Direct generation of nitrogen-centered radicals via non-covalent interaction between Cu complexes and BiVO4 photoanodes

Semiconductor-based photoelectrochemistry commonly relies on efficient interactions between semiconductor surfaces and adsorbates for promoting charge transfer and efficiently activating inert bonds. But at the repulsive interfaces (e.g., between like-charged substrates and electrodes), such interactions cannot be achieved. Contrary to this paradigm, we find that the van der Waals interaction between a series of N-coordinated Cu complex cations and BiVO4 photoanodes results in a high photovoltage of 0.53 V and charge transfer efficiency of 96%, along with the photocurrent density approaching the theoretical limit of BiVO4. This non-covalent interaction enables the universal generation of nitrogen-centered radicals from directly cleaving native N−H bonds and generates N–N coupling products with a Faradaic efficiency exceeding 96%. Its practical application is further demonstrated in an amplified photoelectrochemical reactor, generating a photocurrent of 409 mA and a yield rate of 6069 μmol h−1 for hydrazine production, which is competitive with most reported N−N coupling methods. Photoelectrocatalysis often relies on covalent electrode-reactant interactions. Here, the authors report that non-covalent interactions at Cu complexes/BiVO4 interfaces enable rapid charge transfer, directly generating N-centered radicals from inert N−H bonds for scalable hydrazine synthesis.