Phytic acid-coated titanium as electrocatalyst of hydrogen evolution reaction in alkaline electrolyte

The phytic acid-coated titanium (IP6/Ti) electrode was prepared through a simple drop-drying process, with an aim of improving electrocatalytic activity toward the hydrogen evolution reaction (HER). Scanning electron microscope and X-ray photoelectron spectroscopy showed that the IP6 coated the substrate surface uniformly and completely. Evaluation of the electrode activity was carried out in 1.0 M NaOH by linear polarization, electrochemical impedance spectroscopy (EIS) and chronopotentiometry. The kinetic parameters obtained from Tafel curves reveal that the IP6 coating can enhance the exchange current density of the HER by 489 times compared to the bare Ti, and reduce the HER activation energy by nearly 50%. The EIS data prove that the charge transfer resistance of the HER was considerably reduced due to the IP6 coating, with a decrease in real surface area of the electrode. The catalytic effect of IP6 is due to an improvement in the charge transfer kinetics of the HER. This work indicates that IP6 may be a potent candidate as a catalyst for hydrogen energy production.

► A naturally occurring phosphorus compound was used as electrocatalyst of HER. ► Phytic acid coated Ti electrode was prepared through a simple drop-drying process. ► The prepared electrode shows excellent electrocatalytic activity toward HER. ► The catalytic effect is due to intrinsic electrocatalytic properties of phytic acid.