Kinetic Data and Molecular Mechanism

Although not explicitly stated, water was considered to be the reduction product of dioxygen according to a dehydrogenation mechanism leading to gluconate as the oxidation product 

In the second investigation dealing with naked gold particles, the most important result was the detection of hydrogen peroxide instead of water as the reduction product of dioxygen. 

In fact during the conversion of glucose, a careful titration with permanganate allowed us to quantify H2O2 in a 1 1 ratio with respect to gluconate, as shown in Table 13.2 [21]. 

Moreover, according to kinetic experiments at low glucose concentrations ( 0.1M), a first reaction order was found, tending to an asymptote at higher concentrations (0.5 M). A first-order dependence was also found for the O2 concentration. 

An Eley-Rideal mechanism, characterised by the adsorption of glucose in its hydrated form on gold with equilibrium constant Kq, followed by reaction with oxygen coming from the Uquid phase, according to Eqs. (13.4)-(13.7), can justify the result. 

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