Photocatalytic biomass conversion
represents an ideal way of generating
syngas because of the sustainable use of biomass carbon and solar
energy. However, the lack of efficient electron–proton transfer
limits its efficiency. We here report an unprecedented method to simultaneously
increase both the electron and proton transfer by creating surface
sulfate ions on the CdS catalyst ([SO4]/CdS). Surface sulfate
ion [SO4] is bifunctional, serving as the proton acceptor
to promote proton transfer, and increasing the oxidation potential
of the valence band to enhance electron transfer. [SO4]/CdS
produces a syngas mixture from glycerol without CO2. Compared
with pristine CdS, [SO4]/CdS exhibits 9-fold higher CO
generation rate (0.31 mmol g–1 h–1) and 4-fold higher H2 generation (0.05 mmol g–1 h–1). A wide range of sugars, such as glucose,
fructose, maltose, sucrose, xylose, lactose, insulin, and starch,
were facilely converted into syngas. This study reports the pivotal
effect of surface sulfate ion on electron–proton transfer in
photocatalysis and provides a facile method for increasing photocatalytic
efficiency.