Voltammetry Zoo: A 3D-Printed Electrode Laboratory Activity for Teaching Electrochemistry in Secondary Education

Abstract Electrochemistry is often perceived as a conceptually challenging topic, particularly at the secondary school level, due to the abstract nature of processes occurring at the electrode–solution interface. To address this, we present the “Voltammetry Zoo”, an inquiry-based laboratory activity that uses low-cost, 3D-printed animal-shaped electrodes to introduce key electrochemical concepts in an engaging and accessible manner. Electrodes fabricated from carbon black–polylactic acid (CB/PLA) were designed to have a similar surface area but differing geometries, enabling students to investigate how electrode shape influences electrochemical response using cyclic voltammetry of ferrocenemethanol. Students compare current responses across different electrode designs, encouraging hypothesis-driven learning and the exploration of structure–function relationships. Experimental results show a strong positive correlation between anodic peak current and electrode perimeter, while peak-to-peak separation remains independent of geometry. Additional activities, including scan rate analysis and copper electrodeposition, provide visual and quantitative insights into diffusion-controlled processes and electroactive surface regions. Classroom implementation with secondary school students demonstrated high levels of engagement and accessibility, although conceptual understanding of voltammetry varied, highlighting opportunities for further instructional scaffolding. Overall, this activity integrates digital fabrication, visualization, and electrochemical analysis to support student understanding of mass transport, electron transfer, and the influence of electrode design on analytical signals.