Niobium disulfide nanosheets modified surface plasmon resonance sensors for ultrasensitive detection of mercury ion

Abstract Mercury ion (Hg2+) can affect the quality of water and cause damage to human health. Therefore, the detection of Hg2+ in water, especially trace Hg2+, is very important. However, the detection limit (approximately 200 pM) of conventional Hg2+ sensors is far lower than the detection limit (7.5 pM) proposed by the US Environmental Protection Agency for measuring Hg2+. Here, we have developed a novel sensor based on niobium disulfide (NbS2)'s high perfect performance. The maximum value of SPR sensitivities approached to 193 °∕RIU achieved by coating the NbS2 nanosheets in simulation calculation, which had increased by 38.1% compared with the case without NbS2 overlayer. More importantly, this work also detected the ultra-low concentration of Hg2+ and describes the sensing mechanism of NbS2 based SPR sensors. Surprisingly, these sensors were used to detect mercury and the value of sensitivity is 13.55 °∕μM, and detection limit approach 1 pM. NbS2 nanosheets based SPR sensors provided innovative design ideas for the development of ultra-sensitive detection technology.