Graphitic Carbon Nitride Materials for Energy Applications

Abstract

Polymeric layered carbon nitrides were investigated for use as catalyst support materials for proton exchange membrane fuel cells (PEMFCs) and water electrolyzers (PEMWEs). Three different carbon nitride materials were prepared: a heptazine-based graphitic carbon nitride material (gCNM), poly (triazine) imide carbon nitride intercalated with LiCl component (PTI-Li+Cl-) and boron-doped graphitic carbon nitride (B-gCNM). Following accelerated corrosion testing, all graphitic carbon nitride materials were found to be more electrochemically stable compared to conventional carbon black (Vulcan XC-72R) with B-gCNM support showing the best stability. For the supported Pt, Pt/PTI-Li+Cl- exhibited the best durability with only 19% electrochemical surface area (ECSA) loss versus 36% for Pt/Vulcan. Superior methanol oxidation activity was observed for all gCNM supported Pt catalysts on the basis of the catalyst ECSA. Preliminary results on IrO2 supported on gCNM using a PEMWE cell revealed an enhancement in the charge-transfer resistance as the current density increases when compared to unsupported IrO2. This may be attributed to a higher active surface area of the catalyst nanoparticles on the gCNM support