Integration of organometallic complexes with semiconductors and other nanomaterials for photocatalytic H2 production

The development of energy-efficient, cost-effective and durable photocatalytic systems for water splitting is one of the scientific problems that must be solved before the successful transformation from a fossil fuel-based economy to a solar fuel-based economy can be realized. Conventional photocatalytic systems are generally divided into heterogeneous systems of semiconductors, usually modified by noble metals or inorganic cocatalysts, and homogeneous systems comprised of molecular catalysts and organic or organometallic chromophores. In recent years, some hybrid photocatalytic systems were reported to be highly active and robust for photoinduced H-2 production, indicating that the integration of semiconducting materials with proper molecular catalysts is an effective strategy for constructing efficient photocatalytic systems for water splitting. This review will focus on hybrid photocatalytic systems, developed in the past three years, in which proton reduction molecular catalysts incorporate either semiconducting materials or inorganic, metal-organic, and other polymeric nanomaterials for photochemical H-2 generation from water. In the last section of the review, problems existing in the current hybrid photocatalytic systems are discussed; future challenges and developments are envisaged. (C) 2014 Elsevier B.V. All rights reserved.