Binder- free iridium based electrocatalysts: Facile preparation, high activity and outstanding stability for hydrogen evolution reaction in acidic medium

Abstract

Herein, we develop various iridium based catalysts using titania, zirconia and ceria as a supporting material (Ir/MO 2 ; M = Ce, Ti, Zr) for hydrogen evolution reaction (HER). To investigate their electrocatalytic activities, glassy carbon electrodes (GCE) were modified by drop casting the catalyst ink without using any binder. Linear sweep voltammetry (LSV) was used to test their electrocatalytic activities in 0.5 M H 2 SO 4 solution. Among these catalysts, Ir/CeO 2 was found to exhibit excellent activity and superior stability. According to the polarization curves, onset potential (g 0 ) and overpotential (g@10 mA.cm À2 ) of Ir/CeO 2 were found as À13 and À23 mV, respectively, which are lower than the values obtained for commercial 10% Pt/C catalyst. Moreover, Ir/CeO 2 provides low Tafel slope (38.7 mV.dec -1 ), high turnover frequency (1.95 @100 mV) and high exchange current density (2.69 mA.cm À2 ) values. In addition, Ir/CeO 2 shows superior stability even after 20 000 cycle in acidic environment (pH = 0.3) which makes Ir/CeO 2 (2.44 wt% Ir) as a promising alternative electrocatalyst for HER.

NiMo/CoMoO4 Heterostructure with Confined Oxygen Vacancy for Active and Durable Alkaline Hydrogen Evolution Reaction

“…From Figure f, the Tafel slope values demonstrated the following trend: NiMo/CoMoO 4 (92 mV dec –1 ) < CoMoO 4 (99 mV dec –1 ) < NiMo (108 mV dec –1 ). From more accurate results, we can claim that the hydrogen evolution mechanism on the as-prepared materials proceeds via Volmer–Heyrovsky (120–40 mV dec –1 ) . More importantly, the EIS data recorded at 0.0 V vs RHE exhibited that NiMo possesses the minimum charge transfer resistance ( R ct = 244.8 Ω), followed by NiMo/CoMoO 4 ( R ct = 301.5 Ω), and CoMoO 4 ( R ct = 463 Ω).…”

“…From more accurate results, we can claim that the hydrogen evolution mechanism on the as-prepared materials proceeds via Volmer−Heyrovsky (120− 40 mV dec −1 ). 62 More importantly, the EIS data recorded at 0.0 V vs RHE exhibited that NiMo possesses the minimum charge transfer resistance (R ct = 244.8 Ω), followed by NiMo/ CoMoO 4 (R ct = 301.5 Ω), and CoMoO 4 (R ct = 463 Ω). All fitted data, based on the equivalent circuit, was tabulated for each sample and can be found in Tables S2−S4.…”

Highly efficient and durable P, Ru–CeO2 self-supporting electrodes toward industrial-level hydrogen production

“…No impurity peaks are appearing in the XRD pattern of P, Ru–CeO 2 , implying that the incorporation of both Ru and P atoms does not alter the crystal structure of CeO 2 . 39 Raman spectroscopy is used to analyze the interaction between active sites and substrates. As shown in Fig.…”

The Utilization of Iridium Nanoparticles Impregnated on Metal Oxides (Ceria, Titania, and Zirconia) with a Simple and Ecologically Safe Synthesis Approach in Oxygen Evolution Reactions

“…They also facilitate the charge transfer during the reaction and increase the surface volume ratio by increasing the electrochemical surface area. These metal oxides have been widely employed in a large variety of chemical reactions such as OER, 9 HER, 20,21 hydrogen generation from ammonia borane, 22 and formic acid oxidation, 23 which motivates us to use ceria, titania, and zirconia, as metal oxides support.…”