Carbon dots-embedded amorphous nickel oxide for highly enhanced photocatalytic redox performance

Amorphous materials reveal promising prospects in photocatalysis for the abundant active sites and tunable electronic configuration due to the lattice flexibility. However, the intrinsic lattice distortion could also cause the self-trapping effect and results in the recombination of photogenerated carriers. This disadvantage could be modified by the small size of amorphous domains for reducing charge migration distance. For this purpose, carbon dots (CDs) are introduced as the heterogeneous nucleus to regulate the configuration and composition of the amorphous nickel oxides for efficient utilization of photocarriers in catalytic reactions. The resultant nanocomposites a-NiO_x/CDs show the densely distributed CDs embedded in the amorphous nickel oxide with dual valences of Ni²⁺ and Ni³⁺, and they reveal superior activities in photocatalytic oxidation and reduction compared with the single amorphous nickel oxide. The extraordinary photocatalytic performance is attributed to the synergetic function of their excellent separation efficiency of photoinduced charges and the cyclic conversion between Ni²⁺ and Ni³⁺ in the defects. This work provides inspiration for the modification and photocatalytic application of the amorphous materials.