Rational Design of Carbon Nitride Photoelectrodes with High Activity Toward Organic Oxidations

Abstract

Carbon nitride (CN_x ) is a light-absorber with excellent performance in photocatalytic suspension systems, but the activity of CN_x photoelectrodes has remained low. Here, cyanamide-functionalized CN_x (^NCN CN_x ) was co-deposited with ITO nanoparticles on a 1.8 Å thick alumina-coated FTO electrode. Transient absorption spectroscopy and impedance measurements support that ITO acts as a conductive binder and improves electron extraction from the ^NCN CN_x , whilst the alumina underlayer reduces recombination losses between the ITO and the FTO glass. The Al₂ O₃ |ITO : ^NCN CN_x film displays a benchmark performance for CN_x -based photoanodes with an onset of -0.4 V vs a reversible hydrogen electrode (RHE), and 1.4±0.2 mA cm^-2 at 1.23 V vs RHE during AM1.5G irradiation for the selective oxidation of 4-methylbenzyl alcohol. This assembly strategy will improve the exploration of CN_x in fundamental and applied photoelectrochemical (PEC) studies.