Ultrathin g-C3N4/Mo:BiVO4 photoanode for enhanced photoelectrochemical water oxidation.

A g-C 3 N 4 /Mo:BiVO 4 (CMB) heterojunction photoanode is constructed with enhanced photoelectrochemical (PEC) water oxidation performance, in which ultrathin g-C 3 N 4 is coated on Mo-doped BiVO 4. CMB shows a remarkable water oxidation photocurrent of 3.11 mA cm−2 at 1.23 V vs. RHE, which is 3.21 times higher than pristine BiVO 4. The maximal incident photon-to-current efficiency (IPCE) reaches 45.5% at 430 nm and the applied bias photo-to-current efficiency (ABPE) reaches 0.74% at 0.78 V vs. RHE, which are 2.62 and 5.76 times compared with pristine BiVO 4 , respectively. The amounts of hydrogen and oxygen generated by CMB are 18.58 and 9.32 μmol within 1 h, which are 4.66 and 5.51 times higher than pristine BiVO 4. The significant enhancements are attributed to the improvement of charge separation and acceleration of oxygen evolution reaction (OER) kinetics. Mo-dopant enhances charge separation due to its excellent electron transfer capability. Ultrathin g-C 3 N 4 also boosts charge separation via forming a heterojunction with Mo:BiVO 4 and promotes OER kinetics by accelerating the transfer of holes to the photoelectrode surface. The work testifies the promise of combing metal-doping with constructing heterojunctions using ultrathin g-C 3 N 4 to enhance water oxidation performance, and provides an excellent reference for designing and constructing efficient photoanodes for PEC water oxidation. • A new photoanode CMB was obtained by coating ultrathin g-C 3 N 4 on Mo:BiVO 4. • CMB showed higher PEC water oxidation performance than most BiVO 4 -based photoanodes. • Mo-dopant enhanced charge separation due to its electron transfer capability. • Ultrathin g-C 3 N 4 promoted charge separation and OER kinetics. • Combing metal-doping with constructing heterojunction had potential for photoanodes. [ABSTRACT FROM AUTHOR]