Constructing S-scheme Co3O4-C3N4 catalyst with superior photoelectrocatalytic efficiency for water purification

Choosing satisfactory semiconductor materials as photoanode to promote the production of intermediate active species (hydroxyl radical and superoxide radicals) is a challenging problem for the decomposition of refractory organic from wastewater. Herein, Co3O4-C3N4 heterogeneous photoanode (a two-dimensional ɣ-C3N4 is coated on one-dimensional Co3O4 nanowire) was fabricated using a simple impregnation-heating treatment process. By optimizing the amount of ɣ-C3N4, the Co3O4-C3N4-10 catalyst has been systematically investigated by experimental and theoretical aspects. The Co3O4-C3N4-10 catalyst exhibits excellent PEC activity for degrading reactive brilliant blue KN-R with a degradation rate of ∼91.3% owing to its low Tafel slope, numerous active sites, low charge transfer resistance, and PEC synergistic effects. The carrier transfer mechanism of S-scheme for Co3O4-C3N4 heterostructure was proposed because hydroxyl radical (•OH) and superoxide anion radical (•O2−) are the dominant active species, endowing Co3O4-C3N4-10 as promising catalysts for practical application. This work enlightens the rational design of advanced photoanode for water purification and environmental remediation.