The cost-effective low-frequency ultrasound (42 kHz) producing bath type sonicator was utilized to demonstrate the synthesis of sequential (SP) and co-precipitated (CP) Ce0.9Pr0.1O1.95, Ce0.9Nd0.1O1.95 and their bare catalysts. The analytical characterizations of the catalysts showed that the 42 kHz ultrasound fetches the interesting physicochemical properties with unusual sonocatalytic efficiency in the resulting catalysts. In addition, the ultrasound introduced the nanoporous structure in the CeO2, Ce0.9Pr0.1O1.95 (SP, CP) and Ce0.9Nd0.1O1.95 (SP, CP) catalysts, however, the nanoporous structure was not observed for the bare praseodymium and neodymium oxides. The sonocatalytic efficiency of the catalysts was evaluated by studying the degradation kinetics of Acid Blue 113 (AB113) dye. The sonocatalytic degradation of AB113 followed the first-order kinetic rate law and the r2 (linear regression coefficient) was >0.92. The extended ultrasound irradiation of AB113 was studied for 7 h in the presence of various nanocatalysts in order to evaluate the total organic carbon (TOC) removal from the sonocatalytic microenvironment. The rapid development of cost-effective technology based on 42 kHz ultrasound assisted degradation of various environmental pollutants significantly contributes to reducing the cost required for the commercialization of advanced oxidation processes.