Ultra-deep photocatalytic desulfurization of dibenzothiophene over hollow Core-shell N-doped graphene nanospheres anchored bimetallic single atoms under visible light

HCS-NG-Ni/Cu nanospheres composed of the 100-120 nm hollow core-shell N-doped graphene with lattice spacing d = 0.25 nm were prepared by a facile method and their surfaces were decorated with d = 0.14 nm Ni and d = 0.12 nm Cu single atoms. Characterization of HAADF-STEM, XPS, Raman, and photoelectron-chemi-cal showed the morphology of Ni/Cu was a single atomic state on the hollow core-shell N-doped graphene, which could effectively inhibit the photoelectron-hole pair recombination leading to improve the efficiency of photo catalytic desulfurization. The influence of metal loading, Ni:Cu ratios, time, catalyst amount, and different catalysts on the removal of DBT were investigated. Results indicated the hollow core-shell N-doped graphene decorated with Ni/Cu had higher photocatalytic removal ratios (> 99.1%) than the others under the mild conditions and had a high activity even after 10 cycles because of the synergism of single Ni/Cu atoms and the hollow core-shell N-doping-graphene under visible light. The energy barrier and the removal rate constant of DBT were 78 kJ/mol and 3.79*10(-2), respectively, and the photocatalytic mechanism was assumed. Researches provided not only a high-efficiency desulfurization catalyst to produce clean fuel, but also a new idea on designing bimetallic single-atom catalysts.

Automated summary

In this study, HCS-NG-Ni/Cu nanospheres with single Ni/Cu atoms decorated on the surface of hollow core-shell N-doped graphene were prepared. The results showed that the Ni/Cu-decorated hollow core-shell N-doped graphene exhibited high photocatalytic desulfurization efficiency and maintained high activity under visible light.