2D Palladium Sulphate for Visible-Light-Driven Optoelectronic Reversible Gas Sensing at Room Temperature

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• 2D metal sulfides (MSs) are promising for gas sensors, but 2D noble metal sulfides are less explored due to exfoliation challenges.
• Noble metal sulfides often possess nonlayered structures, hindering their transformation into 2D materials.

Purpose of the Study:

• To synthesize 2D palladium sulphate (PdSO4) from palladium sulphide (PdS) bulk crystals.
• To investigate the optoelectronic properties of 2D PdSO4 for visible-light-driven gas sensing applications.
• To explore the potential of 2D ultrathin noble metal sulfide compounds in chemical sensing.

Main Methods:

• Liquid-phase exfoliation of palladium sulphide (PdS) bulk crystals.
• Synthesis of 2D PdSO4 nanosheets utilizing oxygen species in the exfoliation solvent.
• Characterization of 2D PdSO4 optoelectronic properties (bandgap, exciton lifetime).
• Fabrication and testing of a 2D PdSO4-based gas sensor for NO2 detection under blue light irradiation.

Main Results:

• Successfully synthesized ultrathin 2D PdSO4 planar nanosheets (≈3 nm thickness).
• 2D PdSO4 exhibits a narrow bandgap (≈1.35 eV) and long exciton lifetime, suitable for visible-light sensing.
• The sensor showed a reversible, selective, and sensitive response to ppb-level NO2, with a low detection limit (1.84 ppb) and enhanced response factor.

Conclusions:

• Demonstrated a viable method to create 2D ultrathin noble metal sulfide compounds from nonlayered structures.
• 2D PdSO4 shows significant potential for high-performance, visible-light-driven optoelectronic gas sensors.
• The findings open new avenues for exploring other 2D noble metal sulfide derivatives for advanced chemical sensing.