Fig. 3

a The conversion of ozone using p- and n-type Si NWs as catalysts; b EPR detection of p- and n-type Si NWs; and c Schematic comparison of p- and n-type Si NWs. P-type Si is lack of electrons and has positively charged holes, and thus, the release of electron and desorption of O₂²⁻ is easier than the case of n-type Si