Gas diffusion substrate and electrode

A process for the preparation of a gas diffusion substrate, wherein said substrate comprises (i) an electrically conducting porous structure, and (ii) a first catalytic component, said process comprising in-filling a pre-formed electrically conducting porous structure with the first catalytic component to embed the first catalytic component within the electrically conducting porous structure, wherein the first catalytic component (1) is a gas-phase catalyst designed to remove contaminant gases, and (2) comprises a first catalyst which is one or more noble metals or non-noble metals or a combination thereof, and wherein said first catalyst is directly supported on an electrically non-conducting support.

A process for the preparation of a gas diffusion electrode, wherein said electrode comprises (i) an electrically conducting porous structure, (ii) a first catalytic component, and (iii) a second catalytic component, said process comprising:

• (1) in-filling a pre-formed porous structure with the first catalytic component to embed the first catalytic component within the electrically conducting porous structure and (2) applying the second catalytic component to the electrically conducting porous structure as a surface layer;
• wherein the first catalytic component (1) is a gas-phase catalyst designed to remove contaminant gases, and (2) comprises a first catalyst which is one or more noble metals or non-noble metals or a combination thereof, and wherein said first catalyst is directly supported on an electrically non-conducting support, and
• wherein the second catalytic component (1) is an electrocatalyst adapted to facilitate an electrochemical reaction, and (2) comprises a second catalyst which is a precious metal or a transition metal as a metal or a metal oxide, and wherein the second catalyst is either unsupported or supported in a dispersed form on a carbon support, an organic complex in the form of a high surface area finely divided powder or fibre, or a combination thereof.