Erbium lanthanum titanate glasses were prepared by levitation melting for the spectroscopic study of ways to promote the mid-infrared fluorescence. Two series of heavily erbium doped glasses (15 wt%) were prepared with the addition of either Pr3+or Nd3+in amounts relative to Er3+of 0.05, 0.1, and 0.2. Both ions quench the lower Er3+laser level with the Pr3+doing so more rapidly. Although high co-dopant concentrations result in higher energy transfer, as clearly evidenced in upconversion and downconversion fluorescence measurements, the mid-infrared lifetime also suffers a reduction and, therefore, a balance must be struck in the co-dopant concentration. Lifetime and spectral measurements indicate that, at a fixed relative co-dopant amount, Pr3+is more effective than Nd3+at removing the bottleneck of the Er3+ 4
In this study, Mg2+‐doped mesoporous TiO2photocatalysts derived from Mg2+adsorption (MA) process on MIL‐125, a metal‐organic framework material, were prepared and employed for photocatalytic reduction of CO2to produce CO. The Mg2+doping concentration was controlled by varying the Mg2+concentration in the Mg2+adsorption process. It was demonstrated that the Mg2+doping promoted the generation of surface Ti3+and significantly increased transient photocurrent density. Over a 4 h UV/Vis irradiation period, the best performing photocatalyst, 1MA, delivered a CO production rate ∼20 times higher than that of P25, a commercially available TiO2nanopowder. It is believed that the Mg2+adsorption process introduced more favorable properties to the TiO2photocatalysts, such as higher surface area and porosity for more reactive sites, and concentrated surface Ti3+centers for improved charge transfer.
more » « less- NSF-PAR ID:
- 10239038
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemPhotoChem
- Volume:
- 5
- Issue:
- 1
- ISSN:
- 2367-0932
- Page Range / eLocation ID:
- p. 79-89
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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