Platinum nanoparticle-doped recycled PLA filament for sustainable additive manufactured electrocatalytic architectures

Abstract

Additive manufacturing has the ability to facilitate the fabrication of advanced electrochemical architectures. To truly realise this, bespoke and high-performance filaments must be realised. This study presents a sustainable approach for developing highly conductive filament doped with platinum nanoparticles (PtNPs) and characterises them towards the hydrogen evolution reaction (HER). The PtNPs were synthesised using a green methodology, utilising aqueous conditions and graphite flakes as the only reducing agent. The PtNP-doped graphite was incorporated into recycled polylactic acid (rPLA)-based filaments, enabling the fabrication of highly conductive electrodes with enhanced electrocatalytic properties. The PtNPs-supported graphite (PtNPs-G) material was first characterised using SEM, EDX, XPS, and XRD, confirming the successful deposition of PtNPs. Next, electrochemical studies are performed using cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry, to demonstrate the enhanced electrochemical and electrocatalytic performance of the PtNPs-G electrodes. The optimised PtNPs-G(12%) electrode exhibited a HER onset potential of −0.04 V (vs. RHE), a Tafel slope of 46 mV dec⁻¹, and an overpotential of −312 mV at 10 mA cm⁻². Stability tests over 1000 linear sweep voltammetry cycles and 7-hour chronoamperometry demonstrated good durability, although minor performance degradation was attributed to known ingress tendency of the PLA matrix. The findings demonstrate the potential of additive manufacturing fabricated electrocatalysts for sustainable hydrogen production, reducing Pt usage while maintaining their high efficiency. This work highlights the versatility of additive manufacturing in developing cost-effective, customisable, and high-performance electrochemical devices for renewable energy applications.