Abstract:
An all-inorganic nanocomposite coating of titania has been found to revamp the reduction in efficiency of
solar panels arising due to atmospheric pollution. A multifunctional, photoactive and hydrophobic titania–
silica–lanthanum phosphate (TSL) nanocomposite having excellent anatase thermal stability is reported for
the first time as alternative coatings on solar panel covers for maintaining the energy efficiency of panels
over a period of time under outdoor conditions. The precursor source of silica has been found to
significantly influence the photoactivity of titania in the nanocomposite under investigation. Polymeric
silica is derived from the tetraethylorthosilicate precursor while particulate silica is aqueous colloidal
silica. The enhanced photoactivity of the particulate titania–silica composition is attributed to the
presence of phase pure anatase having an optimum crystallite size and surface area, achieved in the
presence of silica. Lanthanum phosphate which has low water wettability is further influenced by
particulate silica in providing better non-wetting behavior to the TSL nanocomposite. The presence of
particulate silica in the TSL composite is superior to that containing polymeric silica in terms of
crystallinity, photoactivity and low wettability. Thus, functional titania coatings possessing synergistic
properties of the constituents can be designed from a less expensive and effective silica precursor. The
all-inorganic system investigated in the present work is environmentally friendly and is stable over a wide
range of temperatures. The feasibility of large-scale preparation and application of the particulate TSL
nanocomposite coatings on solar panels under outdoor exposure has been demonstrated. The present
novel approach for the development of aqueous-derived, self-cleaning, energy conserving coatings will
lead to the energy revamping of solar panels and may have large-scale industrial applications.
