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3 D Co 3 (PO 4 ) 2 –Reduced Graphene Oxide Flowers for Photocatalytic Water Splitting: A Type II Staggered Heterojunction System
Author(s) -
Samal Alaka,
Swain Smrutirekha,
Satpati Biswarup,
Das Dipti Prakasini,
Mishra Barada Kanta
Publication year - 2016
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201601214
Subject(s) - photocatalysis , graphene , heterojunction , water splitting , materials science , oxide , photoluminescence , visible spectrum , band gap , photochemistry , catalysis , hydrogen production , chemical engineering , nanotechnology , chemistry , optoelectronics , biochemistry , engineering , metallurgy
The design, synthesis, and photoelectrochemical characterization of Co 3 (PO 4 ) 2 , a hydrogen evolving catalyst modified with reduced graphene oxide (RGO), is reported. The 3 D flowerlike Co 3 (PO 4 ) 2 heterojunction system, consisting of 3 D flowerlike Co 3 (PO 4 ) 2 and RGO sheets, was synthesized by a one‐pot in situ photoassisted method under visible‐light irradiation, which was achieved without the addition of surfactant or a structure‐directing reagent. For the first time, Co 3 (PO 4 ) 2 is demonstrated to act as a hydrogen evolving catalyst rather than being used as an oxygen evolving photoanode. In particular, 3 D flowerlike Co 3 (PO 4 ) 2 anchored to RGO nanosheets is shown to possess dramatically improved photocatalytic activity. This enhanced photoactivity is mainly due to the staggered type II heterojunction system, in which photoinduced electrons from 3 D flowerlike Co 3 (PO 4 ) 2 transfer to the RGO sheets and result in decreased charge recombination, as evidenced by photoluminescence spectroscopy. The band gap of Co 3 (PO 4 ) 2 was calculated to be 2.35 eV by the Kubelka–Munk method. Again, the Co 3 (PO 4 ) 2 semiconductor displays n‐type behavior, as observed from Mott–Schottky measurements. These RGO–Co 3 (PO 4 ) 2 conjugates are active in the visible range of solar light for water splitting and textile dye degradation, and can be used towards the development of greener and cheaper photocatalysts by exploiting solar light.