General and robust photothermal-heating-enabled high-efficiency photoelectrochemical water splitting

• Main Authors: He, Bing, Jia, Songru, Zhao, Mingyang, Wang, Yang, Chen, Tao, Zhao, Shiqiang, Li, Zhen, Lin, Zhiqun, Zhao, Yanli, Liu, Xueqin
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Materials; Bismuth Vanadate; Photoanodes
• Online Access: https://hdl.handle.net/10356/160727
• Institution: Nanyang Technological University

The ability of photoanodes to simultaneously tailor light absorption, charge separation, and water oxidation processes represents an important endeavor toward highly efficient photoelectrochemical (PEC) water splitting. Here, a robust strategy is reported to render markedly improved PEC water splitting via sandwiching a photothermal Co3 O4 layer between a BiVO4 photoanode film and an FeOOH/NiOOH electrocatalyst sheet. The deposited Co3 O4 layer manifests compelling photothermal effect upon near-infrared irradiation and raises the temperature of the photoanodes in situ, leading to extended light absorption, enhanced charge transfer, and accelerated water oxidation kinetics simultaneously. The judiciously designed NiOOH/FeOOH/Co3 O4 /BiVO4 photoanode renders a superior photocurrent density of 6.34 mA cm-2 at 1.23 V versus a reversible reference electrode (VRHE ) with outstanding applied bias photon-to-current efficiency of 2.72% at 0.6 VRHE . In addition to the metal oxide, a wide variety of metal sulfides, nitrides, and phosphides (e.g., CoS, CoN, and CoP) can be exploited as the heaters to yield high-performance BiVO4 -based photoanodes. Apart from BiVO4 , other metal oxides (e.g., Fe2 O3 and TiO2 ) can also be covered by photothermal materials to impart significantly promoted water splitting. This simple yet general strategy provides a unique platform to capitalize on their photothermal characteristics to engineer high-performing energy conversion and storage materials and devices.