TY - JOUR
T1 - Efficient visible and NIR light-driven photocatalytic CO2 reduction over defect-engineered ZnO/carbon dot hybrid and mechanistic insights
AU - Lin, Liang-Yi
AU - Liu, Chieh
AU - Hsieh, Tsung Ta
N1 - Funding Information:
The authors gratefully acknowledge the financial support from the Ministry of Science and Technology of Taiwan through grant No.: MOST 108-2218-E-009-065-MY3 .
PY - 2020/11
Y1 - 2020/11
N2 - Photocatalytic CO2 reduction with H2O over wide bandgap semiconductor-based photocatalysts is significantly limited by the low light utilization efficiency and poor activation of CO2/H2O molecules on the photocatalyst's surface. Herein, we demonstrate that oxygen-deficient ZnO/carbon dot (OD-ZnO/C) hybrid, rationally engineered with synergistically enhanced CO2/H2O activation ability and increased light utilization efficiency, showed excellent full spectrum (UV, visible and NIR light)-driven CO2 photoreduction. Under UV–Vis-NIR, Vis-NIR and NIR light separately, the optimized sample demonstrated high quantum yields of 0.26%, 0.13% and 0.05% for CO production, yields which are considerably superior to the reported values in the literature. The synergistic effects between OD-ZnO and carbon dots for visible- and NIR-driven CO2 reduction were systematically investigated. Experimental results showed that both the defect-induced sub-band in OD-ZnO and the upconverting emission from the carbon dots effectively increased the light utilization efficiency within the UV–Vis to NIR region, and the heterojunctions formed between OD-ZnO and carbon dots promoted the efficient separation of charge carriers. Meanwhile, the defect-rich surface ensures the efficient adsorption and activation of CO2/H2O into the key intermediate CO2–, formate, and hydroxyl species, which are effectively converted under light illumination from UV–Vis to NIR region. Based on the combined results of the CO2 photoreduction analysis and the material characterization, plausible CO2 photoreduction pathways under visible and NIR light irradiation are proposed.
AB - Photocatalytic CO2 reduction with H2O over wide bandgap semiconductor-based photocatalysts is significantly limited by the low light utilization efficiency and poor activation of CO2/H2O molecules on the photocatalyst's surface. Herein, we demonstrate that oxygen-deficient ZnO/carbon dot (OD-ZnO/C) hybrid, rationally engineered with synergistically enhanced CO2/H2O activation ability and increased light utilization efficiency, showed excellent full spectrum (UV, visible and NIR light)-driven CO2 photoreduction. Under UV–Vis-NIR, Vis-NIR and NIR light separately, the optimized sample demonstrated high quantum yields of 0.26%, 0.13% and 0.05% for CO production, yields which are considerably superior to the reported values in the literature. The synergistic effects between OD-ZnO and carbon dots for visible- and NIR-driven CO2 reduction were systematically investigated. Experimental results showed that both the defect-induced sub-band in OD-ZnO and the upconverting emission from the carbon dots effectively increased the light utilization efficiency within the UV–Vis to NIR region, and the heterojunctions formed between OD-ZnO and carbon dots promoted the efficient separation of charge carriers. Meanwhile, the defect-rich surface ensures the efficient adsorption and activation of CO2/H2O into the key intermediate CO2–, formate, and hydroxyl species, which are effectively converted under light illumination from UV–Vis to NIR region. Based on the combined results of the CO2 photoreduction analysis and the material characterization, plausible CO2 photoreduction pathways under visible and NIR light irradiation are proposed.
KW - Carbon dot
KW - CO reduction
KW - Full solar spectrum photocatalysis
KW - Oxygen defect
KW - ZnO
UR - http://www.scopus.com/inward/record.url?scp=85091223351&partnerID=8YFLogxK
U2 - 10.1016/j.jcat.2020.08.036
DO - 10.1016/j.jcat.2020.08.036
M3 - Article
AN - SCOPUS:85091223351
SN - 0021-9517
VL - 391
SP - 298
EP - 311
JO - Journal of Catalysis
JF - Journal of Catalysis
ER -