Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.
Angew Chem Int Ed Engl. 2021 Sep 27;60(40):21728-21731. doi: 10.1002/anie.202108769. Epub 2021 Aug 26.
Photo/electrocatalytic ammonia synthesis has recently developed fast while the ammonia yields over state-of-the-art photo/electrocatalysts are still very moderate. Such low concentration of synthesized NH3 brings about a challenge to the reliable quantification of the product in photo/electrocatalysis. Notably, we found that the quantitative detection of ammonia concentration below 0.2 ppm is error-prone, which is likely the case happening in the majority of photo/electrocatalytic NH3 synthesis, thus arising concerns about the rationality and accuracy for low-concentration ammonia quantification in these processes. Herein, we discuss the methodology used and analyze the reliability of various detection methods for the detection of trace ammonia in aqueous media. The challenges facing the detection of low concentration of ammonia in photo/electrocatalysis can be overcome by integration with multiple detection methods. According to the data presented, we also propose an effective criterion for precise quantification of ammonia, avoiding the unreasonable comparisons in photo/electrocatalytic ammonia synthesis.
光电催化氨合成最近发展迅速，然而，最先进的光电催化剂的氨产率仍然非常适中。如此低浓度的合成 NH3 给光电催化中产物的可靠定量带来了挑战。值得注意的是，我们发现，低于 0.2ppm 的氨浓度的定量检测容易出错，这很可能是大多数光电催化 NH3 合成中发生的情况，因此人们对这些过程中低浓度氨定量的合理性和准确性产生了担忧。在此，我们讨论了所使用的方法，并分析了各种检测方法在检测水相中的痕量氨时的可靠性。通过与多种检测方法相结合，可以克服光电催化中检测低浓度氨所面临的挑战。根据所提供的数据，我们还提出了一个用于精确定量氨的有效标准，避免了光电催化氨合成中不合理的比较。
