Controllable growth on nano-graphite-supported ZrO2–MnOx bimetallic oxides for electrocatalytic antibiotic degradation: mechanism to boost the Mn3+/Mn4+ redox cycle† Antibiotic contamination has become one of the most pressing problems in the field of water purification. Using nano-graphite (nano-G) as a carbon carrier, a ZrO2–MnOx/nano-G composite electrode with high catalytic activity was prepared by a hot pressing method based on MnOx/nano-G prepared by a sol–gel method.