Ir‐Au Bimetallic Nanoparticle Modified Silicon Nanowires with Ultralow Content of Ir for Hydrogen Evolution Reaction

Abstract

Reducing the size and increasing the dispersity of the noble metals are effective ways to decrease the dosage and simultaneously increase their electrocatalytic activities for hydrogen evolution reaction (HER). The Ir−Au bimetallic nanoparticle modified silicon nanowires (Ir−Au−Si) with ultralow content of Ir are prepared and served to catalyze HER in the acid condition. The small Ir−Au nanoparticles are in‐situ grown and uniformly dispersed on the surface of silicon nanowires. Ir−Au−Si exhibits a significantly increased activity in HER catalysis compared with Ir−Si and Pt−Au−Si. Ir provides the active sites for HER, Au increases the electron transfer rate, and the silicon nanowires improve the speed of the hydrogen gas evolution. The optimal Ir−Au−Si‐2 shows a low Tafel slope of 24 mV dec−1 and high mass activity, which are better than those of Ir−Si and Pt−Au−Si catalysts.

One-Pot Synthesis of Alloy Ir–Cu Microspheres with Excellent Electro-Catalytic Activity Toward Oxygen Evolution Reaction under Acidic Conditions

“…Developing highly efficient and durable catalysts is crucial to renewable energy conversion and storage as well as water electrolyzers. − Oxygen evolution reaction (OER) as the anodic half reaction in these systems, has a vital role. − So far, a large amount of non-noble metal materials has been explored in the OER, such as cobalt-based and nickel-based. − The OER performance of nonprecious metals under alkaline conditions has been intensively studied. ,− Although non-noble metals have achieved some results, their catalytic activities had reached a certain level, it still did not perform well in the stability in the acidic environment. Acidic electrolytes have unique advantages in OER over alkaline electrolytes, for example, providing higher ionic conductivity. − However, just a few noble metals such as iridium and ruthenium can bear this critical environment, thus exhibiting good stability to OER under acidic conditions. , So far, iridium and ruthenium have been considered as irreplaceable OER materials under acidic conditions, which have lower overpotential and Tafel slopes, and have excellent stability. ,− …”

“…Although Ru noble metal nanocrystals (NCs) have better than Ir NCs OER activity under acidic conditions, their stability under acidic conditions is far less than that of Ir NCs, so the significance of OER for Ir NCs under acidic conditions is much greater than that of Ru. ,− The major restriction of iridium to wide application is the rare reserve of the element on the earth, so a popular strategy to decrease the utilization of iridium is to improve the catalytic activity of iridium by introducing a second metal . Alloying transition metals with iridium has been proved to be an efficient method to adjust the catalytic property .…”

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

“…It is noteworthy that the onset potential (-25 mV) of Ir/CeO 2 is still very close to Pt/C even after 20,000 CV cycle. Taking all these results together, one can conclude that Ir/CeO 2 modified GCE possess reasonably higher electrocatalytic activity and superior stability in HER as compared to the other reported catalysts in literature such as IrCo@NC-800 [39], Ir-Au-Si NCs [49], IrO 2 -Fe 2 O 3 [55] and Ir@NC [54].…”

Strategies for reducing the overpotential of one-dimensional Si nanostructured photoelectrodes for solar hydrogen production

“…Other platinum group metals such as Ru and Ir have also been used as HER co-catalysts for Si nanowire photoelectrodes. 88,89 Shao et al prepared Ru nanoparticles modified Si nanowire photoelectrode by reducing Ru ions by Si-H bonds. 88 The optimized Ru/Si nanowires exhibited low overpotential, good stability and low theoretical activation energy for HER.…”