Carbon Nitride Synthesis and Structure

Our research into novel molecular routes towards extended solid-state structures containing carbon with nitrogen involves a various strategies including:

· molecular synthesis and characterization of single-source precursors to CN_x solids

· thermal properties and volatility of synthesized precursors

· screening of various decomposition methods including:

thermal, photolytic, solvothermal, vapor deposition

· characterization of decomposition products and byproducts by techniques including:

IR, UV-vis, NMR, TG/DTA, electron microscopy, X-ray diffraction

· modification of product structure or properties at atomic or macroscopic levels

 

One of our initial proof-of-concept demonstrations using energetic precursors was the all carbon-nitrogen precursor, triazidotriazine, (C₃N₃)(N₃)₃ or C₃N₁₂.  This precursor melts below 100 ºC and decomposes to nitrogen-rich solids (C₃N_4+x) upon careful heating below 190 ºC.  Solid-state ¹³C NMR, IR, XPS, and bulk elemental analysis clearly show that the amorphous structures formed from the decomposition of neat C₃N₁₂ still contain significant C=N character and sp² carbon bonding.  Microscopy indicates that the C₃N_4+x surfaces contain a large number of pores (ca. 100 nm).  Related precursor routes lead to comparable network materials with nitrogen contents > 50 mol% nitrogen.  Based on our data, these “carbon nitrides” are comprised of large heterocyclic units (triazines or heptazines - C₆N₇) linked by >N-H components.

 

Several links to one-page executive summaries of recent papers are listed below.  Links to the complete papers are available on the full publications page (see left side bar).

 

Crystal structure of heptazine triazide and its conversion to carbon nitride networks

 

(C₃N₃)(N₃)₃ precursor decomposition route to C₃N₅ network materials

 

Thermal decomposition of trichloromelamine to C₃N_4+xH_y powders

 

Sublimation of carbon nitride powders to deposit thin films

 

Carbon nitride thin films from CVD of (C₃N₃)(N₃)₃

 

Triazine precursors for CVD of semiconducting nitrogen-rich and conducting nitrogen-poor graphite-like films