Interspersing CdS nanodots into iodine vacancy-rich BiOI sphere for photocatalytic lignin valorization

Flower-like BiOI was decorated by CdS nanodots and followed by the introduction of iodine vacancies (V_I) for photocatalytic sodium lignosulfonate (SLS) valorization under visible light. The iodine vacancies could adjust the band configuration, strengthen the light absorption and act as electron traps, while the intimate contact between BiOI and CdS nanodots provides a high-speed channel for charge transfer. As a consequence, the photocatalytic performance of SLS conversion into value-added vanillin was greatly improved over CdS/BiOI-V_I compared with those of CdS, BiOI and CdS/BiOI. The highest yield of vanillin is 10.95 mg/g_SLS over CdS/BiOI-V_I, about 5, 8.7, 1.3 times those of CdS, BiOI, CdS/BiOI, respectively, and exceeding most related photocatalysts reported elsewhere. More significantly, as to the lignin from Masson pine and alkali lignin, the corresponding vanillin yield can reach 7.04 and 6.54 mg/g_lignin, respectively, under the same condition, which suggests the great potential and universality for photocatalytic lignin valorization over such CdS/BiOI-V_I heterostructure.