(99.9%), formic acid (98%), glycolic acid (98%), methanol (99.5%),
and xylose (99.9%) were purchased from Sinopharm Chemical Reagent
Co., Ltd. Sodium hydroxide (96%), acetic acid (99.5%), and lactic
acid (85%) were obtained from Shanghai Lingfeng Chemical Reagent Co.,
Ltd. Gluconic acid (49–53 wt % in water) was purchased from
Sun Chemical Technology (Shanghai) Co., Ltd. Sorbitol (98%) was purchased
from Innochem (Beijing) Technology Co., Ltd. Glycolaldehyde dimer
was offered by Aladdin Reagent Company. Sodium oxalate (99.8%) and
pyruvaldehyde (40% w/w aq. solution) were purchased from Shanghai
Titan Scientific Co., Ltd. Glyceraldehyde (85%) was obtained from
Bide Pharmatech Ltd. 1,3-Dihydroxyacetone (98%) was provided by J&K
Scientific Ltd. Ag2O (99.7%, Macklin Biochemical Co., Ltd.)
was chosen as the model compound of Ag(I) in the basic solution because
Ag(I) ion could form AgOH and then generate Ag2O at a high
pH (pH > 11). The stoichiometric demand for complete oxidation
of
glucose to FA was defined as a 100% Ag2O supply according
to