Provoking electrocatalytic activity with bio-molecules at inactive gas diffusion layers

Developments of earth abundant and highly active metal-free electrocatalysts pave a new way for nurturing economically viable water splitting for hydrogen production. Recent findings showed that deoxyribose nucleic acid (DNA) can be employed to reduce the loading of expensive catalysts like Pt and to increase the catalytic activity of catalysts in the streams of hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) respectively. Herein, for the very first time, we found an interesting property of DNA in electrocatalysis by a simple and fast physical modification over the gas diffusion layers (GDL). The DNA molecule while embedded over the GDL surface, it has modified the surface phenomenon in addition to the active functional groups to give the electrocatalytic activity. The DNA modified GDL (DGDL) has showed better kinetic trend and activity in both oxygen evolution reaction (OER) and HER in alkaline and acidic media respectively. To further ensure the nature of these surface modified GDL, we have utilized other important bio-molecules also and studied their activity in comparison with DNA. For that, we have chosen carboxymethyl cellulose (CMC) and bovine serum albumin (BSA) bio-molecules for the same. In OER in 1 M KOH, to reach 10 mA cm(-2) current density, DGDL required an overpotential of 384 mV compared to CGDL and BGDL which required 402 and 414 mV respectively. Similarly, for HER too, for attaining 10 mA cm(-2), DGDL, CGDL and BGDL required over-potentials 298, 369 and 393 mV respectively. The increase in activity was owing to the presence of surface functionalities that facilitated improved charge transfer kinetics and electrode-electrolyte interaction in an efficient manner. With these fruitful findings in activities, in futuristic, our proposed route can be extended to design various other smart, cost effective and self-standing metal free catalysts in a facile way. (C) 2019 Elsevier Ltd. All rights reserved.