Transforming Discarded Thermoelectrics into High-Performance HER Catalysts

TL;DR

This study transforms thermoelectric waste into efficient HER electrocatalysts using scalable methods, demonstrating improved performance and supporting the approach with theoretical calculations.

Contribution

It introduces a novel, low-carbon method to convert thermoelectric waste into high-performance HER catalysts with enhanced activity.

Findings

TE waste-M shows lower overpotential (641 mV) than TE waste-BM.

TE waste-M exhibits a smaller Tafel slope (233 mV/dec) and stable operation for 5.5 hours.

Heterostructure formation enhances HER activity supported by DFT calculations.

Abstract

With the increase in the complexity of the materials used in various sophisticated electronic devices, recycling of E-waste is becoming challenging. In the present study, we have converted thermoelectric (TE) waste into functional HER electrocatalyst by considering circular-economy and low-carbon approach. The as received TE waste was processed through ball milling (TE waste-BM) and melting casting (TE waste-M) routes. Morphological and structural evaluations revealed that the formation of BiSbTe3/ZnTe heterostructure in TE-waste-M promote HE efficiency when compared to the presence of Bi2Te3/BiSbTe3 heterostructure (TE-waste-BM). TE waste-M exhibited lower overpotential (641 mV at 10 mA/sq.cm), smaller Tafel slope (233 mV/dec) and stable operation for 5.5 h with negligible current decay than that of TE waste-BM, attributed to the accelerated charge transfer, fast water dissociation steps and rapid hydrogen adsorption in TE waste-M, originated from the presence of BiSbTe3/ZnTe heterostructure, defect enriched interfaces. Density functional theory calculations supported the experimental findings, revealing that heterostructures strengthens the bonding states near the Fermi level, thereby enhancing the HER activity of BiSbTe3/ZnTe heterostructure. This work simultaneously integrates waste management with green hydrogen production by offering an economically viable, scalable and low-carbon approach for HER catalysts.