In situ surface alkalinized g-C3N4 toward enhancement of photocatalytic H2 evolution under visible-light irradiation. Issue 8 (18th August 2015)

• Record Type: Journal Article
• Authors: Li, Yunxiang; Xu, Hua; Ouyang, Shuxin; Lu, Da; Wang, Xin; Wang, Defa; Ye, Jinhua
• Is Part Of: Journal of materials chemistry. Volume 4:Issue 8(2016)
• Page Start: 2943
• Page End: 2950
• Publication Date: 2015-08-18
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c5ta05128b
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : An in situ surface alkalization over g-C3 N4 achieves 14-fold enhancement in photocatalytic H2 evolution. Abstract : Surface-alkalinization over g-C3 N4 was realized by an in situ synthesis approach of introducing KCl and NH4 Cl during the polymerization of melamine. The characterization of the Fourier transform-infrared spectrum, X-ray photoelectron spectrum, and electron spin resonance spectrum over the sample synthesized in the presence of KCl/NH4 Cl and other reference samples indicated that the K ions played an essential role in breaking the periodic chemical structure of g-C3 N4 and meanwhile the trace amount of H2 O in melamine could supply OH ions to graft hydroxyl groups. The NH4 Cl mainly contributed to exfoliation of layered g-C3 N4 particles and pushing negative shift of the conduction-band level based on the measurements of the BET surface area and valence-band X-ray photoelectron spectrum. An optimal sample, g–C3 N4 –KCl/0.1 g NH4 Cl (CN–KCl/0.1 g NH4 Cl), achieved a more than 14-fold enhancement in photocatalytic H2 evolution under visible-light irradiation compared with the pristine g-C3 N4 . The enhanced photocatalytic efficiency could be attributed to the fact that the surface hydroxyl groups and the more negative conduction-band level can promote the separation of photocarriers and offer a stronger potential for water reduction, respectively.