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Understanding Self‐Photorechargeability of WO 3 for H 2 Generation without Light Illumination
Author(s) -
Ng Charlene,
Iwase Akihide,
Ng Yun Hau,
Amal Rose
Publication year - 2013
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.201200702
Subject(s) - intercalation (chemistry) , electrolyte , raman spectroscopy , cyclic voltammetry , faraday efficiency , alkali metal , excited state , chemistry , electron , electrode , electrochemistry , inorganic chemistry , materials science , analytical chemistry (journal) , optics , organic chemistry , atomic physics , physics , quantum mechanics
This work presents insight into the self‐photorechargeability of WO 3 , whereby the intercalation of positive alkali cations is accompanied by the simultaneous storage of photo‐excited electrons. The cyclic voltammetry studies verify the photo‐assisted intercalation and de‐intercalation of Na + and K + from the flower structured WO 3 . A storage capacity of up to 0.722 C cm −2 can be achieved in a saturated (0.68 M ) K 2 SO 4 electrolyte solution. However, the best photo recharge–discharge stability of the electrode are observed at a lower (0.1 M ) cation concentration. At high electrolyte concentrations, the intercalated cations are firmly trapped, as indicated by the structural modifications observed in Raman analysis, resulting in much less photocharging and discharging abilities in subsequent cycles. The study also shows that the stored electrons can be successfully used to generate H 2 with 100 % faradaic efficiency in the absence of light.