Graphitic Carbon Nitride Structures on Carbon Cloth Containing Ultra- and Nano-Dispersed NiO for Photoactivated Oxygen Evolution

The development of low-cost and high-efficiency oxygen evolution reaction (OER) photoelectrocatalysts is a key requirement for H₂ generation via solar-assisted water splitting. In this study, we report on an amenable fabrication route to carbon cloth-supported graphitic carbon nitride (gCN) nanoarchitectures, featuring a modular dispersion of NiO as co-catalyst. The synergistic interaction between gCN and NiO, along with the tailoring of their size and spatial distribution, yield very attractive OER performances and durability in freshwater splitting, of great significance for practical end-uses. The potential of gCN electrocatalysts containing ultra-dispersed, i. e. "quasi-atomic" NiO, exhibiting a higher activity than the ones containing nickel oxide nanoaggregates, is further highlighted by their activity even in real seawater. This work suggests that efficient OER catalysts can be designed through the construction of optimized interfaces between transition metal oxides and carbon nitride, yielding inexpensive and promising noble metal-free systems for real-world applications.