The role of the defect on the adsorption and dissociation of water on graphitic carbon nitride

TiO2/graphitic carbon nitride nanosheet composite with enhanced sensitivity to atmospheric water

“…Considering the well-known proton conduction in TiO 2 (ref. 33 and 34) and g-C 3 N 4 (or CNNS), 14,15,22,35–38 the present finding might be explained by additional charge carriers generated by water dissociation ( i.e. , protonic conduction).…”

“…33,34 For g-C 3 N 4 , water dissociates at the defect site and forms a mixed adsorption structure including a hydroxy group. 35 A single layer of CNNS is an indirect semiconductor with the calculated band gap energy of 1.15-2.72 eV. 36 Upon water adsorption, the sheet becomes buckled, and the band gap is direct with the band gap energy increasing to 1.79-3.05 eV.…”

Reductive Modification of Carbon Nitride Structure by Metals—The Influence on Structure and Photocatalytic Hydrogen Evolution

“…Similarly, it was also demonstrated that the introduction of defects in g-C 3 N 4 nanosheets could significantly enhance the photocatalytic hydrogen evolution [36,41,42]. The large role of structural defects within g-C 3 N 4 as water adsorption and dissociation sites was also confirmed by theoretical calculations [43].…”

Nonadiabatic Dynamics of Photocatalytic Water Splitting on A Polymeric Semiconductor

“…Theoretical models and computational studies offer a powerful tool to investigate the principles of photocatalytic water splitting reactions and complement the experiments. As a schematic model, adsorption of a single water molecule on g-C 3 N 4 sheet was previously explored by first-principles approaches. − The studies reported that the buckled sheet, rather than the planar g-C 3 N 4 , is more favorable for water adsorption and the most stable adsorption configuration comprises a water molecule standing on top of the intrinsic vacancy with an adsorption energy of ∼0.5 eV. However, the simple models with one to a few water molecules neglect the complex solid–liquid interactions and the intertwined structural and electronic properties of water/g-C 3 N 4 interface under real circumstances for solar-to-hydrogen production .…”

“…Different from the water adsorption on some metal oxide surfaces, , the 2D polymeric structure of g-C 3 N 4 contains intrinsic vacancies which serve as new adsorption sites and catalytic centers. There are two major adsorption forms of water molecules on the intrinsic vacancy in g-C 3 N 4 nanosheet: Λ-type and Γ-type shown in Figure a, respectively. To give a quantitative description of the adsorption configuration, the tilt angle (θ) is defined as the angle between the O-H bond of water molecule and the normal direction of g-C 3 N 4 surface, and the molecule height ( Z ) is the vertical distance of oxygen atom from the sheet.…”