Ni-Co Bimetallic Hydroxide Nanosheet Arrays Anchored on Graphene for Adsorption-Induced Enhanced Photocatalytic CO 2 Reduction.

Photocatalytic CO 2 reduction can be implemented to use CO 2 , a greenhouse gas, as a resource in an energy-saving and environmentally friendly way, in which suitable catalytic materials are required to achieve high-efficiency catalysis. Insufficient accessible active sites on the catalyst surface and inhibited electron transfer severely limit the photocatalytic performance. Therefore, porous aerogels are constructed from composites comprising different ratios of Ni-Co bimetallic hydroxide (Ni x Co y ) grown on reduced graphene oxide (GR) into a hierarchical nanosheet-array structure using a facile in situ growth method. Detailed characterization shows that this structure exposes numerous active sites for enhanced adsorption-induced photocatalytic CO 2 reduction. Moreover, under the synergistic effect of Ni-Co bimetallic hydroxide, the CO 2 adsorption capacity as well as charge-carrier separation and transfer are excellent. As a result, the Ni 7 Co 3 -GR catalyst exhibits highly improved catalytic performance when compared with recently reported values, with a high CO release rate of 941.5 µmol h -1  g -1 and a selectivity of 96.3% during the photocatalytic reduction of CO 2 . This work demonstrates a new strategy for designing nanocomposites with abundant active sites structures.