Single-crystal-ordered-mesoporous metal nitrides without intrinsic Raman signals for highly sensitive SERS detection.

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Synthesis

Background:

• Synthesizing transition metal nitrides (TMNs) is challenging due to high reaction barriers, hindering tailored material design.
• Existing methods struggle with precise control over TMN structures.
• Developing novel TMNs with specific morphologies is crucial for advanced applications.

Purpose of the Study:

• To develop a novel strategy for synthesizing single-crystal ordered mesoporous (SCOM) transition metal nitrides (TMNs).
• To investigate the key factors controlling the formation of SCOM-TMNs.
• To evaluate the potential of SCOM-structured WN as a substrate for surface-enhanced Raman scattering (SERS).

Main Methods:

• A molten-salt/template strategy was employed for TMN synthesis.
• Hydroxylation of templates and formation of metal oxides were identified as critical steps.
• Five types of SCOM-TMNs (WN, MoN, TiN, VN, CoN) were successfully synthesized.

Main Results:

• The strategy enabled the precise customization of SCOM-structured TMNs.
• Hydroxylation and metal oxide formation were confirmed as key factors.
• SCOM-structured WN exhibited no intrinsic Raman signals, eliminating background interference.
• The WN substrate achieved an ultrahigh Raman enhancement factor (7.5 × 10^7) and a low detection limit (1 × 10^-12 M).

Conclusions:

• The molten-salt/template method is effective for synthesizing SCOM-TMNs.
• SCOM-structured WN presents a promising, interference-free substrate for highly sensitive SERS.
• This advancement resolves background interference issues in non-metallic SERS substrates.