Constructing boron-doped graphitic carbon nitride with 2D/1D porous hierarchical architecture and efficient N2 photofixation

Abstract

Rational design of cheap and easily available semiconductor photocatalysts for photocatalytic nitrogen fixation has attracted widespread attention. However, the enhancing efficiency of fixation nitrogen into ammonia (NH3) under mild conditions is still a challenge. Based on the energy band engineering theory, the band gap of graphitic carbon nitride (g-C3N4) can be adjusted by boron element doping. In this study, boron-doped graphitic carbon nitride with a porous rod-like 2D/1D hierarchical architecture was prepared (BCN) via a convenient hydrothermal and thermal polymerization method. Due to its special structure, the as-prepared BCN photocatalysts had a high specific surface area, enhanced visible light absorption and good photogenerated carrier separation efficiency. The optimal ammonia yield of BCN can reach 434.74 μmol·g−1·h−1 without the presence of a sacrificial agent, which was 57.35 times higher than that of bulk g-C3N4. According to the analysis of the experimental results, the excellent photocatalytic nitrogen fixation performance was due to the synergistic effect between the doping of nonmetallic boron element and the 2D/1D porous structure, which exposed more active sites, thus boosting the photocatalytic nitrogen fixation efficiency. This study provides a guiding significance for the construction of high-efficiency photocatalysts with a special 2D/1D porous hierarchical architecture in photocatalytic nitrogen fixation.