In the field of recycling CO 2 , the photocatalytic CO 2 reduction reaction (CO 2 RR) is a typical example, and researchers have designed a variety of photocatalysts to improve the conversion rate of CO 2 over the years. In this paper, two metal−oxygen clusters are designed and formulated as [Co 3 Zn(OH) 6 (SO 4 )]• 4H 2 O (1) and [Ni 3 Zn(OH) 6 (SO 4 )]•4H 2 O (2). As for compound 1, the main structure is composed of {CoO 6 } octahedra connected by edge-sharing to form a twodimensional layer, on which {ZnO 4 } and {SO 4 } tetrahedra are supported. More interestingly, compound 1 has outstanding photocatalytic activity, which is mainly attributed to the open-framework structure and the cobalt ions as active sites. Upon catalysis for eight hours, its maximum CO generation rate is 9982.13 μmol g −1 h −1 , with a selectivity of 81.8%. Additionally, compound 1 takes on weak antiferromagnetic coupling due to Co(II) ions.