I want you to act as an academic journal editor Please Translate Chinese into English and rephrase the paragraph from an academic angle based on the writting style of the science journalM-N-C催化剂的发展历史始

The development of M-N-C catalysts can be traced back to Jansinski's discovery in 1964 that cobalt phthalocyanine, a type of metal chelate, exhibits ORR catalytic activity under alkaline conditions [13]. Subsequently, Jahnke et al. [14] summarized in detail the coordination configuration and catalytic activity of different transition metals forming chelates and proposed the importance of combining transition metal phthalocyanines with carbon carriers to enhance ORR catalytic activity and thermal activation. In 1989, a new breakthrough was achieved in the synthesis of M-N-C catalysts. Yeager et al. [15] reported a method for preparing M-N-C catalysts based on the thermal decomposition of a mixture of polyacrylonitrile, carbon, and transition metal salts, which used nitrogen-containing functional groups to form MNx coordination with transition metals. This work laid the foundation for the subsequent synthesis of a large number of M-N-C catalysts using different precursors.

Over the past few decades, the composition and properties of catalytic active sites have been a focus of debate among researchers. Representative hypotheses for several types of active sites are discussed here.

The first type of active site is the non-metallic site, which originates from studies on nitrogen-doped carbon, suggesting that nitrogen functional groups in carbon matrices act as active sites for reactions. Many studies have confirmed that nitrogen-doped carbon materials exhibit ORR catalytic activity [10635][10628][10641]. Nakamura et al. [10629] compared the active sites and performance of pyridine nitrogen and graphite nitrogen-based catalysts based on highly oriented pyrolytic graphite (HOPG) and concluded that the ORR active center in nitrogen-doped carbon materials is the carbon atom adjacent to pyridine nitrogen with Lewis basicity. Other studies suggest that the addition of metal ions promotes the generation of specific nitrogen species that play a major catalytic role. [ ]. Regarding the configuration of nitrogen sites, Liu et al. [10642] in 2009 believed that transition metals promote the entry of nitrogen into carbon substrates, increasing the electron-donating property of carbon matrices, and that catalysts containing more pyridine groups exhibit higher activity. Liu et al. [10640] in 2009 analyzed the nitrogen functional groups before and after stability testing and concluded that the ORR active center is the pyridine nitrogen and quaternary ammonium nitrogen functional groups [2012]. Kim et al. [10639] in 2014 found that adding transition metals increases the graphite nitrogen concentration in sp2-carbon networks, suggesting that graphite nitrogen is the active site for ORR.

The second type of active site is the MNx site, which emphasizes the role of the metal center in mediating the adsorption process of intermediates. Dodelet [10644] in 2000 used Time-of-Flight Secondary Ion Mass Spectrometry (ToF SIMS) to study the relative intensity of secondary ions in FeNC catalysts as a function of catalytic activity, confirming the importance of the FeN2C4+ structure for catalytic activity. Bouwkamp [10638] in 2002 investigated the influence of thermal decomposition temperature on the structure and activity of thermally decomposed carbon-supported transition metal chelate catalysts using in-situ Mössbauer spectroscopy and X-ray photoelectron spectroscopy. They found that as the thermal decomposition temperature increases, the FeN4 structure is finally preserved and is related to catalytic activity, demonstrating that the FeN4 structure participates in catalysis. Mukerjee et al. [10633] in 2015 identified three FeN4-like catalytic centers with different FeN conversion behaviors (Fe moving towards or away from the N4 plane) during the oxygen reduction reaction and demonstrated that ORR activity is controlled by the dynamic structure associated with the Fe2+/3+ redox transformation, linking the dynamic structure of MNxC sites during the chemical reaction process with catalytic activity.