Porous graphitic carbon nitride synthesized via direct polymerization of urea for efficient sunlight-driven photocatalytic hydrogen production

Abstract

Energy captured directly from sunlight provides an attractive approach towards fulfilling the need for green energy resources on the terawatt scale with minimal environmental impact. Collecting and storing solar energy into fuel through photocatalyzed water splitting to generate hydrogen in a cost-effective way is desirable. To achieve this goal, low cost and environmentally benign urea was used to synthesize the metal-free photocatalyst graphitic carbon nitride (g-C₃N₄). A porous structure is achieved via one-step polymerization of the single precursor. The porous structure with increased BET surface area and pore volume shows a much higher hydrogen production rate under simulated sunlight irradiation than thiourea-derived and dicyanamide-derived g-C₃N₄. The presence of an oxygen atom is presumed to play a key role in adjusting the textural properties. Further improvement of the photocatalytic function can be expected with after-treatment due to its rich chemistry in functionalization.

Trends and challenges for microporous polymers

“…Porous polymeric carbon nitrides have been prepared, which indeed showed largely enhanced photocatalytic activity. [137][138][139] Porosity in these materials mainly by hard templating, i.e. replication of nanostructures of silica for example.…”

Graphitic g-C3N4-WO3Composite: Synthesis and Photocatalytic Properties

“…For WM-500, the most intense peak at 398.7 eV is assigned to sp 2 hybridized aromatic nitrogen atoms bonded to carbon atoms (C-N=C). 43 The weak peak at 400.3 eV for WM-600 and WM-700 samples may come from W-N bond in the Ndoped WO 3 . 44 The XPS of the three samples in the O 1s binding energy regions were shown in Figure 5(c).…”

Fluorescein supramolecular nanosheets: A novel organic photocatalyst for visible-light-driven H2 evolution from water

“…The supramolecular NSs exhibit higher activity (Fig. 4a) than PCN synthesized from urea at 550°C according to Chen's report [39], and the corresponding apparent quantum efficiency (QE) of supramolecular NS at 420 ± 10 nm reaches 1.2%. However, it is much lower than the stateof-art results from PCN [40][41][42].…”