Directly immobilizing a Ru–tannic acid linkage coordination complex on carbon cloth: an efficient and ultrastable catalyst for the hydrogen evolution reaction

Abstract

The hydrogen evolution reaction (HER) is a crucial step in electrochemical water splitting and thus demands durable and efficient catalysts. Here, we report a simple, practical and efficient coating method by using the one-step assembly of the natural polyphenol tannic acid (TA) and Ru^III coordination complex on an activated carbon cloth (ACC). Benefitting from the tight coordination between Ru^III and TA in alkaline medium, the Ru–TA/ACC catalyst made by this robust method demonstrates a superior stability with no deterioration of activity after 130 h of constant electrolysis. And the molecular dispersion of the Ru–TA linkage coordination complex ensures high HER catalytic efficiency in alkaline media. Typically, the Ru–TA/ACC catalyst exhibits an extremely low onset potential of nearly 0 mV and a tiny overpotential of 29 mV to achieve 10 mA cm⁻² in 1.0 M KOH solution. These performances are much better than those of the Pt/C catalyst, demonstrating its great potential for the replacement of Pt-based catalysts.