Implementing sensitive and fast ppb-level formaldehyde sensing at room temperature is still extremely demanded for practical indoor air quality monitoring. Herein, we developed a visible-light sensitive and dipole modified graphene-based...

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.

No abstract

Carbon dots (CDs) are a promising fluorescent material in biological and optoelectronic applications owing to their high biocompatibility, low cytotoxicity, and high stability. Red emission CDs are not only widely...

Graphene foams are promising three-dimensional (3D) architectures with the combination of the intrinsic nature of graphene and unique cellular structures for various realms. Herein, a facile technique is developed by combining supramolecular assembly with lyophilization to functionalize graphene with donor−π-acceptor (D−π-A) molecules and then massively transform the two-dimensional (2D) plane nanosheets into 3D foams. The as-prepared gas sensors work at room temperature (RT) and reveal comprehensive gas sensing performance with an ultrahigh response (R a/R g = 3.2, 10 ppm), excellent selectivity, and reliable repeatability toward NO2. Notably, a gas sensing enhancement mechanism with density functional theory (DFT) calculations is proposed to unravel the synergetic effect of the “Greater Electron Transferring Area” and the specific 3D foam structure for the enhancement of charge transfer and NO2 adsorption. The combination of supramolecular assembly and the lyophilization technique provides a strategy to prepare 3D architectural graphene-based materials for high-performance gas sensors and chemical trace detectors.