Ni-Co-P hollow nanobricks enabled humidity sensor for respiratory analysis and human-machine interfacing

Metal phosphide has been widely exploited in the field of energy storage and catalysis instead of chemical sensors. In this work, Ni-Co-P hollow nanobricks (HNBs) was developed via template synthesis method followed by etching and phosphating treatments. The hierarchical morphology and composition of the Ni-Co-P HNBs were respectively characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen sorption analysis and transmission electron microscopy (TEM). High sensitivity (- 3.6 k omega / % RH), low hysteresis (- 3% RH) and good repeatability were achieved in a wide moisture range from 0% RH to 97.5% RH. By adjusting the ratio of Ni and Co, humidity sensing performance can be efficiently modulated. The optimal humidity sensing properties were attained at a ratio of Ni and Co of 1:5. Finally, the as-prepared sensor demonstrates great capability in respiratory analysis and noncontact human-machine interfacing. This work opens up a new paradigm for developing high-performance wearable sensing devices.

Automated summary

This work presents a new metal phosphide nanomaterial for energy storage and catalysis, replacing chemical sensors. The material exhibits high sensitivity, low hysteresis, and good repeatability in a wide range of humidity. By adjusting the composition, the humidity sensing performance can be efficiently modulated, showing great potential in respiratory analysis and non-contact human-machine interfacing. This research opens up new possibilities for developing high-performance wearable sensing devices.