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Highly efficient photocatalytic H₂ evolution from water using visible light and structure-controlled graphitic carbon nitride.

Martin DJ, Qiu K, Shevlin SA, Handoko AD, Chen X, Guo Z, Tang J - Angew. Chem. Int. Ed. Engl. (2014)

Bottom Line: Herein, an effective strategy for synthesizing extremely active graphitic carbon nitride (g-C3N4) from a low-cost precursor, urea, is reported.The reaction proceeds for more than 30 h without activity loss and results in an internal quantum yield of 26.5% under visible light, which is nearly an order of magnitude higher than that observed for any other existing g-C3N4 photocatalysts.Furthermore, it was found by experimental analysis and DFT calculations that as the degree of polymerization increases and the proton concentration decreases, the hydrogen-evolution rate is significantly enhanced.

View Article: PubMed Central - PubMed

Affiliation: Solar Energy Group, Department of Chemical Engineering, UCL, Torrington Place, London, WC1E 7JE (UK).

No MeSH data available.


Hydrogen evolution with a 300 W Xe lamp, 3 wt % Pt, and TEOA as ahole scavenger: a) full arc, b) λ≥395 nm.
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fig01: Hydrogen evolution with a 300 W Xe lamp, 3 wt % Pt, and TEOA as ahole scavenger: a) full arc, b) λ≥395 nm.

Mentions: For comparison, samples of g-C3N4 were successfully prepared by usingdifferent precursors (urea, dicyandiamide (DCDA), and thiourea) under identical conditions andcharacterized by X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectroscopy, transmission electron microscopy (TEM), and UV/Vis and Raman spectroscopy(see Figures S2 and S3 in the Supporting Information for details of characterization andanalysis). Graphitic carbon nitride synthesized from different precursors (600 °C,5 °C min−1 ramp rate) was tested for hydrogen evolution in anaqueous sacrificial solution containing triethanolamine (TEOA) at room temperature and atmosphericpressure, in a procedure similar to a previously reported method.6, 7f The fully optimized results are shown inFigure 1 and further summarized in Table 1. The urea-derived g-C3N4 exhibitedsuperior hydrogen evolution in comparison to either the widely used DCDA- or thiourea-derivedg-C3N4 under both full arc and visible-light irradiation (Figure 1 a,b). The urea-derived g-C3N4evolved hydrogen at approximately20 000 μmol h−1 g−1,15 times faster than DCDA-derived and 8 times higher than thiourea-derivedg-C3N4, as reflected in the turnover number (TON, over a platinum cocatalyst;see the Supporting Information for the calculation): Urea-derived g-C3N4 had aTON of 641.1, which is much higher than that of the other samples.


Highly efficient photocatalytic H₂ evolution from water using visible light and structure-controlled graphitic carbon nitride.

Martin DJ, Qiu K, Shevlin SA, Handoko AD, Chen X, Guo Z, Tang J - Angew. Chem. Int. Ed. Engl. (2014)

Hydrogen evolution with a 300 W Xe lamp, 3 wt % Pt, and TEOA as ahole scavenger: a) full arc, b) λ≥395 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257501&req=5

fig01: Hydrogen evolution with a 300 W Xe lamp, 3 wt % Pt, and TEOA as ahole scavenger: a) full arc, b) λ≥395 nm.
Mentions: For comparison, samples of g-C3N4 were successfully prepared by usingdifferent precursors (urea, dicyandiamide (DCDA), and thiourea) under identical conditions andcharacterized by X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectroscopy, transmission electron microscopy (TEM), and UV/Vis and Raman spectroscopy(see Figures S2 and S3 in the Supporting Information for details of characterization andanalysis). Graphitic carbon nitride synthesized from different precursors (600 °C,5 °C min−1 ramp rate) was tested for hydrogen evolution in anaqueous sacrificial solution containing triethanolamine (TEOA) at room temperature and atmosphericpressure, in a procedure similar to a previously reported method.6, 7f The fully optimized results are shown inFigure 1 and further summarized in Table 1. The urea-derived g-C3N4 exhibitedsuperior hydrogen evolution in comparison to either the widely used DCDA- or thiourea-derivedg-C3N4 under both full arc and visible-light irradiation (Figure 1 a,b). The urea-derived g-C3N4evolved hydrogen at approximately20 000 μmol h−1 g−1,15 times faster than DCDA-derived and 8 times higher than thiourea-derivedg-C3N4, as reflected in the turnover number (TON, over a platinum cocatalyst;see the Supporting Information for the calculation): Urea-derived g-C3N4 had aTON of 641.1, which is much higher than that of the other samples.

Bottom Line: Herein, an effective strategy for synthesizing extremely active graphitic carbon nitride (g-C3N4) from a low-cost precursor, urea, is reported.The reaction proceeds for more than 30 h without activity loss and results in an internal quantum yield of 26.5% under visible light, which is nearly an order of magnitude higher than that observed for any other existing g-C3N4 photocatalysts.Furthermore, it was found by experimental analysis and DFT calculations that as the degree of polymerization increases and the proton concentration decreases, the hydrogen-evolution rate is significantly enhanced.

View Article: PubMed Central - PubMed

Affiliation: Solar Energy Group, Department of Chemical Engineering, UCL, Torrington Place, London, WC1E 7JE (UK).

No MeSH data available.