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Photocatalytic Hydrogen Evolution from Silica‐Templated Polymeric Graphitic Carbon Nitride–Is the Surface Area Important?
Author(s) -
Li Xiaobo,
Masters Anthony F.,
Maschmeyer Thomas
Publication year - 2015
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201402567
Subject(s) - photocatalysis , graphitic carbon nitride , mesoporous material , materials science , delocalized electron , carbon fibers , specific surface area , catalysis , chemical engineering , hydrogen , condensation , mesoporous silica , carbon nitride , photochemistry , nitride , surface modification , nanotechnology , chemistry , organic chemistry , composite material , physics , layer (electronics) , composite number , engineering , thermodynamics
Low‐surface‐area, mesoporous silica‐templated polymeric graphitic carbon nitride (SBA–g‐C 3 N 4 ), when irradiated with visible light, exhibits a greatly improved photocatalytic hydrogen evolution rate as compared to that of conventional bulk g‐C 3 N 4 synthesized directly from the condensation of dicyandiamide. It also performs very similarly to high‐surface‐area mesoporous g‐C 3 N 4 on a per‐unit mass basis. However, on the per‐unit area basis it greatly outperforms the other materials. The intrinsically high surface activity of SBA–g‐C 3 N 4 was confirmed by using two different co‐catalysts, in situ photodeposited Pt and a structurally well‐defined molecular cobaloxime. Instead of the magnitude of the surface area as the dominant feature that determines activity, it was established that the high activity of SBA–g‐C 3 N 4 results from a much higher number of delocalized electrons present and a suppressed recombination probability of photogenerated electron–hole pairs.