Templated synthesis of 3D hierarchical porous Co3O4 materials and their NH3 sensor at room temperature

• The 3D structure contains interconnecting macropores and mesopores for gas absorption.
• The novel structure contains lots of irregular structure defects with active sites.
• The Co3O4 presents excellent sensing performance to NH3 at room temperature.

In this paper, 3D hierarchical porous Co3O4 materials (HPCo) were synthesized via a PS spheres templated transformation route. This novel 3D structure contained not only plenty of interconnecting macropores and mesopores, but also a large amount of irregular structure defects. The Co-4 synthesized by 0.4 M Co(NO3)2·6H2O concentrations solution had the largest specific surface area of 58.75 m2 g−1 and a average particle size of 20 nm. The optimized sample presents excellent sensing performance to NH3 gas at room temperature (RT = 21 °C) with the highest sensitivity (146% to 100 ppm), fast response time (2 s to 100 ppm), and a low detection limit of 0.5 ppm. Such superior properties were attributed to the unique hierarchical porous structure, large specific surface area, excellent chemisorbed ability to oxygen species and good catalytic activity of Co3O4 nanomaterials.

3D hierarchical porous Co3O4 materials are synthesized via a PS spheres templated transformation route. This 3D structure contains not only plenty of interconnecting macropores and mesopores, but also a large amount of irregular structure defects. The materials present excellent sensing performance to NH3 gas at room temperature with the high sensitivity (146% to 100 ppm), fast response time (2 s to 100 ppm), and a low detection limit of 0.5 ppm, which are attributed to the unique hierarchical porous structure, large specific surface area, excellent chemisorbed ability to oxygen species and good catalytic activity of Co3O4.Figure optionsDownload as PowerPoint slide