Iodide Oxidation Reaction Catalyzed by Ruthenium–Tin Surface Alloy Oxide for Efficient Production of Hydrogen and Iodine Simultaneously

Abstract

A new type of electrolysis by employing iodide oxidation reaction (IOR) via a ruthenium–tin surface alloy oxide (RuSn SAO) catalyst was designed to replace oxygen evolution reaction (OER) for efficient production of hydrogen, which not only enhances energy conversion efficiency but also produces a high-value commodity chemical, iodine, rather than O2, in the anodic cell. Remarkably, the excellent activity of RuSn SAO enables it to be the best catalyst for IOR toward energy-saving hydrogen production. Its two-electrode acidic electrolyzer requires a cell voltage of only 1.07 V to afford 10 mA cm–2, which is 0.51 V less than that required for OER to reach the same current density. Thus, the system drastically reduces energy consumption by more than 40% compared to pure water electrolysis. The chronopotentiometric test shows that the RuSn SAO needed a super-low overpotential increase of Δη = 70 mV at 10 mA cm–2 together with recorded highly durable stability in the acidic electrolyte, indicating enhanced catalytic activity. Furthermore, this strategy simultaneously produces hydrogen with ∼100% Faradic efficiency and a high-value commodity chemical, I2, making H2 production potentially costless. Thus, the proposed concept paves a new way to facilitate the realization of hydrogen economics.

High-performance Sb2S3 photoanode enabling iodide oxidation reaction for unbiased photoelectrochemical solar fuel production

“…Therefore, to improve the faradaic efficiency, the membrane that physically separates anodic and cathodic electrodes will be essential in real solar-driven HER system based on IOR. 7,51 Furthermore, an additional flowing system could prevent this photoelectrolysis system from photocurrent degradation derived from iodide exhaustion as well as increase in pH during overall reaction expressed as eqn (2). The effect of membrane and flowing system was similarly demonstrated in previous reports on AOR, such as glucose oxidation reaction, glycerol oxidation reaction.…”

“…S19a, ESI †). 51,55 When the electrolyte was exposed to only illumination without any electrochemical reactions, however, the color of electrolyte was slowly converted from yellow to orange after two weeks and to red after two months, implying sluggish kinetics of spontaneous oxidation of hydroiodic acid (Fig. S19b, ESI †).…”

Fast charge transfer between iodide ions and a delocalized electron system on the graphite surface for boosting hydrogen production

“…20 Also, it is also important to select alternative reactions to yield high value-added chemicals at low potentials in comparison with O 2 gas. In this direction, easily oxidizable chemicals such as alcohols, 21 urea, 22,23 hydrazine, 24 glucose, 25 methanol, 26 glycerol, 27 formate, 28 iron, 29 and iodide 30 have been demonstrated to selectively produce hydrogen and avoid the formation of O 2 . The iodide oxidation reaction (IOR) is an attractive aspect that involves the formation of high value-added I 2 by applying a suitable potential.…”

Efficient H2 Evolution Coupled with Anodic Oxidation of Iodide over Defective Carbon-Supported Single-Atom Mo-N4 Electrocatalyst

“…Nickel-doped cobalt hydroxide catalysts were used for IOR with a 10 mA cm –2 current density at 1.34 V . In addition, an alloy of ruthenium with a tin oxide catalyst shows a catalytic activity for IOR and maintains a 10 mA cm –2 current density at 1.07 V in the HClO 4 electrolyte …”

“…Nickel-doped cobalt hydroxide catalysts were used for IOR with a 10 mA cm −2 current density at 1.34 V. 8 In addition, an alloy of ruthenium with a tin oxide catalyst shows a catalytic activity for IOR and maintains a 10 mA cm −2 current density at 1.07 V in the HClO 4 electrolyte. 9 Single-atom catalysis has recently emerged as a promising candidate for a number of electrochemical reactions. It is because they have exceptional catalytic properties and high atom efficiency.…”