The photoelectrochemical (PEC) water splitting efficiency is profoundly restricted by the limited light harvesting, rapid charge recombination, and sluggish water oxidation kinetics, in which the construction of a photoelectrode requires a strategic approach to overcome such intrinsic hurdles. Herein, we demonstrate novel black phosphorus quantum dots (BPQDs) with significant light absorbability up to the near-infrared region (NIR) to sensitize the etched BiVO4 photoanode (E-BiVO4) for a two-photon absorption tandem photoanode. A subsequent TiO2 overlayer (OL) significantly improves the stability of the E-BiVO4/BPQDs and eliminates the surface trap state to enhance charge separation. Finally, an oxygen evolution catalyst (OEC), NiOOH, loaded on E-BiVO4/BPQDs/OL further improves the water oxidation kinetics. The rationally designed E-BiVO4/BPQDs/OL-OEC with multiple components, each with definite functions, achieves a photocurrent density of 6.2 mA cm-2 at 1.23 V vs. reversible hydrogen electrode (RHE) under AM 1.5 illumination, offering a high-end standard approach for achieving efficient solar-to-fuel conversion devices by combining a photosensitizer and passivation layer.
Bibliographical noteFunding Information:
This work was supported by NSFC (22172077, 21902104), the Natural Science Foundation of Jiangsu Province of China (BZ2020063), NRF Korea (NRF-2019R1A2C3010479, NRF-2019M1-A2A2065612, NRF-2019M3E6A1064525, and 2019R1A4A1029237), Jiangsu International Science and Technology Cooperation Program (BZ2020063), and the Fundamental Research Funds for the Central Universities (No. 30921011216). J. H. P. acknowledges the support by Yonsei-KIST Convergence Research Program. The authors thank Y. G. and X.F.Y who participated in the discussions for analyzing the data obtained from the calculations.
© 2022 The Royal Society of Chemistry.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering