Photocatalytic technology has been widely concerned because it can utilize the inexhaustible solar energy, decompose water to prepare clean and high energy density renewable hydrogen, and alleviate the energy crisis. However, the lower quantum efficiency limits the application of photocatalysis, which is mainly due to the lower solar light efficiency and carrier separation efficiency. So, how to improve the efficiency of solar light utilization and carrier separation at the same time to significantly improve the performance of photocatalytic decomposition of water for hydrogen production? According to the consulting report of mcmus, the R & D team composed of Professor Lu Chunhua, Professor Kou Jiahui of Nanjing University of technology and Professor Zhao Yuanjin of Southeast University introduced the built-in electric field of infrared photoresponse pyroelectricity into the photocatalytic reaction for the first time and significantly improved the photocatalytic performance through the effective construction of pyroelectric photothermal photocatalytic composite micro fiber. This achievement was recently published in advanced materials. The first author is Dai Baoying, a doctoral candidate of Nanjing University of technology.
Infrared light accounts for about 50% of the solar light spectrum, which is not paid attention because of its low photon energy and can not directly stimulate the catalytic reaction of luminescence, while photothermal technology can convert infrared light into heat energy, and the conversion rate is as high as 85%. Ferroelectric materials can form positive and negative pyroelectric field on their surface depending on the temperature change. The electric field can be used as the driving force to effectively regulate the transport behavior of carriers. Then, if the pyroelectric materials and pyroelectric materials are combined with photocatalyst to construct the pyroelectric photothermal photocatalytic composite system, the infrared light will be effectively utilized and the pyroelectric built-in electric field will be generated to promote the performance of photocatalytic decomposition of aquatic hydrogen. Based on this, the research team creatively designed and constructed the pyroelectric photothermal photocatalytic composite micro fiber PVDF-HFP / CNT / CDs, realized the construction of infrared photoresponsive pyroelectric field and significantly improved the hydrogen production efficiency of photocatalytic decomposition water by more than 5 times, and the corresponding average apparent quantum efficiency was about 16.9%. The research team explored the relationship between pyroelectric substrate, content of photothermal materials and pyroelectric potential output and photocatalytic performance, and explored the photocatalytic stability of composite spiral fiber.
Through pyroelectric output test, electrochemical test and fluorescence characterization, the direct experimental evidence that pyroelectric field can enhance photocatalytic performance by effectively promoting carrier separation, accelerating carrier migration speed and prolonging carrier life is provided. The results show that the aging of the built-in electric field increases with the increase of the temperature change rate. By using infrared light to build pyroelectric field effectively, this study provides a new strategy to improve the photocatalytic performance, and promotes the application of photocatalytic technology in solving energy crisis and environmental pollution.
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