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Ovsianytskyi, Oleksandr,Nam, Yun-Sik,Tsymbalenko, Oleksandr,Lan, Phan-Thi,Moon, Myoung-Woon,Lee, Kang-Bong Elsevier 2018 Sensors and actuators. B Chemical Vol.257 No.-
<P><B>Abstract</B></P> <P>Herein, we report a highly sensitive and selective H<SUB>2</SUB>S gas sensor based on graphene decorated with Ag nanoparticles (AgNPs) and charged impurities fabricated using a simple wet chemical method. Doping on as-grown chemical vapor deposited graphene was achieved by immersion in an aqueous solution of AgNO<SUB>3</SUB>/Fe(NO<SUB>3</SUB>)<SUB>3</SUB> for 4min followed by the decoration with adsorbed AgNPs and charged impurities. The AgNPs utilized in this process were formed by the reduction of Ag<SUP>+</SUP> ions, since the Ag<SUP>+</SUP>/Ag<SUP>0</SUP> reduction potential is higher than that of Fe<SUP>3+</SUP>/Fe<SUP>0</SUP>.</P> <P>The above treatment changed the electronic properties of graphene, achieving a dramatic resistivity change in the presence of H<SUB>2</SUB>S gas by generating surface sites for its adsorption and dissociation and thus allowing real time H<SUB>2</SUB>S level monitoring at ambient temperature with an immediate response.</P> <P>Doped graphene was demonstrated to selectively and repeatedly sense H<SUB>2</SUB>S gas within six minutes, with the limit of detection being below 100ppb. The corresponding mechanism is believed to feature a charge carrier density change of graphene to adsorbate charge transfer, with the sensor surface trapping or releasing electrons upon exposure to H<SUB>2</SUB>S gas.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Chemiresistive H<SUB>2</SUB>S sensor based on Ag nanoparticles doped-graphene was fabricated. </LI> <LI> Doping was performed in aqueous AgNO<SUB>3</SUB> and Fe(NO<SUB>3</SUB>)<SUB>3</SUB> by a simple wet-chemical method. </LI> <LI> The produced graphene sensor can detect ∼100ppb of H<SUB>2</SUB>S gas within 6min. </LI> <LI> The fabricated sensor exhibits excellent selectivity towards H<SUB>2</SUB>S gas. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>