Sn‐Coupled p‐Si Nanowire Arrays for Solar Formate Production from CO₂

Vertically aligned, free-standing p-Si nanowire arrays of varying lengths are grown on p-Si wafers and coupled with Sn nanoparticles for solar CO2 conversion. These heterojunction wire/Sn arrays increase the production of formate dramatically, by more than 10 and 5 times compared to planar p-Si and wire arrays, respectively, with Faradaic efficiencies of ≈40% in a single cell and 88% in a H-type cell.