Dependency‐oriented arguments have not focused sufficient attention on the growing international debt crisis. This omission is unfortunate because foreign debt has introduced several important dynamics into the world capitalist system. Perhaps most important, the International Monetary Fund (IMF) has emerged as one of the most powerful transnational financial institutions, as it makes loans to and evaluates credit worthiness of Third World states. To be acceptable credit risks, underdeveloped states often must implement a number of IMF “structural adjustment” or austerity measures. Our cross‐national analysis‐which includes an examination of important outliers‐indicates that IMF‐imposed conditionality is the primary impediment to economic expansion in the Third World. Growing service payments on the external debt also inhibit economic growth, but less so. Moreover, although structural adjustment does not yet significantly impact physical quality of life, foreign investment and level of international reserves do exhibit a negative effect on this indicator. Dependency arguments should be revised and broadened given the profound impact of the global debt crisis.
Ferroelectric materials hold great promise in the field
of photocatalytic
water splitting due to their spontaneous polarization that sets up
an inherent internal field for the spatial separation of photogenerated
charges. The ferroelectric polarization, however, is generally accompanied
by some intrinsic defects, particularly oxygen vacancies, whose impact
upon photocatalysis is far from being fully understood and modulated.
Here, we have studied the role of oxygen vacancies over the photocatalytic
behavior of single-domain PbTiO3 through a combination
of theoretical and experimental viewpoints. Our results indicate that
the oxygen vacancies in the negatively polarized facet (001) are active
sites for water oxidation into O2, while the defect-free
sites prefer H2O2 as the oxidation product.
The apparent quantum yield at 435 nm for photocatalytic overall water
splitting with PbTiO3/Rh/Cr2O3 is
determined to be 0.025%, which is remarkable for single undoped metal
oxide-based photocatalysts. Furthermore, the strong correlation among
oxygen vacancies, polarization strength, and photocatalytic activity
is properly reflected by charge separation conditions in the single-domain
PbTiO3. This work clarifies the crucial role of oxygen
vacancies during photocatalytic reactions of PbTiO3, which
provides a useful guide to the design of efficient ferroelectric photocatalysts
and their water redox reaction pathways.
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