Three-dimensional palm frondlike Co3O4@NiO/graphitic carbon composite for photocatalytic CO2 reduction

Three-dimensional (3D) palm frondlike S-scheme heterojunction based the Co3O4@NiO/graphitic carbon (Co@Ni/GC) composites were fabricated via a simple polymer heat treatment method as photocatalysts for CO2 reduction reactions (CO2RR). The optimal Co@Ni/GC-700 catalyst exhibits excellent performance and stability for photocatalytic CO2RR. Under visible light irradiation, the maximum yields for CH4 and CO are 9.79 μmol g−1 h−1 and 4.89 μmol g−1 h−1, respectively. The photocatalytic CO2RR activity of the Co@Ni/GC catalysts is superior to Co3O4 or NiO, which could be attributed to the direct S-scheme heterojunction induced by the interfacial electric field (EF) and the improved CO2 adsorption capacity in Co@Ni/GC. DFT calculations revealed that an interfacial EF is formed due to the electron transfer from NiO to Co3O4 in the Co@Ni/GC catalysts. This work provides new insights for designing advanced S-scheme heterojunction photocatalytic CO2RR catalysts with ideal performance. [Display omitted] •The layered porous structure of the 3D palm frond-like catalyst improve the light harvesting.•The S-scheme charge transfer mechanism can effectively inhibit carrier recombination.•The good conductivity of GCs can reduce the transfer resistance of e− at the interfaces.•Under UV–visible light irradiation, the maximum CH4 yield of the Co@Ni/GC-700 catalyst is 9.79 μmol/(g·h).