Photocatalytic reduction of CO2 provides an opportunity to reach carbon neutrality, by which CO2 emissions from fuel consumption can be converted back to fuels. The challenge is to explore materials with high charge separation efficiency and effective CO2 adsorption capacity to boost the photoreduction of CO2. Here we report that a 2D heterostructure comprised of Co3O4/2D g-C3N4 (COCN) can provide enhanced photocatalytic reduction of CO2 to CO, yielding a CO production rate of 419 mu mol g(-1) h(-1) with a selectivity of 89.4%, which is 13.5 and 2.6 times higher than that of pure 2D g-C3N4 and Co3O4. The enhanced photocatalytic performance arises from (i) enhanced light absorption ability and charge separation efficiency originating from the unique 2D heterostructure connected through specifically exposed facet interfaces and (ii) favorable CO2 adsorption capacity. The study may provide insight for the establishment of a heterostructure-based photocatalytic system toward CO2 reduction.