The g‐C₃N₄/C₂N Nanocomposite: A g‐C₃N₄‐Based Water‐Splitting Photocatalyst with Enhanced Energy Efficiency

Abstract

Water-splitting photocatalysts with good energy efficiency are highly desirable, among which metal-free graphitic carbon nitride (g-C3 N4 ) is considered to be very promising and has been intensively studied in recent years. However, its practical application is hindered by the relatively low efficiencies of visible-light absorption and electron-hole separation. Herein, based on first-principles calculations, it is predicted that, by forming nanocomposites with another carbon nitride (C2 N), the energy efficiency of g-C3 N4 can be significantly improved. On one hand, C2 N has a wide, strong optical absorption in the visible-light region, which acts as a photosensitizer and enhances the photoabsorption efficiency of the composite photocatalyst. On the other hand, C2 N forms a type II heterojunction with g-C3 N4 , which leads to efficient separation of photogenerated electron-hole pairs through the chemical potential difference between the two components. These results provide a potential route to achieve highly efficient metal-free photocatalysts for water splitting.

Coupling of Bifunctional CoMn‐Layered Double Hydroxide@Graphitic C3N4 Nanohybrids towards Efficient Photoelectrochemical Overall Water Splitting

“…The bandgap (2.7 eV) leads to low absorption of the solars pectrum above l = 460 nm. [45][46][47][48] To solve these issues, great efforts have been made to boost the catalytic activityo fg -C 3 N 4 ,s uch as doping with metal elements, combinationw ith other semiconductors, and/or copolymerizationt oe xtend the absorption range. [47][48][49][50] In this regard, the combination of g-C 3 N 4 with LDH semiconductorsc ould be an impressive strategy for improving the photo-/electrocatalytical properties because the similar2 Dl ayered structure is beneficial for full electronic coupling, charge separation, and electron transfer.F urthermore, the chemical composition and morphology of LDHs can be finely modified, which favors improvements in electrical conductivity and charge-separation efficiency.F rom an elemental view,i ti s known that Co 2 + and Co 3 + are active sites for electrochemical water splitting.…”

Enhanced Photocatalytic Water Splitting in a C2N Monolayer by C‐Site Isoelectronic Substitution

“…theoretically predicted that the band gap and band edge positions of C 2 N can be tuned by varying their stacking order, layer number, and external electric field for the spontaneous water splitting under visible light. Heterostructured g‐C 3 N 4 /C 2 N and C 2 N/graphene photocatalyst showed an enhanced efficiency because of the efficient separation of photogenerated electron–hole pairs and favorable band edge positions for water splitting. From computational studies, Guan et al .…”

2D CdO‐Based Heterostructure as a Promising Visible Light Water‐Splitting Photocatalyst

“…Many g‐C 3 N 4 ‐based heterostructures including g‐C 3 N 4 /g‐C 6 N 6 , g‐C 3 N 4 /CN 2 , CdS/g‐C 3 N 4 , SnS 2 /g‐C 3 N 4 , ZnO/g‐C 3 N 4 , WO 3 /g‐C 3 N 4 , C 3 N 4 /g‐C 3 N 4 , InSe/g‐C 3 N 4 , g‐C 3 N 4 /Bi 2 MoO 6 , g‐C 3 N 4 /Bi 2 WO 6 , and CuO/g‐C 3 N 4 are reported to show improved photocatalytic efficiency in contrast with pristine g‐C 3 N 4 . To obtain a higher photocatalytic efficiency, designing novel structures is still on going.…”