King Fahd University of Petroleum and Minerals

Khurram Saleem Joya

Muhammad Ali Ehsan

Catalytic materials useful, e.g., in water oxidation performing at low overpotential and/or stable for applications such as solar-to-fuel conversion systems may include nanoscale, nanoporous Pd-containing materials. Thin-film Pd electrocatalysts may be obtained via Aerosol-Assisted Chemical Vapor Deposition (AACVD) on conducting surfaces. XRD and XPS analyses show a phase pure crystalline metallic Pd deposit. Surface morphology study reveals a nanoparticulate highly porous nanostructure. Under electrochemical conditions, such Pd electrocatalysts may conduct water oxidation at onset potentials starting around 1.43 V against a reversible hydrogen electrode (η of 200 mV, Tafel slope of 40 mV/dec), and/or may achieve around 100 mA/cmcurrent density at 1.63 V against a reversible hydrogen electrode, and may exhibits long-term stability in oxygen evolution. Method of making such electrocatalysts and their uses are also provided.

Method for making a PD-coated electrode

An oxygen evolution reaction catalyst electrode may include: a glass electrode; a first coating, directly upon the glass electrode, comprising a layer of fluorine-doped tin oxide (FTO); and a second coating, directly upon the first coating, comprising a layer comprising at least 95 wt. % palladium, relative to a total weight of the second coating, wherein the palladium in the second coating is in the form of porous, spongy-textured clusters comprising palladium spheroid nanoparticles in cubic crystalline phase. The second coating may have a thickness in a range of from 0.5 to 10 &#x3bc;m, and the clusters may have an average largest dimension in a range of from 500 to nm.

Pd-comprising electrocatalysts suitable for water splitting

A noble metal-free water oxidation electrocatalyst can be stable and obtained from earth-abundant materials, e.g., using copper-colloidal nanoparticles. The catalyst may contain nanobead and nanorod morphological features with narrow size distribution. The onset for oxygen evolution reaction can occur at a potential of 1.45 V(&#x3b7;=220 mV). Such catalysts may be stable during long-term water electrolysis and/or exhibit a high electroactive area, e.g., with a Tafel slope of 52 mV/dec, TOF of 0.81 s, and/or mass activity of 87 mA/mg. The copper may also perform COreduction at the cathode side. The Cu-based electrocatalytic system may provide a flexible catalyst for electrooxidation of water and for chemical energy conversion, without requiring Pt, Ir, or Ru.

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Dhahran, Saudi Arabia

Khurram Saleem Joya