Functioning devices for solar to fuel conversion

This paper provides a perspective on the technologies capable of converting solar energy, CO2 and H2O into an easy to use fuel. The paper addresses bio-based approaches, but mainly focuses on (i) the combination of photovoltaic (PV) devices and electrocatalysis, (ii) single unit operation by photocatalytic conversion, and (iii) solar thermal conversion. Each option is described in a general manner, including a brief evaluation of the advantages and disadvantages. Also suggestions for future research endeavours are given. Based on the used literature data, for electrocatalytic and photocatalytic technologies, dramatic improvements should be made in material optimization, as well as reactor design and operation. Large efficiency gains are necessary to enable use of these technologies in practice. Solar thermal conversion is more mature, and requires specific optimization in processing, as will be discussed.