inorganic chemistry

No energy

conversion

CB

VB

ΔG ( < 0)

e–

h+

Ephoton

Energy

Shorter ———— Longer

Wavelength

E ΔG ( > 0)

photon

CB

VB h

+

e–

Energy

(energy conversion efficiency)

= fΔG/Ephoton

(a)

(b)

(c)

h

e

ΔG

Δb

Ephoton

FIG. 5. (a) Photo-to-chemical energy-conversion efficiency of
photocatalytic reaction calculated as an integral of the product of
apparent quantum efficiency (f) and Gibbs-energy change (storage)
divided by photon energy (Ephoton) as a function of wavelength. (b) In
the case where Gibbs-energy change is negative, energy-conversion effi-
ciency cannot be defined, or is defined to be zero. (c) Electrochemically
biased (Db) photoelectrochemical cell consisting of an n-type semicon-
ductor and metal counter electrodes.

PHOTOCATALYSIS BY INORGANIC SOLID MATERIALS 405