Disclosed herein is an electrode material comprising a carbon-containing substrate, comprising a surface and a plurality of R.sub.F moieties wherein each R.sub.F moiety is covalently bound to the surface; and each R.sub.F moiety comprises a fluorine atom. Also, disclosed herein is a method of preparing an electrode material.

A cathode for water splitting production includes: (1) a porous substrate; and (2) an electrocatalyst affixed to the porous substrate. The electrocatalyst includes heterostructures of a first material and a second material that partially covers the first material.

The present invention concerns an electrode element having a valve metal substrate, a first catalyst component applied to said substrate, said first catalyst component suitable for evolving oxygen from an aqueous solution under anodic polarization, a second catalyst component suitable for generating chlorine dioxide from a chlorate solution in acidic environment; said first and second catalyst component being electrically insulated from each other. The inventions also concern an electrolytic cell having such an electrode element and a process for the generation of chlorine dioxide on a catalyst component an electrochemical cell comprising such an electrode element.

The present invention discloses porous covalent organic frameworks (COF) supported noble metal-free nanoparticles which are useful as electrocatalysts for a water splitting system, and to the process for preparation of such electrocatalysts. The covalent organic frameworks (COF) supported noble metal-free nanoparticles have general formula (I):
COF_AxBy(M)n(Formula I) wherein COF is selected from a Tris (4-formylphenyl)amine terephthaldehyde polymer or a benzimidazole-phloroglucinol polymer; A and B each independently represent a transition metal selected from the group consisting of Ni, Co, Fe, Mn, Zn, and mixtures thereof; or A and B together represent a transition metal selected from the group consisting of Ni, Co, Fe, Mn, Zn, and mixtures thereof; M represents hydroxide or a nitride ion; x and y represent the weight % of the metal loadings; or a ratio of x:y is between 0:1 and 1:0; and n is an integer 1 or 2 or 3.

A water purification anode has a first semiconductor contacting a second semiconductor at a heterojunction. The second semiconductor includes TiO.sub.2 and excludes bismuth and niobium. The first semiconductor includes iridium. In some instances, the anode includes a current collector in direct physical contact with the first semiconductor. The anode can be arranged in water such that at least one face of the second semiconductor is in direct physical contact with the water.

In exemplary implementations of this invention, a photoelectrode includes a semiconductor for photocarrier generation, and a catalyst layer for altering the reaction rate in an adjacent electrolyte. The catalyst layer covers part of the semiconductor. The thickness of the catalyst layer is less than 60% of its minority carrier diffusion distance. If the photoelectrode is a photoanode, it has an OEP that is more than the potential of the valance band edge but less than the potential of the Fermi level of the semiconductor. If it is a photocathode, it has an RHE potential that is less than the potential of the conduction band edge but more than the potential of the Fermi level of the semiconductor. The absolute value of difference (OEP minus potential of valence band edge, or RHE potential minus potential of conduction band edge) is greater than zero and less than or equal to 0.2V.