“…In response to the limitations of previous materials, bifunctional Co 3 O 4 /G-C 3 N 4 heterostructures have emerged as an exciting avenue for advancing tandem photoelectrochemical water splitting. , Co 3 O 4 , a transition-metal oxide, is known for its high electrical conductivity and chemical stability, making it a suitable candidate for catalyzing the water oxidation reaction. , G-C 3 N 4 , on the other hand, is a metal-free and eco-friendly semiconductor with excellent light absorption properties and efficient electron–hole separation. , The combination of these materials in heterostructures facilitates efficient charge separation and transfer, minimizing electron–hole recombination and optimizing overall photocatalytic performance. , …”