Transition Metal-Modified Zirconium Phosphate Electrocatalysts for the Oxygen Evolution Reaction

Abstract

Zirconium phosphate (ZrP), an inorganic layered nanomaterial, is currently being investigated as a catalyst support for transition metal-based electrocatalysts for the oxygen evolution reaction (OER). Two metal-modified ZrP catalyst systems were synthesized: metal-intercalated ZrP and metal-adsorbed ZrP, each involving Fe(II), Fe(III), Co(II), and Ni(II) cations. Fourier transform infrared spectroscopy, X-ray powder diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy were used to characterize the composite materials and confirm the incorporation of the metal cations either between the layers or on the surface of ZrP. Both types of metal-modified systems were examined for their catalytic activity for the OER in 0.1 M KOH solution. All metal-modified ZrP systems were active for the OER. Trends in activity are discussed as a function of the molar ratio in relation to the two types of catalyst systems, resulting in overpotentials for metal-adsorbed ZrP catalysts that were less than, or equal to, their metal-intercalated counterparts.

Water Splitting Electrocatalysis within Layered Inorganic Nanomaterials

“…Our previous finding suggests that ZrP can serve as a support for transition metal-based OER catalysts and that the reaction occurs preferentially on the surface of the layered ZrP nanoparticles rather than the interlayer space [69]. Based on these results, we expected that exposing surface sites through exfoliation of ZrP could improve these catalytic systems.…”

“…Its ability to confine catalysts, high thermal stability, stability under a wide range of pH values, and its overall robustness are all desired for an ideal support. In our work, we intercalated the earth-abundant transition metal cations Fe 2+ , Fe 3+ , Co 2+ , and Ni 2+ into ZrP and assessed these composite materials as OER electrocatalysts [69].…”

“…The presence of the metals in these systems was confirmed by high resolution X-ray photoelectron spectroscopy (XPS). XPS was also used to determine the atomic concentration on both metal-modified ZrP systems, intercalated and adsorbed [69]. Due to the uptake of metal cations within the much larger area of the interlayers of ZrP rather than solely on the surface in the adsorbed case, XPS high resolution scans show that intercalated ZrP systems have higher atomic metal content when compared to adsorbed systems at similar M:ZrP ratios.…”

Phosphate‐Based Electrocatalysts for Water Splitting: Recent Progress

“…However, titanium phosphate can absorb sunlight, thus, most of Zr−Ti phosphates are used as photocatalysis material . Zirconium phosphate (ZrP) is generally used in conjunction with transition metal as electrocatalyst for water splitting, for example metal‐intercalated ZrP and metal‐adsorbed ZrP consisting of Ni 2+ , Fe 2+ , Fe 3+ and Co 2+ was active in OER for water oxidation in 0.1 M KOH and the activity of metal‐adsorbed ZrP is better than metal‐intercalated ZrP . Moreover, Zhao and co‐workers found that phosphate functionalized activated carbon (PAC) showed excellent electrocatalytic activity for the OER in an alkaline medium .…”

Engineering Ternary Copper-Cobalt Sulfide Nanosheets as High-performance Electrocatalysts toward Oxygen Evolution Reaction

“…By far, among the many hydrogen production methods (methane oxidation or reforming, etc. ), electrochemical water splitting is considered to be the most promising one at present, because it provides an apinoid strategy for renewable energy conversion and storage [7][8][9][10]. However, the semi-reaction in the process of water splitting, oxygen eVolution reaction (OER), is related to the continuous process of four proton-coupled electron transfer, which requires a higher overpotential at the anode and it therefore undergoes a sluggish reaction dynamics process [11][12][13].…”