Photoelectrocatalytic Utilization of CO₂ : A Big Show of Si-based Photoelectrodes

CO₂ is a greenhouse gas that contributes to environmental deterioration; however, it can also be utilized as an abundant C1 resource for the production of valuable chemicals. Solar-driven photoelectrocatalytic (PEC) CO₂ utilization represents an advanced technology for the resourcing of CO₂ . The key to achieving PEC CO₂ utilization lies in high-performance semiconductor photoelectrodes. Si-based photoelectrodes have attracted increasing attention in the field of PEC CO₂ utilization due to their suitable band gap (1.1 eV), high carrier mobility, low cost, and abundance on Earth. There are two pathways to PEC CO₂ utilization using Si-based photoelectrodes: direct reduction of CO₂ into small molecule fuels and chemicals, and fixation of CO₂ with organic substrates to generate high-value chemicals. The efficiency and product selectivity of PEC CO₂ utilization depends on the structures of the photoelectrodes as well as the composition, morphology, and size of the catalysts. In recent years, significant and influential progress has been made in utilizing Si-based photoelectrodes for PEC CO₂ utilization. This review summarizes the latest research achievements in Si-based PEC CO₂ utilization, with a particular emphasis on the mechanistic understanding of CO₂ reduction and fixation, which will inspire future developments in this field.