Advances in Design and Scale‐Up of Solar Fuel Systems

Production of solar fuels through CO 2 reduction with water and sunlight is a key process towards a net-zero future. Significant progress has been made in the development of novel materials and catalysts. However, solar fuel technologies still face obstacles towards scale-up. This chapter reviews the current state-of-the-art technologies developed and the effect of operating conditions on system performance. The most promising technologies are photocatalytic (PC), photovoltaic powered electrochemical (PV+EC) and photoelectrochemical (PEC) solar fuel production systems. PC systems have simple designs and are used where the driving force of the reduction reaction is only dependent on the solar energy/incident light. Electrochemical (EC) systems utilize catalytic conversion of CO 2 to other chemicals and fuels in an electrolytic cell powered by electrical energy. The integration of an electrochemical reactor with a light source and a photocatalyst obtains a photoelectrochemical (PEC) reactor. The three PEC system configurations used are photocathode – anode, cathode – photoanode and photocathode – photoanode systems. Of the various reactors, the three main operating conditions, i.e., irradiation, temperature, and pressure of the system, were studied to understand the effect they have on the reactor performances. Finally, key considerations were highlighted that need to be considered when designing and scaling up solar fuel systems.