Palladium Coordination Polymers Nanosheets: New Strategy for Sensitive Photothermal Detection of H2S.

New strategies for portable detection of highly toxic environmental pollutants are still in urgent need. Here, through Pd2+ and methylene blue (MB) coordination, photothermal two-dimensional palladium coordination polymers nanosheets (2D PdCPsNSs) have been synthesized for sensitive photothermal detection of H2S. The sensing mechanism is based on the decomposing effect of H2S to 2D PdCPsNSs, accompanied by the decrease of PdCPsNSs concentration and the increase of MB concentration. Upon H2S addition, the heat released from the 2D PdCPsNSs under 808 nm lasers irradiation decreased, and the heat released from the MB increased under 650 nm lasers irradiation, respectively. Such temperature change signals could be easily detected by a portable thermometer. The 2D PdCPsNSs showed highly sensitive ratiometric response to H2S with a detection limit of 30 nM. In addition, such probe presents an excellent selective ratiometric response to H2S relative to other anionic species and thiols because of the specific interaction between Pd2+ and H2S. Moreover, the probe was suitable for the ratiometric determination of H2S in different actual water samples, providing a promising platform for convenient, stable, and universal analysis of H2S.