In-situ stabilizing surface oxygen vacancies of TiO2 nanowire array photoelectrode by N-doped carbon dots for enhanced photoelectrocatalytic activities under visible light

Publication date: February 2020Source: Journal of Catalysis, Volume 382Author(s): Shanpeng Li, Chunlei Liu, Ping Chen, Wenying Lv, Guoguang LiuAbstractOxygen vacancy was considered to act as electron scavengers, delaying electron-hole pair recombination for their critical impacts on the electronic-band structural modulation and optical absorption of a semiconductor. However, the generation and stabilization of oxygen vacancies (Vo) remains a considerable challenge. Herein, a N-doped carbon dots/Vo-rich TiO2 nanowire array (NCDs/TiO2 NA-Vo) photoelectrode with a stable oxygen vacancy layer in TiO2 energy band was constructed successfully by doping with NCDs. This optimized NCDs/TiO2 NA-Vo photoelectrode exhibited high activity and durability with a degradation reaction constant that was ∼ two and three fold higher than that of TiO2 NA-Vo and TiO2 NA electrodes, respectively, and maintained a high degradation efficiency after eight consecutive degradation cycles. Moreover, the NCDs/TiO2 NA-Vo photoelectrode demonstrated a photocurrent density of 0.56 mA cm−2, which was more than three times that of TiO2 NA electrode. These excellent visible light-driven photoelectrocatalysis (PEC) activities could be attributed to the stabilized and regulated oxygen vacancy layer induced by NCDs, which further accelerated the interfacial charge separation to generate more free radicals (e.g., OH, O2−, and 1O2) confirmed by electron-spin resonance (ESR) and Photoluminescence Spectr...
Source: Journal of Catalysis - Category: Chemistry Source Type: research