title: Hydrogen from Water over Openly-Structured Graphitic Carbon Nitride Polymer through Photocatalysis.
abstract: Openly-structured g-C3 N4 microspheres (CNMS) are developed through a well-controlled strategy. These materials have unique features of open 3 D structure, ordered hierarchical porosity, and improved optical and electronic properties. Hydrogen evolution from water is performed under a 300 W Xe lamp with a cut-off filter (λ>420 nm) and Pt nanoparticles are used as the co-catalyst (3.0 wt%). The catalyst prepared at 600 °C (CNMS-600) has a hydrogen evolution rate (HER) of 392 μmol h(-1) (apparent quantum yield, AQY=6.3%) at 420 nm. This value is higher than that of g-C3 N4 nanosheets prepared through thermal oxidation, liquid exfoliation, or chemical exfoliation. The HER value is only 27 μmol h(-1) (AQY=0.43%) at 420 nm for bulk g-C3 N4 from melamine. The evolution of openly-structured CNMS was investigated by TEM, FTIR, and XRD. The improved optical and electronic properties were demonstrated through UV/Vis absorption spectra, valence-band X-ray photoelectron spectroscopy, photoluminescence spectroscopy, electron paramagnetic resonance spectroscopy, and electrochemical impedance spectroscopy.
authors.affiliation: Beijing National Laboratory of Molecular Science, Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing, P.R. China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Beijing National Laboratory of Molecular Science, Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing, P.R. China. lifb@iccas.ac.cn.
authors.forename: Fengbo
authors.identifier: http://orcid.org/0000-0002-1660-7830
authors.initials: F
authors.lastname: Li
authors.affiliation: Beijing National Laboratory of Molecular Science, Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing, P.R. China.
authors.forename: Bingfeng
authors.initials: B
authors.lastname: Chen
authors.affiliation: Beijing National Laboratory of Molecular Science, Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing, P.R. China. yuangq@iccas.ac.cn.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Yuan
mesh_terms: D002384:Catalysis; D006108:Graphite / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D009570:Nitriles / Q000737:chemistry*; D055668:Photochemical Processes; D056951:Photoelectron Spectroscopy; D011108:Polymers / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014867:Water / Q000737:chemistry*
chemical_list: D009570:Nitriles; D011108:Polymers; D014867:Water; C011206:cyanogen; D006108:Graphite; D006859:Hydrogen
keywords: hydrogen; nanostructures; nitrides; photocatalysis; water splitting