Surface Chemistry Determined Electrochemical Sensing Performance of Red Phosphorus and Single Walled Carbon Nanotube Composites

Abstract Red phosphorus (RP) is a promising electrochemical sensing material owing to its abundant surface groups and reactive sites. In this study, a sodium dodecyl sulfate‐assisted phosphorus‐amine approach is employed to tune surface chemistry of RP nanoparticles. During the transition of the polyphosphorus‐amine anion to RP, the cleavage of POP bond and the formation of POC bond are monitored by in situ attenuated total reflection surface‐enhanced infrared absorption spectroscopy. The formed POC bonds that are originated from the PO reactive sites are theoretically revealed with the density functional theory calculations, charge density difference, and X‐ray photoelectron spectroscopy. The energies of optimized aromatic and aliphatic POC bonds are −2.51 and −2.65 eV, respectively. To explore electrochemical sensing applications, RP nanoparticles are in situ grown on single‐walled carbon nanotube (SWCNT). Such a stable RP/SWCNT suspension is applied to fabricate the RP/SWCNT integrated arrays via a template‐filtration method. Such an array is efficient for sensitive and selective monitoring of p‐phenylenediamine on hair dyes. This study provides insights into surface chemistry of RP, its roles in electrochemical sensing applications, and an approach to produce high‐performance RP sensors at large scales.