Ultrathin Phosphate-Modulated Co Phthalocyanine/g-CN Heterojunction Photocatalysts with Single Co-N (II) Sites for Efficient O Activation.

Realization of solar-driven aerobic organic transformation under atmospheric pressure raises the great challenge for efficiently activating O by tailored photocatalysts. Guided by theoretical calculation, phosphate groups are used to induce the construction of ultrathin Co phthalocyanine/g-CN heterojunctions (CoPc/P-CN, ≈4 nm) via strengthened H-bonding interfacial connection, achieving an unprecedented 14-time photoactivity improvement for UV-vis aerobic 2,4-dichlorophenol degradation compared to bulk CN by promoted activation of O. It is validated that more O radicals are produced through the improved photoreduction of O by accelerated photoelectron transfer from CN to the ligand of CoPc and then to the abundant single Co-N (II) catalytic sites, as endowed by the matched dimension, intimate interface even at the molecular level, and high CoPc dispersion of resulted heterojunctions. Interestingly, CoPc/P-CN also exhibits outstanding photoactivities in the aerobic oxidation of aromatic alcohols. This work showcases a feasible route to realize efficient photocatalytic O activation by exploiting the potential of ultrathin metal phthalocyanine (MPc) assemblies with abundant single-atom sites. More importantly, a universal facile strategy of H-bonding-dominating construction of MPc-involved heterojunctions is successfully established.