Heterogeneous photocatalysis for air and water treatment: Fundamental needs for quantum efficiency enhancement
- North Carolina State Univ., Raleigh, NC (United States)
In the remediation industries, a useful treatment technology must be {open_quotes}general, robust, and cheap{close_quotes}. Among oxidation processes, heterogeneous photocatalysis is now broadly demonstrated to destroy common water and air contaminants. The potential process uses of highly stable titania, long lived lamps (one year), and room temperature operation, indicating a simple and robust process. We are left to address the third criterion: Can photocatalysis be {open_quotes}cheap{close_quotes}? In both liquid phase and gas phase treatment and purification by photocatalysis, it is established that the primary barrier to commercialization is often cost. Cost in return is dominated by the efficiency with which solar or lamp photons are harvested for productive light, and subsequent dark, reactions. This paper therefore defines fundamental needs in photocatalysis for pollution control in terms of activities which could lead to quantum efficiency enhancement. We first recall three related definitions. The quantum yield (QY) is the ratio of molecules of reactant converted per photon absorbed, a fundamental quantity. A less fundamental, but more easily measured variable is the quantum efficiency (QE), the ratio of molecules converted per photon entering the reactor. A third variable is the energy required per order of magnitude pollutant reduction, or EEO, a definition which provides for easy energy cost comparisons among different technologies. Each measure cited here reflects the photon, and thus the electrical, cost of this photochemistry.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- OSTI ID:
- 273402
- Report Number(s):
- NREL/CP-450-21097; CONF-9602108-; ON: DE96007867; TRN: 96:004421-0007
- Resource Relation:
- Conference: Research opportunities in photochemical sciences, Estes Park, CO (United States), 5-8 Feb 1996; Other Information: PBD: 1996; Related Information: Is Part Of Research opportunities in photochemical sciences; PB: 264 p.
- Country of Publication:
- United States
- Language:
- English
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