Electrocatalytic Hydrogen Evolution Reaction of Rhenium Metal and Rhenium‐Based Intermetallic in Acid and Alkaline Media

Abstract

Rhenium (Re) metal has been well known for the high corrosion resistance in strong acid and alkaline electrolyte, which makes it a potential electrocatalyst toward hydrogen evolution reaction (HER). However, the low HER activity (>100 mV @ 10 mA/cm2) is a fatal flaw and the reason Re metal does not receive much attention comparing to other noble metal such as Platinum (Pt), Iridium (Ir) and Ruthenium (Ru). To improve the HER activity of Re metal, in this work, we have incorporated a small amount of Zr atoms into Re lattice to form Re based intermetallic Zr5Re24. The large Zr atoms can expand the subunits of the structure and increase the Re−Re bond lengths while the low electronegativity of Zr atoms will donate electrons to Re atoms and fill more antibonding state of Re−Re bond. Both crystal‐structural and electronic‐structural factors will reduce the bond strength of Re−Re bond and thus weaken the corresponding hydrogen adsorption energy (ΔGHad). This can adjust the ΔGHad of Zr5Re24 to an optimal position and enhance the HER activity from Re metal (η10∼125 mV) to Zr5Re24 (η10∼90 mV). Moreover, it was realized that OH molecule on the surface of Zr5Re24 and Re metal will not occupy the most active site (i. e. poison effect) nor significantly influence the ΔGHad to the optimized position (i. e. 0 eV), which well elucidate the similar HER activity in acid or alkaline electrolyte.

Function of Internal and External Fe in a Ni-Based Precatalyst System Toward Oxygen Evolution Reaction

“…The crystal structure and purity of the as-synthesized Ni 3– x Fe x P ( x = 0, 0.5, 1) series were investigated using a Bruker D8 ADVANCE powder X-ray diffractometer (XRD, Cu K α1 : λ = 1.54056Å) with 2θ ranging from 30 to 60 ° at a scan rate of 5 °/min. The experimental data was compared with the simulated pattern from the Inorganic Crystal Structure Database (ICSD). ,, To examine the contents of Ni and Fe in the as-synthesized Ni 3– x Fe x P series, Zeiss Supra55, a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray detector (EDX, accelerating voltage: 30 keV), was employed to probe the morphology and chemical composition of each sample. In order to reconfirm the chemical compositions of the samples after chronoaperometry measurement, around 30 mg of each sample was dissolved in aqua regia (concentrated nitric acid/concentrated hydrochloric acid = 1:3) to determine the ratio of the corresponding elements using the inductively coupled plasma mass spectrometry (ICP-MS) technique.…”

The Influence of Electrode Constituents on Hydrogen Evolution Reaction on Phosphate W- and Mo-Bronze-Based Electrodes

“…According to Trassati's volcano plot [16], rhenium has the required intermediate bonding energy value. So far, rhenium showed very low HER activity, but promising Re-intermetallic electrocatalysts have been investigated [17].…”

Balance between Activity and Stability of Single Metal and Intermetallic Compounds for Electrocatalytic Hydrogen Evolution Reaction

“…In addition, based on our previous work, alloying Zr and Re in the system can demonstrate similar HER activity in both acidic and alkaline electrolytes because the OH poison effect and the change of ΔG H with neighbored OH are not profound. 32 The combination among Re, Ru, and Zr metals to form binary/ternary intermetallic compounds may have the opportunity to break the balance between the activity and stability of HER for using a single metal. Accordingly, a series of compounds, ZrRe 2 , ZrRu 2 , and ZrRe 1.75 Ru 0.25 , was targeted as HER electrocatalysts to testify to the above strategy.…”

“…This way, it may display high HER activity while maintaining stability during long-term operation. In order to further boost HER efficiency, Zr metal with low electronegativity (χ = 1.33, Pauling scale) and high corrosion resistance to acid or alkaline electrolytes was also incorporated in the system. − Zr belongs to the early transition metals, and bonding between Zr and Ru/Re atoms will be in a bonding state that can strengthen phase stability. In addition, based on our previous work, alloying Zr and Re in the system can demonstrate similar HER activity in both acidic and alkaline electrolytes because the OH poison effect and the change of Δ G H with neighbored OH are not profound .…”

“…In order to further boost HER efficiency, Zr metal with low electronegativity (χ = 1.33, Pauling scale) and high corrosion resistance to acid or alkaline electrolytes was also incorporated in the system. − Zr belongs to the early transition metals, and bonding between Zr and Ru/Re atoms will be in a bonding state that can strengthen phase stability. In addition, based on our previous work, alloying Zr and Re in the system can demonstrate similar HER activity in both acidic and alkaline electrolytes because the OH poison effect and the change of Δ G H with neighbored OH are not profound . The combination among Re, Ru, and Zr metals to form binary/ternary intermetallic compounds may have the opportunity to break the balance between the activity and stability of HER for using a single metal.…”