Photocatalytic Hydrogen Evolution from Glycerol and Water over Nickel-Hybrid Cadmium Sulfide Quantum Dots under Visible-Light Irradiation

Natural photosynthesis offers the concept of storing sunlight in chemical form as hydrogen (H2), using biomass and water. Herein we describe a robust artificial photocatalyst, nickel‐hybrid CdS quantum dots (Nih‐CdS QDs) made in situ from nickel salts and CdS QDs stabilized by 3‐mercaptopropionic acid, for visible‐light‐driven H2 evolution from glycerol and water. With visible light irradiation for 20 h, 403.2 μmol of H2 was obtained with a high H2 evolution rate of approximately 74.6 μmol h−1 mg−1 and a high turnover number of 38 405 compared to MPA‐CdS QDs (mercaptopropionic‐acid‐stabilized CdS quantum dots). Compared to CdTe QDs and CdSe QDs, the modified CdS QDs show the greatest affinity toward Ni2+ ions and the highest activity for H2 evolution. X‐ray photoelectron spectroscopy (XPS), inductively‐coupled plasma atomic emission spectrometry (ICP‐AES), and photophysical studies reveal the chemical nature of the Nih‐CdS QDs. Electron paramagnetic resonance (EPR) and terephthalate fluorescence measurements clearly demonstrate water splitting to generate ⋅OH radicals. The detection of DMPO‐H and DMPO‐C radicals adduct in EPR also indicate that ⋅H radicals and ⋅C radicals are the active species in the catalytic cycle. In good Nick: A simple and robust photocatalyst based on hybrid cadmium sulfide quantum dots with nickel complex active sites (Nih‐CdS QDs) enables the photocatalytic production of hydrogen (H2) from glycerol and water. Using the Nih‐CdS QDs allows to achieve a high rate of H2 production as well as a high turnover number over 20 h of irradiation (λ>400 nm). The performance is the highest activity known to date for H2 production from glycerol by photocatalysis.