PMID- 38168951
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20240327
IS  - 1463-9084 (Electronic)
IS  - 1463-9076 (Linking)
VI  - 26
IP  - 13
DP  - 2024 Mar 27
TI  - Nanoscale insights into graphene oxide reduction by tip-enhanced Raman 
      spectroscopy.
PG  - 9871-9879
LID - 10.1039/d3cp04711c [doi]
AB  - Graphene oxide (GO) has attracted substantial interest for its tunable properties 
      and as a possible intermediate for the bulk manufacture of graphene. GO and its 
      reduced derivatives display electronic and optical properties that depend 
      strongly on their chemical structure, and with proper functionalization, GO can 
      have a desirable bandgap for semiconductor applications. However, its chemical 
      activity leads to a series of unclear chemical changes under ambient conditions, 
      resulting in changes in color and solubility upon exposure to light. In this 
      paper, we study the properties of fresh and spontaneously reduced GO under 
      ambient conditions using tip-enhanced Raman spectroscopy (TERS) to map its 
      nanometer scale chemical and structural heterogeneity. We observe different types 
      of defect sites on reduced GO (rGO) by spatially mapping the D to G band peak 
      ratio and D and G band spectral positions. The higher spatial resolution and 
      out-of-plane polarization compared to conventional micro-Raman spectroscopy 
      enables us to resolve unusual features, including D-band shifting on rGO. Based 
      on statistical analysis of the spatial variations in modes and theoretical 
      calculations for different functional groups, we conclude the reduction mechanism 
      of GO is a self-photocatalytic reduction with the participation of water and 
      visible light, in which the rate determining step is electron transport through 
      the metal substrate and ion diffusion on the GO surface. These results 
      demonstrate that TERS can reveal structural and chemical details elucidating 
      reduction mechanisms, through the examination of samples at different time 
      points.
FAU - You, Xiao
AU  - You X
AUID- ORCID: 0000-0002-0357-0311
AD  - Department of Applied Physical Science, University of North Carolina at Chapel 
      Hill, Chapel Hill, USA. youxiao@westlake.edu.cn.
FAU - Maharjan, Sangita
AU  - Maharjan S
AD  - Department of Chemistry, North Carolina Central University, Durham, USA.
FAU - Vinodgopal, Kizhanipuram
AU  - Vinodgopal K
AUID- ORCID: 0000-0002-0741-6282
AD  - Department of Chemistry, North Carolina Central University, Durham, USA.
FAU - Atkin, Joanna M
AU  - Atkin JM
AUID- ORCID: 0000-0002-1211-5193
AD  - Department of Chemistry, University of North Carolina at Chapel Hill, Chapel 
      Hill, USA. jatkin@email.unc.edu.
LA  - eng
PT  - Journal Article
DEP - 20240327
PL  - England
TA  - Phys Chem Chem Phys
JT  - Physical chemistry chemical physics : PCCP
JID - 100888160
SB  - IM
EDAT- 2024/01/04 01:18
MHDA- 2024/01/04 01:19
CRDT- 2024/01/03 11:08
PHST- 2024/01/04 01:19 [medline]
PHST- 2024/01/04 01:18 [pubmed]
PHST- 2024/01/03 11:08 [entrez]
AID - 10.1039/d3cp04711c [doi]
PST - epublish
SO  - Phys Chem Chem Phys. 2024 Mar 27;26(13):9871-9879. doi: 10.1039/d3cp04711c.