Ceramic proton-conducting membranes

A method of forming a ceramic selective membrane, the method comprising:

• applying a ceramic precursor sol to a porous membrane substrate;
• and
• gelling the ceramic precursor sol, using a sol-gel process, to form a selective silica ceramic from the ceramic precursor sol, thereby providing a ceramic selective membrane comprising the selective silica ceramic supported by the porous membrane substrate;
• wherein the ceramic precursor sol comprises an alkaline silicate solution;
• wherein the porous membrane substrate has a plurality of pores 10 nm or greater in diameter;
• further comprising a step of impregnating an edge portion of the porous membrane substrate with a compressible polymer prior to the step of applying the ceramic precursor sol to the porous membrane substrate;
• wherein gelling the ceramic precursor sol comprises chemical gelation
• wherein gelling the ceramic precursor sol comprises exposing to a temperature in the range of 20° C. to 100° C.;
• wherein the ceramic selective membrane comprises pores in the size range of 0.1 nm to 10 nm in diameter;
• wherein the ceramic selective membrane has a thickness in the range of 0.1 mm to 1 mm;
• and
• wherein the ceramic precursor sol further comprises an additive selected from the group consisting of a selectivity additive configured to increase ion transport properties of the ceramic selective membrane, a durability additive configured to improve durability of the ceramic selective membrane, and a catalyst additive configured to add catalytic properties to the ceramic selective membrane.