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The current two-dimensional (2D) material based NH 3 sensors generally suffer from low response values and sluggish recovery dynamics, which is resulted from their inferior conductivity. Herein, high conductivity (0.045 S/m) of 2D hydrogen substituted graphyne (HsGY) nanosheets are successfully synthesized employing aqueous/organic interface method and using them for the first time for the detection of NH 3 at room temperature. The resultant gas sensing performance shows that the 2D HsGY nanosheets exhibit a high gas response value (4.9) to 100 ppm NH 3 and fast recovery time (108 s) at the room temperature. The NH 3 gas sensing mechanism is discussed by utilizing density functional theory (DFT) calculations. The present study provides novel gas sensing material for the development of high-performance room temperature NH 3 sensors. This study successfully synthesized two-dimensional hydrogen substituted graphyne (HsGY) nanosheets using an aqueous/organic interface method and applied them for the detection of NH 3 at room temperature for the first time. HsGY nanosheets exhibit excellent sensing performance towards NH 3 , due to their high conductivity and continuous thin gauze like morphology, which facilitates gas transport. [Display omitted] [ABSTRACT FROM AUTHOR]

• The flower-like TiO 2 microspheres were synthesized by a tunable tetrabutyl titanate-assisted hydrothermal method. • The as-made gas sensors showed high sensitivity and selectivity to NH 3 at the room temperature. • The underlying mechanism for the high selectivity to NH 3 was discussed using DFT calculations. TiO 2 is proved to be a promising material in the detection of various hazardous gases at the high temperature. However, gas adsorption-diffusion capacity at the room temperature is limited by their insufficient specific surface area and surface active sites. Herein, we report a strategy to synthesis of flower-like TiO 2 microspheres assembled by nanosheets and characterize the selective adsorption of NH 3 by using density functional theory (DFT). The as fabricated flower-like TiO 2 microspheres show an outstanding gas sensitivities (∼122 to 50 ppm NH 3) and high selectivity for NH 3 detection at room temperature. The higher adsorption energy and smaller adsorption distance of NH 3 on TiO 2 (001) indicate the much stronger interaction NH 3 -TiO 2 system. The present studies provide useful gas sensing materials with fine morphologies for the development of high-performance room temperature NH 3 sensors. [ABSTRACT FROM AUTHOR]