The annual publication of scientific publications can intuitively show the research scale and development trend of POM-based photocatalysts. The first article in the database was published in 1991. i.e. "Polyoxometalate Chemistry: An Old Field with New Dimensions in Several Disciplines" by Michael T. Pope and Achim Müller. They reviewed the history of POMs over the past 100 years and prospected their new development trend of POMs. The introduction explains that POMs are widely used in photocatalysis and clinical chemistry due to their unique properties. Between 1991 and 2001, there was a relatively slow pace of development in this area, known as the "precursory phase", with only 22 cumulative publications. In 2002, 15 valid papers were published, and the number of publications exceeded 10 for the first time in history. This means POM-based photocatalysts began to attract the attention of researchers. Annual publication generally shows an upward trend, except for small fluctuations in individual years. Further, the increase has accelerated significantly since 2014, with more than 100 publications annually. The most significant number of papers published annually appeared in 2021, with 155 papers. In the past two years, even though the spread of the new coronavirus has had a nonnegligible impact on the scientific work of most researchers, the annual number of publications remains stable. From the trend in Figure (a), the research scale of POM-based photocatalysts will remain relatively active in the next few years.