Photoelectrochemical charge kinetics and transfer mechanisms of organic curcumin (turmeric) photoelectrodes

This work presents a novel study on the water-splitting behavior of organic curcumin (C), based on its photoelectrochemical activity. The photodynamics and the kinetics, transfer mechanism, and generation of charges are evaluated for organic curcumin in 0.1 M NaOH electrolyte under visible irradiation. A charge-transfer resistance of 30.03 Ω and induced photocurrent density of 0.9 mA cm⁻² are achieved from curcumin nanosheets. The metal-sandwich effect on the kinetics, transfer mechanism, current generation, and potentiodynamics of organic curcumin is explored with Au/C, C/Au, and Au/C/Au photoelectrodes. The Au/C/Au photoelectrodes exhibit extraordinary enhancements in the kinetics, transfer mechanism, current generation, and potentiodynamics, owing to the surface plasmon resonance effect of Au. The Au/C/Au photoelectrode exhibits the lowest charge-transfer resistance of 8.18 Ω and the highest photocurrent density of 3.5 mAcm⁻², among the electrodes considered in this work. The obtained photocurrent density of Au/C/Au is 3.9 times higher than that of the pristine organic curcumin photoelectrode. Hence, organic curcumin can be utilized for photoelectrochemical water splitting, instead of the toxic chemicals used in the synthesis of photoelectrodes.