Oxygen-exfoliated cobalt-doped C3N4 for superior Fenton-like catalysis: The accessible metal exposure and synergistic pollutant adsorption from three-dimensional layered configuration

Solid catalyst plays the governing role in the heterogeneous Fenton-like catalysis for water purification. In this work, the Co(II)-doped C3N4 (Co/C3N4) was prepared and further thermally exfoliated in different atmosphere for the three-dimensional layered configuration. The morphological and structural properties as well as surface chemistry of Co/C3N4 before and after thermal exfoliation were elucidated in comparison. The oxygen-exfoliated Co/C3N4 (O-Co/C3N4) exhibited accessible metal exposure and synergistic pollutant adsorption stemmed from three-dimensional layered configuration with ordered porous configuration, oriented lamellar structure and increased surface area. Moreover, an excellent Fenton-like reactivity and stability was measured for PMS activation and pollutant degradation, and the comparative performance before and after oxygen exfoliation as well as with typical metal-based catalysts were investigated in details. The impacts of testing conditions and water matrices were elucidated to estimate environmental potential. Based on radical identifying and inhibiting tests and electrochemical measurements, the non-radical reaction pathway from mediated electron transfer (MET) played the key role with much reduced matrix effects and satisfactory catalytic selectivity. This work provides a new chance to save transition-metal consumption and refine Fenton-like reactivity in C3N4-based catalysts for superior environmental remediation.