CarbonIron Electron Transport Channels in Porphyrin–Graphene Complex for ppb‐Level Room Temperature NO Gas Sensing

Abstract

It is a great challenge to develop efficient room‐temperature sensing materials and sensors for nitric oxide (NO) gas, which is a biomarker molecule used in the monitoring of inflammatory respiratory diseases. Herein, Hemin (Fe (III)‐protoporphyrin IX) is introduced into the nitrogen‐doped reduced graphene oxide (N‐rGO) to obtain a novel sensing material HNG‐ethanol. Detailed XPS spectra and DFT calculations confirm the formation of carbon–iron bonds in HNG‐ethanol during synthesis process, which act as electron transport channels from graphene to Hemin. Owing to this unique chemical structure, HNG‐ethanol exhibits superior gas sensing properties toward NO gas (Ra/Rg = 3.05, 20 ppm) with a practical limit of detection (LOD) of 500 ppb and reliable repeatability (over 5 cycles). The HNG‐ethanol sensor also possesses high selectivity against other exhaled gases, high humidity resistance, and stability (less than 3% decrease over 30 days). In addition, a deep understanding of the gas sensing mechanisms is proposed for the first time in this work, which is instructive to the community for fabricating sensing materials based on graphene‐iron derivatives in the future.

Synthesis of Graphene-Based Nanocomposites for Environmental Remediation Applications: A Review

“…These divalent metal ions act as a cross-linking building block between two adjacent carboxyl moieties of the GO layers and increase their solidity as well as stability. GO can also form composites when blended with carbon nanotubes, metal and their oxides, polymers, and some organic molecules, which work as spacers to prevent GOs restacking and helps in making the graphene material more porous [ 168 , 169 , 170 , 171 , 172 , 173 ].…”

Assembly of Core/Shell Nanospheres of Amorphous Hemin/Acetone-Derived Carbonized Polymer with Graphene Nanosheets for Room-Temperature NO Sensing

“…GO was synthesized by a modified Hummers' method following the procedure reported in our previous work. 18 The measured concentration of GO was 5 mg/mL.…”

“…In general, rGO exhibited p-type semiconducting behavior whose resistance will reduce along with the increase of hole concentration. 16,18 As shown in Figure 5, NO molecules absorbed onto the surface of HNS could contact with the Fe 3+ ion of the Fe−N 4 moiety through the hole of the acetone layer. Afterward, electrons are transferred from graphene to Fe 3+ , and subsequently given to the NO molecules benefiting from the strong electronegativity of NO.…”

“…15−17 In 2022, we found that assembling Hemin (Fe (III)-protoporphyrin IX) molecules onto the surface of graphene nanosheets will realize parts per billion-level NO sensing at RT with a limit of detection (LOD) of 500 ppb. 18 The Fe−N 4 active sites of Hemin molecules have the specific response to NO at RT. Unfortunately, most of the Hemin molecules will tend to form dimers via Fe−O coordination bonding and crystallize through hydrogen bonding between dimers as reported in that work.…”

Hemin functionalized hybrid aerogel-enabled electrochemical chip for real-time analysis of H2O2

“…Hemin, as a kind of metalloporphyrin, possesses outstanding enzyme-like bioactivity 20 and shows good potential for application in electrochemical sensing. 21,22 However, independent nano-sized hemin catalysts may suffer from agglomeration. To avoid such a problem, a promising approach is to fix such catalysts to other matrix materials.…”