Improving Gas Sensing Performance of Hydroxyapatite by Incorporating Black Phosphorene

In this work, short rod-shaped hydroxyapatite (HA) nanocrystals were synthesized by hydrothermal method, and black phosphorene (BP) was prepared by ultrasonication of black phosphorous and modified by pyrrole. Different mass ratios (3%, 5%, 7%, 10%) of BP were mechanically mixed with HA to prepare BP/HA hybrid. The structure, morphology and composition of the as-synthesized hybrid were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy and Raman spectroscopy. The gas sensing properties were studied using a chemical gas sensing system. It is found that the incorporation of BP greatly improves the sensing response of HA to ammonia, and 7% BP, HA has the best sensing performance. Its sensing response for 100 ppm ammonia is as high as 42.3%, which is 2.75 times that of pure HA. For 1000 ppm ammonia, the response can achieve 91%. BP/HA exhibits shorter response time, good selectivity, reproducibility and long-term stability to ammonia. These results indicate that BP HA hybrid is a promising sensing material for ammonia at room temperature. The mechanism for the enhancement of the response to ammonia is also discussed.