Considering the rate of NH3 production, we observe a different trend compared to H2 production, Figure . Initially, the presence of g-C3N4 alone is sufficient to generate few amounts of NH3. Considering the band alignment, electrons should jump from the Cs2AgBiCl6 to the g-C3N4. As potential active sites, we calculate the formation of nitrogen vacancy in g-C3N4, resulting in VN 0 formation energies of 3.36 eV, see with previous studies. The nitrogen vacancy introduces localized energy levels within the band gap, see Figure , and introduces a (0/-) transition at 1.56 eV, see Table . Importantly, the (0/-) level of nitrogen vacancies are close to the redox potential for N2/NH3 (reported by dashed line), suggesting a plausible way for the initial steps in the photofixation mechanism.