Enhanced mass transfer with amphiphilic CoOx/biochar for photocatalytic CO2 conversion

Abstract

Special wetting ability of catalyst plays an important role in photocatalytic CO2 conversion. Herein, we find that amphiphilic CoOx/biochar (CDB) with a synergistic effect is beneficial for the photocatalytic CO2 conversion. Contact angle experiments display that the amphiphilic performance of CDB-3 (amphiphilic CoOx/biochar with 3.0% wt. cobalt) is due to the formed micro-/nanostructures stemmed from loofa sponge and CoOx. The contact angle of molecular CO2 on CDB-3 is 69.6° in the reaction system. CO2-temperature programmed desorption and polarization curves demonstrate that amphiphilic surface increases the CO2 mass transfer. Photoluminescence (PL) spectra shows that CDB-3 has an optimized carrier migration efficiency. Therefore, CDB-3 exhibits an efficient photocatalytic CO2 conversion with a turnover frequency (TOF) of 0.29 s−1 and CO production rate of 48.3 umol/h, which is a 3.4-fold than pure CDB.