Employing DNA scaffold with rhenium electrocatalyst for enhanced HER activities

Abstract

The replacement of Pt based catalysts for HER is still being a bottleneck and efforts have been made for finding new catalysts and here Rhenium nanoparticles (NPs) with the backing of bio-molecule deoxyribonucleic acid (DNA) was prepared as stable solutions. Depending upon the variation in the concentrations of DNA, two stable solutions namely, Re@DNA (0.055 M) and (0.083 M) were prepared. The formed Re NPs were in ultra-lesser size of 5 nm and with chain-like entities. The Re@DNA was stable as solution and directly drop-casted for electrochemical HER studies in 0.5 M H2SO4. The exploitation of DNA here as a scaffold avoids external binders and itself acted as a binder in HER studies. The HER studies revealed that for reaching 10 mA cm−2 current density, Re@DNA (0.055 M) showed lesser overpotential of 228 mV with a Tafel slope value of 137 mV/dec. Cycling study showed the activation of catalysts that is evidenced from the calculated ECSA from the post HER Cdl studies. Moreover, the overpotential required at 10 mA cm−2 was reduced to 152 mV which indicates high active nature of the Re@DNA. The post HER study revealed the stable nature of chain like structures of Re@DNA along with exposed sites after continuous cathodization.