Strained carbon steel as a highly efficient catalyst for seawater electrolysis

Abstract

In response to the global energy crisis, water splitting has become one of the most efficient methods to produce hydrogen as an excellent substitute for fossil fuels. The diffusion coefficient of hydrogen and its interaction with iron have granted carbon steel (CS) the susceptible nature to hydrogen, and therefore CS is considered a promising electrocatalyst in the hydrogen evolution reaction. Compared to many traditional alkaline electrolytes, simulated seawater exhibits reasonable performance that facilitates an effective hydrogen evolution reaction. In the electrolysis of simulated seawater, the lowest overpotential of strained CS samples (-391.08 mV) is comparable to that of Pt plate electrodes (-377.31 mV). This is the result of the plane strain introduced to CS samples by a hydraulic press and indentation, which help to facilitate mass transport through diffusion for hydrogen evolution. The susceptibility of CS is verified by the formation of nanoscale hydrogen blisters that form in the proximity of grain boundaries. These blisters are the result of hydrogen gas pressure that is built up by the absorbed atomic hydrogen. These hydrogen atoms are believed to accumulate along the CS {1 1 0} planes adjacent to grain boundaries. CS has so far not been studied for the catalysis of water splitting. In this study, CS is used as an electrocatalyst for the first time as a cost-effective method for the utilization of seawater that further contributes to the promotion of green energy production.