Photocatalytic Reaction NO+CO $\overset{h\nu}\to$ (CO$_2$)$_{\mathrm{ads}}$+1/2N$_2$, activated on ZnO/ZnO$_{1-x}$/O$^-$ under exciton resonance excitation

The exciton channel of ZnO photoactivation was used for the first time to carry out the environmentally important photocatalytic reaction NO+CO $\overset{h\nu}\to$ (CO$_2$)$_{\mathrm{ads}}$+1/2N$_2$ $\uparrow$ on ZnO. When the excitation energy is delivered to the surface by an electrically neutral exciton, there are no losses in recombination and in overcoming the potential surface barrier, which are the main losses in the transfer of photo-generated $e^-/h^+$ pairs. To suppress the undesirable radiative decay of an exciton, the ZnO/ZnO$_{1-x}$/O$^-$ 2D structure was created on the ZnO surface, in which the exciton decays nonradiatively into a pair of long-lived local states of an electron and a hole, on which the reactionary acts occur. For the redox reaction (1), the obtained values of the quantum yield $Y$ (the number of reaction acts per one absorbed quantum) and the efficiency $E$ (the number of acts per one incident quantum) upon exciton excitation at $\lambda$ = 382 nm are 5–7 times greater than when excited in the interband absorption region at $\lambda$ = 365 nm. The methods of mass-spectrometry (MS) and thermodesorption spectroscopy (TDS) were used to study the initial, intermediate and final products of reaction (1) in the gas and adsorbed phases, and the features of the influence of the initial products NO and CO on each other during the interaction of their mixture with ZnO in the dark and under irradiation at $\lambda$ = 382 nm.