This review summarizes the recent advances in light driven catalytic H₂evolution and CO₂reduction systems towards the production of solar fuels, utilizing porphyrin or phthalocyanine derivatives.

Solar energy is undoubtedly one of the most exploitable energy sources providing a potential solution to address the environmental issues deriving from the excessive use of fossil fuels. Over the last few years p-type dye sensitized solar cells (p-DSCs) have attracted substantial attention, since their incorporation with n-type DSCs could potentially lead to more efficient tandem cell pn-DSCs. Moreover, new research has been devoted to dye-sensitized photoelectrochemical cells (DSPECs), in which solar energy is utilized to generate hydrogen via water splitting. This article provides a summary of recent sensitizers employed in dye-sensitized NiO photocathodes for DSC and DSPEC, discussing approaches to enhance their overall performance. In particular, we intend to provide new directions through molecular design of new dyes and stimulate additional research development in the fields of DSCs and DSPECs.

A combination of noble-metal free components, a water soluble porphyrin photosensitizer zinc meso-tetrakis(1-methylpyridinium-4-yl)porphyrin chloride [ZnTMPyP⁴⁺]Cl₄ (1) with cobaloxime complex [Co^III(dmgH)₂(py)Cl] (2) as a catalyst, creates an efficient system for photochemical hydrogen production acting under visible light with 280 TONs. This is the first example of a water soluble porphyrin acting as a photosensitizer for cobaloxime catalysed H₂ production.