“…Hollow microspheres are lightweight microparticles with spherically symmetric morphology, which have been adopted in a myriad of practical applications ranging from construction [ 1 , 2 , 3 , 4 ], transportation [ 5 , 6 , 7 ], chemical engineering [ 8 , 9 , 10 , 11 ], pharmaceutical research [ 12 , 13 , 14 , 15 ], and so forth. Due to their outstanding advantages in buoyancy performance [ 16 , 17 , 18 ], energy absorption [ 19 , 20 , 21 ], thermal/acoustic insulation [ 22 , 23 , 24 ], etc., ceramic hollow microspheres have shown great superiority as filler materials to regulate the performance of syntactic foam, which is a kind of classical composite material extensively used under various circumstances [ 25 , 26 , 27 , 28 ].…”