Design of bimetallic 3D-printed electrocatalysts via galvanic replacement to enhance energy conversion systems

3D-printing (also known as additive manufacturing) has recently emerged as an appealing technology to fight against the mainstream use of carbon-based fossil fuels by the large-scale, decentralized, and sustainable manufacturing of 3D-printed electrodes for energy conversion devices. Although promising strides have been made in this area, the tunability and implementation of cost-effective metal-based 3D-printed electrodes is a challenge. Herein, a straightforward method is reported to produce bimetallic 3D-printed electrodes with built-in noble metal catalysts via galvanic replacement. For this goal, a commercially available copper/polylactic acid composite filament has been exploited for the fabrication of Cu-based 3D-printed electrodes (3D-Cu) using fused filament fabrication (FFF) technology. The subsequent electroless deposition of an active noble metal catalyst (viz. Pd) onto the 3D-Cu surface has been carried out via galvanic exchange. A detailed electrochemical study run by scanning electrochemical microscopy (SECM) has revealed that the resulting bimetallic 3D-PdCu electrode exhibits enhanced capabilities by energy conversion related reactions —hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR)— when compared with the monometallic 3D-Cu counterpart. Thus, this simple functionalization approach provides a custom way for manufacturing functional metal-based 3D-printed electronics harboring noble metal catalysts to improve energy-converting applications on-demand and beyond.