Recent progress in artificial photosynthesis: CO2 photoreduction to valuable chemicals in a heterogeneous system

► Multiple-hole oxidation process is the bottleneck for solar fuel synthesis. ► Formation of higher carbon chain is usually very difficult caused by weakly bonded CO. ► A new strategy couples the photoreduction of CO2 with water photolysis. ► Junction photocatalyst system performs much better than single materials. ► Solid-state mediator is proven effective as alternative liquid mediators.