Highly Surface Active Phosphorus-Doped Onion-Like Carbon Nanostructures: Ultrasensitive, Fully Reversible, and Portable NH₃ Gas Sensors

Abstract

Unique phosphorus-doped onion-like carbon nanostructures (P-OLCs) with superior surface properties have been synthesized through a temperature and pressure controlled thermal decomposition method. The substitutional doping of phosphorus in onion-like carbon nanostructures (OLCs) could facilitate the charge transfer during ammonia gas sensing. The presence of polar metaphosphates/phosphonate species in the active sites of highly crystalline P-OLCs due to interstitial doping of oxygen incorporated with substitutionally doped phosphorus atoms significantly enhanced the sensitivity with fast response and recovery characteristics (2.8 and 4.5 s) toward NH3 at room temperature. Further, ammonia gas adsorption kinetics in OLCs and P-OLCs have been meticulously investigated, which revealed the faster adsorption rate in P-OLCs (2.17 × 10–7 Ω–1s–1) compared to pristine OLCs (8.599 × 10–8 Ω–1s–1). This method can widely open up the feasibility to induce enhanced surface activity (phosphorus-containing groups allow the access of oxygen to the carbon lattice) by phosphorus doping in OLCs for gas sensing and other microelectronics device applications.

Carbon Nanomaterials: Synthesis, Functionalization and Sensing Applications

“…The electrode showed a linear enhanced amperometric responses towards hydrogen peroxide in the range from 1.0 × 10 −7 to 6.1 × 10 −3 M. In addition, the electrode showed a fast response of 1 s achieving the 95% of the steady-current in presence of hydrogen peroxide. Phosphorus doped CNOs are utilized to fabricate highly sensitive devices for NH 3 [183]. The sensing mechanism is based on chemisorbed oxygen on the P-doped CNOs resulting in a charge transfer from C atoms to oxygen atoms.…”

“…The detection limit of this mechanism is 1.3 × 10 −2 M. Glucose was detected also using an amperometric sensing approach coupling CNOs to CNTs [188] or to Pt nanoparticles [189]. [183]. (B) Glucose sensor based on the optical properties of CNOs: addition of methylene blue quenches the natural emission from CNOs.…”

“…The hybridization of the target DNA with the DNA sequence of the papilloma virus can be detected by amperometric measurements [190]. Reprinted with permission from [183][184][185]190]. Copyright: 2019 American Chemical Society; 2018 Elsevier, 2016 RSC Publishing and 2009 Elsevier respectively.…”

“…CNOs and CNOs-CNF gave comparable electrocatalytic activities in terms of sensitivity and LOD (CNOs 1.23 μM and sensitivity of 0.74 μA/μM, and CNOs-CNF 1.42 μM, 0.31 μA/μM). Surface of oxidized CNOs [183]. (B) Glucose sensor based on the optical properties of CNOs: addition of methylene blue quenches the natural emission from CNOs.…”

“…Figure 9. (A) electrochemical sensor based on CNOs: charge transfer between CNOs and NH 3 molecules results in a change of the sensor resistance thus enabling detection of ammonia gas[183]. (B) Glucose sensor based on the optical properties of CNOs: addition of methylene blue quenches the natural emission from CNOs.…”