Porous carbon quantum dot as well as preparation method and application thereof

The invention relates to a porous carbon quantum dot as well as a preparation method and application thereof, and belongs to the technical field of carbon quantum dots. According to the preparation method of the porous carbon quantum dots, pulverized coal serves as a raw material, the raw material is low in cost and easy to obtain, then the pulverized coal is sequentially subjected to pyrolysis, acid pickling and solid-liquid separation treatment to obtain a first solution, a pore-forming agent is added into the first solution, the type of the pore-forming agent and the weight ratio of the pore-forming agent to the first solution are limited, and the porous carbon quantum dots are obtained. After at least one of ammonium chloride, zinc chloride and potassium hydroxide is mixed with a first solution, dehydration of alcoholic hydroxyl groups in solid residues and breakage of C-O bonds in phenol/ethers can be catalyzed, meanwhile, the substance has swelling and volatility and can be released through heat treatme