Ultrasonically Surface-Activated Nickel Foam as a Highly Efficient Monolith Electrode for the Catalytic Oxidation of Methanol to Formate

Abstract

Most of the current electrocatalysts for the methanol oxidation reaction are precious group metals such as Pt, Pd, and Ru. However, their use is limited due to their high cost, scarcity, and issues with carbon monoxide poisoning. We developed a simple method to prepare a nickel foam (NF)-based monolith electrode with a NiO nanosheet array structure as an efficient electrocatalyst toward the oxidation of methanol to produce formate. By a simple ultrasonic acid treatment and air oxidation at room temperature, an inert NF was converted to NiO/NF as a catalytically active electrode due to the uniform NiO nanosheet array that was rapidly formed on the surface of NiO/NF. In alkaline electrolytes containing methanol, the as-prepared NiO/NF catalysts exhibited a lower methanol oxidation reaction (MOR) potential of +1.53 V vs RHE at 100 mA cm −2 compared to that of inert NF samples. The difference in potentials between the E MOR and the E OER at that current density was found to be 280 mV, indicating that methanol oxidation occurred at lower potentials as compared to the oxygen evolution reaction (OER). We also observed that the NiO/NF could also efficiently catalyze the oxidation of CO without being poisoned by it. NiO/NF retained close to 100% of its initial activity after 20,000 s of methanol oxidation tests at high current densities above 200 mA cm −2 . Because of the simple synthesis method and the enhanced catalytic performance and stability of NiO/NF, this allows methanol to be used as an OER masking agent for the energy-efficient generation of value-added products such as formic acid and hydrogen.

Electrochemical Proton Reduction over Nickel Foam for Z‐Stereoselective Semihydrogenation/deuteration of Functionalized Alkynes

“…HCl (Figure 1a). [57] After recycling and washing the Ni foam for 11 catalytic cycles, the surface of the Ni foam looked similar to the fresh Ni foam (Figure 1b). This shows that the structure of Ni foam is intact, and the multiple catalytic cycles do not affect it.…”

In Situ Reconstructed Zn doped FexNi(1−x)OOH Catalyst for Efficient and Ultrastable Oxygen Evolution Reaction at High Current Densities

“…[ 1 ] The weak peak at 900 cm −1 is associated with NiO in a tiny amount, [ 30 ] which should be derived from the oxidized NF during sample preparation, since the NF surface is often oxidized spontaneously when immersed in a solution that contains oxidants, such as Fe 3+ or dissolved oxygen. [ 31 ] Therefore, the NF support for fresh‐prepared Zn‐(Ni/FeOOH)@NF involves the partially oxidized NF (NiO/NF). In addition, no peaks from Zn related compounds are detected, which may suggest that Zn exists as dopant in Zn‐(Ni/FeOOH)@NF.…”

Performance Improvement of Gold Electrode towards Methanol Electrooxidation in Akaline Medium: Enhanced Current Density Achieved with Poly(aniline-co-2-hydroxyaniline) Coating at Low Overpotential

“…The anodic peak current is proportional to sweep rate in the studied range of 25-200 mV/s, as shown in Figure 6B. The concentration of redox species on the surface of the PACHA coated electrode and active surface area of the coated electrode can be estimated from the slope of anodic current vs. scan rate plot [62,63]. Alternatively, using the Randles-Sevick equation diffusion coefficient can be calculated from slope of anodic peak current versus square root of the seep rate.…”