Motivated surface reaction thermodynamics on the bismuth oxyhalides with lattice strain for enhanced photocatalytic NO oxidation

Understanding and establishing a specific relationship between modified structures and photocatalytic reaction process has a profound significance for designing catalysts with preferable activity. In this study, we have favorably synthesized the bismuth oxyhalides (BiOClxBr1-x, 0 <= x <= 1) photocatalysts by utilizing the ethylene glycol assisted solvothermal method and the calcination procedure for photocatalytic nitric oxide oxidation. By regulating the halogen proportion in anions layer, the lattice strain has been induced in the structure, specifically the tensile strain in c axis. By virtue of in situ DRIFTS and DFT calculation, we found that the optimized surface reaction thermodynamic process should be the main factors response for prominent enhanced photocatalytic activity, rather than the light absorption and separation of carriers. The bismuth oxyhalides with Cl/Br ratios of 3:1 (BiOClxBr1-x-3:1) possess the lowest thermodynamic energy barrier for photocatalytic nitric oxide oxidation reaction, whilst both associative and dissociative reaction process exist in the initial elementary reaction about oxygen reduction. Finally, we develop a feasible strategy to depress thermodynamic energy barriers via tuning the ratio of halogen in anions layer and bringing the lattice strain, as well build relationship between the adjusted structures and surface reaction process.

Automated summary

By adjusting the halogen ratio in bismuth oxyhalides, the thermodynamic energy barrier for photocatalytic nitric oxide oxidation can be lowered, while establishing a relationship between lattice strain and surface reaction process.