Iron-Doped Carbon Nitride-Type Polymers as Homogeneous Organocatalysts for Visible Light-Driven Hydrogen Evolution

Abstract

Graphitic carbon nitrides have appeared as a new type of photocatalyst for water splitting, but their broader and more practical applications are oftentimes hindered by the insolubility or difficult dispersion of the material in solvents. We herein prepared novel two-dimensional (2D) carbon nitride-type polymers doped by iron under a mild one-pot method through preorganizing formamide and citric acid precursors into supramolecular structures, which eventually polycondensed into a homogeneous organocatalyst for highly efficient visible light-driven hydrogen evolution with a rate of ∼16.2 mmol g(-1) h(-1) and a quantum efficiency of 0.8%. Laser photolysis and electrochemical impedance spectroscopic measurements suggested that iron-doping enabled strong electron coupling between the metal and the carbon nitride and formed unique electronic structures favoring electron mobilization along the 2D nanomaterial plane, which might facilitate the electron transfer process in the photocatalytic system and lead to efficient H2 evolution. In combination with electrochemical measurements, the electron transfer dynamics during water reduction were depicted, and the earth-abundant Fe-based catalyst may open a sustainable strategy for conversion of sunlight into hydrogen energy and cope with current challenging energy issues worldwide.

Boosting Visible‐Light‐Driven Photocatalytic Hydrogen Evolution with an Integrated Nickel Phosphide–Carbon Nitride System

“…[11,25] The acquired rate was 3.3 times higher than our previously published work with the Ni 0 -sg-CN catalyst [4] and the activity is 54 %ofPt-sg-CN with similar Pt loading ( Figure S12). [26,27] This result evidences that the highly expensive Pt can be replaced by the non-noble Ni 2 Pc o-catalyst with similar efficiency. Theh ighest AQEo f4 .8 %w as attained in first 1hof photocatalytic reaction and more than 1.34 %w as retained over the period of 24 h. Thev alue obtained here is far better than many other reported carbon nitride systems loaded with non-noble co-catalyst as listed in Table S2.…”

High‐Performance Photoelectrochemical Water Oxidation with Phosphorus‐Doped and Metal Phosphide Cocatalyst‐Modified g‐C3N4 Formation Through Gas Treatment

“…[13][14][15][16][17][18][19][20][21][22] In this context, metal (e.g.,C u, Fe, and Zn) [14][15][16] and nonmetal (e.g.,S ,C , Graphitic carbon nitride (g-C 3 N 4 )h as been widely exploreda sa photocatalyst for water splitting. [13][14][15][16][17][18][19][20][21][22] In this context, metal (e.g.,C u, Fe, and Zn) [14][15][16] and nonmetal (e.g.,S ,C , Graphitic carbon nitride (g-C 3 N 4 )h as been widely exploreda sa photocatalyst for water splitting.…”

Enhancing Light-Driven Production of Hydrogen Peroxide by Anchoring Au onto C3N4 Catalysts

“…The optical absorption properties of the supported catalysts were characterized by UV-visible diffuse reflectance spectra (Figure 4a). These spectra were obtained by converting the reflection data that was measured using the Kubelka-Munk equation: F(R) = (1 − R) 2 /2R, where R is the reflectance [39]. The three Au/C 3 N 4 samples showed enhanced absorption in both the UV and visible regions when compared with the bare C 3 N 4 .…”

“…The bandgap of the catalysts was also determined from the Tauc plots. The Tauc plots of Au/C 3 N 4 -500(N 2 ) and Au/C 3 N 4 -500(Air) were derived according to the equation (F(R)·hυ) 2 = A(hυ-E g ), where h was Plank constant, υ was the frequency, A was a constant, and E g was the band gap ( Figure S9) [39,46,47]. The estimated bandgap was 2.83 eV and 2.85 eV for the Au/C 3 N 4 -500(N 2 ) and Au/C 3 N 4 -500(Air), respectively.…”