Enhanced selective photoelectrochemical oxidation for small organic molecules derived from molecularly imprinted single crystalline ZnO nanorods electrodes

• The single crystal (SC) molecularly imprinted ZnO nanorods was constructed.
• High selective PEC capability was achieved between two organic molecules.
• High selectivity is attributed to the excellent imprinted expression on imp-ZnO.

To solve the problem of poor selectivity on photoelectrochemical (PEC) oxidation toward small organic molecules especially has the similar chemical structures, a novel method in this work was proposed for achieving a high selective PEC oxidation by constructing molecularly imprinted sites on a single crystalline (SC) ZnO surface (imp-ZnO). Though a crystal-seed-assisted hydrothermal method, the phenol (C6H5-OH) imp-ZnO and p-hydroxybenzoic acid (PHBA, HOOC-C6H4-OH) imp-ZnO electrodes were prepared, which were in the form of vertically aligned nanorods with maintained single crystalline. The results showed the high selective PEC oxidation capabilities were obtained on SC imp-ZnO electrodes toward target between phenol and PHBA, with selective factor R of 5.64 and 2.38 respectively. This was attributed to their excellent imprinted expression with high value of imprinting factor S (1.86 and 1.55), deriving from an obvious difference of photocurrent enhancement (5.5–8 times) on SC imp-ZnO between target and nontarget. Such kind of single crystalline ZnO substrate is essential to constructed high-quality molecularly imprinted sites with clear size and hard shape for a great recognition effect.

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