Reaction Mechanism for the Photocatalytic Conversion of CO

As mentioned previously, it was found that ZrO, MgO, and Ga Oj exhibit photocatalytic activity for the conversion of CO to CO in the presence of H. However, the mechanism of the photocatalytic reaction over Ga Oj is different from those over ZrOj and MgO. For ZrO and MgO, the photocatalytic conversion of CO in the presence of proceeds on the basis of a typical Eley-Rideal mechanism, whereas the Langmuir-Hinshelwood mechanism is operative with Gafi.  

FIGURE 12.4 Dependences of the amount of CO evolved by the photoreaction (open squares) and by heat treatment after photoreaction (closed circles) on the initial amount of introduced CO. The amount of CO evolved by the heat treatment reflects the amount of surface formate. Reprinted with permission from Ref. [12]. RSC. 

FIGURE 12.5 Chemisorption isotherm of COj on Ga O (circles) and the relationship between the initial pressure of introduced CO gas and the amount of CO gas evolved over Ga O (squares). Hji ISOpmol, photoirradiation time 5h. Reprinted with permission from Ref. [15], 

FIGURE 12.6 Adsorption isotherm of Hj on Ga O after pretreatment. Reprinted with permission from Ref. [15]. American Chemical Society. 

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