A systematic exploration of mapping knowledge domains for free radical research related to coal

In order to better grasp the development and trends of free radical research related to coal. Based on 820 publications collected from the core collection database of Web of Science (WoS), this paper systematically analyzed the free radicals research related to coal through the method of bibliometrics, and used VOSviewer and CiteSpace to plot knowledge domain maps. The results indicate that this research topic has gone through four stages of budding, slow development, accelerated development, and rapid development, the current number of papers is increasing exponentially. The better development and utilization of coal resources is the driving force for the development of this research field, and the exploration of coal structure and reactivity is a key first step. Coal spontaneous combustion and prevention, co conversion and utilization of coal-biomass, coal pyrolysis, environmental hazard and coal geochemistry are the five main research branches in this field, which have expanded from the macro level to the micro level. The first three research branches among them are the most popular and will continue to receive more attention in the future. In addition, we further revealed the emergence and evolution of various research branches and identified their research frontiers.