Expanding the Toolbox of Multi-Material Three-Dimensional-Printed Electrochemical Flow Cells Fabricated in a Single Step: Impinging Jet, Mixing and Dilution, and Dual-Electrode Generator-Collector Electrochemical Cells.

Hydrodynamic electrochemical cells have broad utility in sensing, electrocatalysis, mechanistic studies, and electroanalysis. Here, we report on the expansion of hydrodynamic electrochemical devices that can be fabricated using 3D printing beyond channel flow electrodes to include impinging jet electrodes, a dilution/mixing circuit for in-channel detection of electroactive species, and dual-electrode generator-collector cells. These examples highlight the ability of 3D printing to produce intricate structures with internal voids, enhance analytical functionality, and enable sophisticated operations such as fluid mixing and generation-collection in simple, monolithic devices that do not require alignment, clamping, or assembly. To promote adoption by the wider electrochemical community, we provide printable .stl files as part of the manuscript. Device performance was evaluated in both stagnant and flowing solutions of ferrocene methanol, an outer-sphere redox mediator suitable for characterizing the transport characteristics and electrochemical performance of the devices. All devices exhibited responses consistent with Levich behavior for their respective geometries. The mixing circuit achieved 100-fold dilutions with results in excellent agreement with solutions prepared using volumetric glassware, while the generator-collector cell demonstrated high collection efficiencies under optimized conditions. These results establish 3D printing as a versatile, accessible approach for fabricating hydrodynamic electrochemical devices with advanced capabilities and pave the way for customizable, high-performance devices suitable for electroanalysis, electrocatalysis, and sensing applications.