Bi N V bond: A hole-transfer bridge for high-efficient separation and transfer of carriers

Bi N V bond was formed between C x N y and BiVO 4 , which served as a hole-transfer bridge to prominently accelerate holes transfer driven by the interfacial electric field. The photocurrent of C x N y /BiVO 4 photoanode reached 1.5 mA/cm 2 at 0.6 V RHE . The photocurrent of C x N y /BiVO 4 photoanode remained 83.3% of the initial photocurrent after 10 h at 1.23 V RHE . • The photocurrent density of C x N y /BiVO 4 photoanode reached 1.5 mA/cm 2 at a low bias voltage of 0.6 V RHE . • The ABPE of C x N y /BiVO 4 photoanode achieved 0.97%. • The photocurrent density of CxNy/BiVO4 photoanode remained 83.3% after 10 h at 1.23 V RHE . • Bi N V bond can significantly accelerate holes transfer and change the coordination environment of metal ions. Addressing the inherent holes transport limitation of BiVO 4 photoanode is crucial to achieve efficient photoelectrochemical (PEC) water splitting. The construction of the hole-transfer bridge between co-catalysts and BiVO 4 photoanode could be an effective way to overcome sluggish hole-transfer kinetics of BiVO 4 photoanode. Herein, C x N y /BiVO 4 photoanode was prepared by coupling carbon nitride hydrogel (CNH) containing unsaturated N on the BiVO 4 photoanode during annealing. C x N y /BiVO 4 photoanode exhibited excellent PEC performance and stability. Photoelectrochemical tests proved that the coupling of C x N y accelerated holes transfer and enhanced oxygen evolution kinetics. X-ray photoelectron spectroscopy (XPS) and theoretical calculations confirmed the existence of the Bi N V bond between BiVO 4 photoanode and C x N y , which could serve as the hole-transfer bridge to significantly accelerate separation and transfer of carriers driven by the interfacial electric field. Moreover, it was found that the coupling of C x N y effectively inhibited the dissociation of metal ions through changing their coordination environment, resulting in the excellent stability of C x N y /BiVO 4 photoanode. This result provides unique insights into vital roles of the interfacial structure, which might have a significant impact on the construction of PEC devices.