Phase-Selective Precrystallization Enables the Topological Conversion of Uniform Mesoporous Titanium Nitride

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Nonoxide ceramics possess desirable properties but integrating mesoporosity is challenging due to high-temperature processing.
• Conventional methods disrupt mesoscopic order via lattice reconstruction and grain coarsening.

Purpose of the Study:

• To develop a novel strategy for synthesizing mesoporous nonoxide ceramics with preserved mesostructure.
• To enable topology-preserving oxide-to-nitride conversion at reduced temperatures.

Main Methods:

• Phase-selective precrystallization of mesostructured rutile TiO2 intermediates.
• Utilizing a transient carbon scaffold to suppress grain coarsening.
• Low-temperature nitridation at 700 °C.

Main Results:

• Successfully synthesized mesoporous titanium nitride (TiN) microspheres with preserved mesoscale topology.
• Achieved high surface area (82 m2 g-1), controlled pore size (17.5 nm), and minimal volume contraction (7.3%).
• Demonstrated superior performance as Ir catalyst supports for proton-exchange membrane water electrolysis (1.64 V at 1.0 A cm-2, >500 h durability at low Ir loading).

Conclusions:

• Phase-selective precrystallization is a viable strategy for creating high-performance mesoporous nonoxide ceramics.
• The developed TiN material offers enhanced catalytic activity and stability for electrochemical applications.
• This approach reconciles mesoporosity and crystallinity in nonoxide materials.