability. Iron porphyrin has strong interaction with phosphorene through formation of PFe bonds. The sandwich structure offers excellent stability of phosphorene by both‐sided monolayer protections for an intact phosphorene structure more than 40 days under ambient conditions. Meanwhile, the electron transfer between iron porphyrin and phosphorene result in a high oxidation state of Fe, making I‐Phene biomimetic sensitivity toward oxidation of nitric oxide (NO) for 2.5 and 4.0 times higher than phosphorene and iron‐porphyrin alone, respectively. Moreover, I‐Phene exhibits excellent selectivity, a wide detection range, and a low detection limit at a low oxidation potential of 0.82 V, which is comparable with the reported noble metal based biomimetic sensors while ranking the best among all non‐noble biomimetic ones. I‐Phene is further used for real‐time monitoring NO released from cells. This work provides effective approach against phosphorene degrading for outstanding stability, which has universal significance for its various important applications, and holds a great promise for a highly sensitive biomimetic sensor in live‐cell assays. A sandwich structure of phosphorene assembled with iron porphyrin exhibits enhanced stability under ambient conditions which overcomes drawback of phosphorene. The sandwiched material acts as a biomimetic catalyst for high‐performance NO sensing, realizing in situ monitoring NO in live‐cell assays.