Single boron atom anchored on graphitic carbon nitride nanosheet (B/g-C2N) as a photocatalyst for nitrogen fixation:A first-principles study

It is essential to explore high efficient catalysts for nitrogen reduction in ammonia production. Based on the firstprinciples calculation, we find that B/g-C2N can serve as high performance photocatalyst in N2fixation, where single boron atom is anchored on the g-C2N to form B/g-C2N. With the introduction of B atom to g-C2N, the energy gap reduces from 2.45 e V to 1.21 e V and shows strong absorption in the visible light region. In addition, N2can be efficiently reduced on B/g-C2N through the enzymatic mechanism with low onset potential of 0.07 V and rate-determining barrier of 0.50 e V.The "acceptance-donation" interaction between B/g-C2N and N2plays a key role to active N2, and the BN2moiety of B/gC2N acts as active and transportation center. The activity originates from the strong interaction between 1π 1π*orbitals of N2and molecular orbitals of B/g-C2N, the ionization of 1π orbital and the filling of 1π*orbital can increase the N≡N bond length greatly, making the activation of N2. Overall, this work demonstrates that B/g-C2N is a promising photocatalyst for N2fixation.