An example approach and structure for providing a chemical sensor, having an electrode that may receive a fluid that is passed on towards a dielectric between the electrode and one or more other electrodes. A capacitance between the electrodes may be changed by the dielectric which is affected by a parameter of the fluid. Measuring a change of the capacitance may indicate a magnitude of the parameter. The electrode receiving the fluid may have one or more layers of metal particles that by design of the particles and their arrangement can result in determined pore sizes and routes through the electrode for a controllable porosity of the electrode.