Mixed oxide materials have been intensely investigated in catalysis. In recent years, photoactive species have been deposited on high surface area supports and investigated for a variety of applications that include Dye Sensitized Solar Cells (DSSC), photocatalytic and photoelectrochemical splitting of water, and photocatalytic degradation of organics. Basic materials like MgO are attractive as supports for the above mentioned applications, since they can be synthesized conveniently with relatively large surface areas and porosities. The wide band gap (>7 eV) and hence the insulating nature of MgO also lends itself to interesting uses in several applications involving solar energy conversion. The presence of low amounts of MgO has been found to be beneficial for DSSC, photo-electrochemical splitting of water, and photocatalytic degradation of dye molecules and will be discussed in-depth in this review. (C) 2017 Elsevier B.V. All rights reserved.