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

ABSTRACT: The major challenge of photocatalytic water splitting, the prototypical reaction for the direct production of hydrogen by using solar energy, is to develop low-cost yet highly efficient and stable semiconductor photocatalysts. Herein, an effective strategy for synthesizing extremely active graphitic carbon nitride (g-C3N4) from a low-cost precursor, urea, is reported. The g-C3N4 exhibits an extraordinary hydrogen-evolution rate (ca. 20,000??mol?h(-1) g(-1) under full arc), which leads to a high turnover number (TON) of over 641 after 6?h. 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.

SUBMITTER: Martin DJ 

PROVIDER: S-EPMC4257501 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature