The hole trapping sites at the photoanode/electrolyte interface seriously detract from the positive effect of oxygen-vacancy on photoelectrochemical (PEC) water oxidation. In this work, a “patching” strategy is put forward to eliminate those charge trapping sites of the oxygen-deficient in disordered overlayer (DL) of WO3 photoanode by inactive pieces of oxygen-rich carbon nitride quantum dots (CNQDs). The “patching” leads to a 1.5-fold enhancement in PEC performance and a 100 mV cathodic shift of onset potential compared to the pre-optimized DL-WO3 photoanode. The remarkably raised charge transfer efficiency from 60% to 87% at 1.23 V vs RHE is an indication of boosting hole transfer. Density function theory (DFT) calculations reveal that DL-WO3/CNQDs produces a stepped valence band alignment together with the removal of charge trapping sites, is capable of overcoming the hole transfer limitation at the photoanode/electrolyte interface. This study might open a window to pursue a simple but highly efficient strategy on modification of solid/liquid interface for solar to fuel conversion.
Bibliographical noteFunding Information:
This work was supported by the NRF of Korea Grant funded by the Ministry of Science, ICT & Future Planning ( NRF-2019R1A2C3010479 , NRF-2019M1A2A2065612 , NRF-2019M3E6A1064525 ), NSFC ( 51802157 ), the Natural Science Foundation of Jiangsu Province of China ( BK20180493 ), K.-S. Lee acknowledges support by the Nano-Material Fundamental Technology Development program ( 2017M3A7B4049173 ) through the National Research Foundation of Korea (NRF) .
© 2019 Elsevier Ltd
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
- Electrical and Electronic Engineering