The Sun's spectrum peaks at about . From the post "Photons With Kinetic Energy?" dated 5 Dec 2017,
The best material to absorb this frequency is,
where is in and is the atomic number or the sum of all atomic numbers in a molecule.
At this high value, water () cannot act as a good absorber because of its low density
Titanium and density , on the other hand,
comes close to this value, so a suspension of or (, density (Rutile) and (Anatase)) in a suitable fluid such that its adjusted density is,
will absorb at the Sun's peak frequency.
For the case of , by weight, a portion,
of the suspension is and the rest by weight is fluid. Given the high density of , it might still be possible for a good suspension that flow with low viscosity.
For the case of , Anatase, in a suspension of,
portion by weight. A light weight fluid will hold this material in suspension that flows well.
It is best that the suspension flows to prevent settlements.
But what is captured from the Sun's spectrum?