Production method for photo-electrocatalytic electrodes from industrial pigment powders

Photo-electrocatalytic reactions assume an increasingly important role in water splitting or reduction of CO2 towards higher hydrocarbons. Fabrication of electrodes, used for this purpose, often requires laborious and costly synthesis steps. With a recent development, however, pre-fabricated industrial pigments can be employed with much less efforts. After modification of the size of the pigment particles and a suitable coating procedure, essential electronic properties turn out to be improved, and electrode manufacturing on a large scale becomes feasible.

The invention presented here describes an electrode with a catalytic layer of semiconductor particles of homogeneous size distribution, surrounded by an amorphous semiconductor layer (Matrix). This arrangement facilitates an improved electric conductivity and increased light conversion efficiency. Furthermore the invention comprises the production method for manufacturing of the electrode and the use of cost-efficient semiconductor materials: In a suspension of the particles, a brief voltage pulse is applied for selective deposition of small-sized particles onto a substrate. Remaining particles in the suspension are then subjected to partial chemical dissolution until they reach the desired (small) size and are subsequently deposited. Electrodes manufactured by this recurrent procedure demonstrate photocurrent densities many times higher than those fabricated from unmodified pigment powders.