Amorphous Carbon Nitride with Three Coordinate Nitrogen (N3_C) Vacancies for Exceptional NO<i>_x</i> Abatement in Visible Light

Abstract

Abstract Over the past several decades, much effort has been applied to atmospheric nitrogen oxide (NO x ) abatement. The current techniques require high energy consumption and result in secondary pollution. Particularly, the removal of low dose ( &lt; 200 ppm) of NO x has been very challenging. Though graphitic carbon nitride (g‐CN), an eco‐friendly and sustainable material was tried as a promising metal‐free photocatalyst for NO x abatement. Herein, a one‐step, energy efficient calcination approach is developed to prepare amorphous carbon nitride (ACN) with N3 C ‐site vacancies. The visible‐light responsive range is expanded and the activation barrier of NO triple bonds is sharply decreased by one order of magnitude; 0.19 eV when compared to the 2.22 eV of g‐CN. These modifications allow the NO x removal efficiency of ACN to reach 57.1% which is among the highest in visible light. The unique N3 C ‐site vacancies are well maintained after photocatalytic NO oxidation, which shows an exceptional structural stability. This boosts the generation of singlet oxygen ( 1 O 2 ) and superoxide radical ( • O 2 − ) for complete NO removal. This study sheds light on the active site design and photocatalytic performance enhancement of g‐CN based materials by vacancy engineering.