ether (AR grade) were purchased from Finar Chemicals Ltd. India. CoCl2·2H2O was purchased from Sigma-Aldrich, and
were recorded using an Ocean Insight USB2000+XR1-ES spectrophotometer,
with the DT-MINI-2-GS light source using 1 cm path length in a 1 mL
Kozima-made quartz cuvette. The ATR-FTIR spectra of pure solid samples
were recorded on a PerkinElmer spectrometer. The atmosphere with different
oxygen concentrations was created by a calibrated Mettler Toledo M800
Transmitter with an InPro 6000 Optical Sensor. The pH values of the
aqueous solution were measured in a benchtop ORION STAR A111 pH Meter
(Thermo Scientific).