School of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, 210016, Nanjing, China.
Integrated Energy Research Institute, Nanjing University of Aeronautics and Astronautics, 210016, Nanjing, China.
Chemphyschem. 2022 Jul 19;23(14):e202100851. doi: 10.1002/cphc.202100851. Epub 2022 May 19.
Artificial photoreduction of CO is vital for the sustainable development of human beings via solar energy storage in stable chemicals. This process involves intricate light-matter interactions, but the role of incident light intensity in photocatalysis remains obscure. Herein, the influence of excitation intensity on charge kinetics and photocatalytic activity is investigated. Model photocatalysts include the pure graphitic carbon nitride (g-C N ) and g-C N loaded with noble/non-noble-metal cocatalysts (Ag, TiN, and CuO). It is found that the increase of light intensity does not always improve the electron utilization. Overly high excitation intensities cause charge carrier congestion and changes the recombination mechanism, which is called the light congestion effect. The electron transport channels can be established to mitigate the light-induced effect via the addition of cocatalyst, leading to a nonlinear growth in the reaction rate with increasing light intensity. From experiments and simulations, it is found that the light intensity and active site density should be collectively optimized for increasing the energy conversion efficiency. This work elucidates the effect of light intensity on photocatalytic CO reduction and emphasizes the synergistic relationship of matching the light intensity and the photocatalyst category. The study provides guidance for the design of efficient photocatalysts and the operation of photocatalytic systems.
通过将太阳能储存在稳定的化学物质中，人工还原 CO 对于人类的可持续发展至关重要。这个过程涉及复杂的光物质相互作用，但入射光强度在光催化中的作用仍不清楚。本文研究了激发强度对电荷动力学和光催化活性的影响。模型光催化剂包括纯石墨相氮化碳（g-C3N4）和负载贵金属/非贵金属助催化剂的 g-C3N4（Ag、TiN 和 CuO）。研究发现，光强度的增加并不总是能提高电子利用率。过高的激发强度会导致载流子拥挤，并改变复合机制，这被称为光拥挤效应。通过添加助催化剂，可以建立电子输运通道来减轻光诱导效应，从而导致反应速率随光强度的增加呈非线性增长。通过实验和模拟发现，为了提高能量转换效率，应该综合优化光强度和活性位点密度。这项工作阐明了光强度对光催化 CO 还原的影响，并强调了匹配光强度和光催化剂种类的协同关系。该研究为高效光催化剂的设计和光催化系统的运行提供了指导。
