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Crystallites of Cu-coordinated poly(triazine imide) were synthesized by flux methods and deposited from particle suspensions onto electrodes, yielding sizable current densities for the electrocatalytic reduction of CO ₂ .

We report the development of a hybrid catalyst consisting of carbon nitride (CN_x) and cobalt phthalocyanine tetracarboxylic acid (CoPc-COOH), which converts CO₂ to CO with high reaction rate (1067 μmol/g·h) and high selectivity (over 98%), under simulated solar irradiation. The carboxylic acid substituents on the phthalocyanine ligands play a critical role as they bind to the amine groups of CN_x to enable nearly ideal monolayer coverage of the molecular co-catalyst on the semiconductor surface and promote catalytic activity from the molecular complex. Specifically, the CN_x/CoPc-COOH hybrid material achieves a reaction rate 16 times higher than a CN_x material containing unsubstitutedmore » CoPc molecules. We further show that activation and deactivation of the CN_x/CoPc-COOH composite, which are associated with the reduction and decomposition of CoPc-COOH, respectively, both proceed at a nearly constant rate regardless of the CO₂ reduction reaction rate. Here, the decoupling of charge carrier injection and CO₂ reduction catalysis has important mechanistic implications for future performance optimization and materials design of photocatalysts for CO₂ reduction.« less

The in-depth understanding of the reported photoelectrochemical properties of the layered carbon nitride, poly(triazine imide)/LiCl (PTI/LiCl), has been limited by the apparent disorder of the Li/H atoms within its framework. To understand and resolve the current structural ambiguities, an optimized one-step flux synthesis (470 °C, 36 h, LiCl/KCl flux) was used to prepare PTI/LiCl and deuterated-PTI/LiCl in high purity. Its structure was characterized by a combination of neutron/X-ray diffraction and transmission electron microscopy. The range of possible Li/H atomic configurations was enumerated for the first time and, combined with total energy calculations, reveals a more complex energetic landscape than previouslymore » considered. Experimental data were fitted against all possible structural models, exhibiting the most consistency with a new orthorhombic model (Sp. Grp. Ama2) that also has the lowest total energy. In addition, a new Cu(I)-containing PTI (PTI/CuCl) was prepared with the more strongly scattering Cu(I) cations in place of Li, and most closely matching with the partially-disorder structure in Cmc2₁. Thus, a complex configurational landscape of PTI is revealed to consist of a number of ordered crystalline structures that are new potential synthetic targets, such as with the use of metal-exchange reactions.« less