Enhanced C-C coupling selectivity by sulfur vacancy for photocatalytic pyridinemethanol conversion with simultaneous H2 evolution

The synergistic coupling of photocatalytic C C bond construction and H 2 evolution presents a promising strategy for concurrent organic synthesis and sustainable H 2 evolution. Nevertheless, precisely regulating the reaction pathways to enhance the selectivity of target products remains a challenging. Here, the Sv-CdS/TiO 2 Ni 2 P photocatalyst containing sulfur vacancies was synthesized via calcination, achieving highly selective conversion of 4-pyridinemethanol into the C C coupling product 1,2-di-(4-pyridyl)-1,2-ethanediol under visible-light irradiation, with a selectivity of 96.59 %. In comparison, the M-CdS/TiO 2 Ni 2 P photocatalyst prepared by mechanical mixing exhibits superior H 2 evolution activity of 6.48 mmol·g -1 ·h -1 . Mechanism studies reveal that 4-pyridinemethanol interacts with the Sv-CdS/TiO 2 Ni 2 P photocatalyst through the N atom, which preferentially activates the sp 3 C H bond of 4-pyridinemethanol to generate •CH(OH)C 5 H 4 N radical for further C C coupling reaction. This work not only highlights the selective regulation of the 4-pyridinemethanol C C coupling pathway by sulfur vacancies engineering, but also provides new insights for achieving efficient photocatalytic organic synthesis and green H 2 evolution.