“…The concentration of developing elements in solution influences the nucleation and crystal formation, affecting the activity. 113 Co-catalytic systems such as copper oxide and zinc oxide nanowires with a core–shell structure, 114 copper/copper oxide heterojunctions with nickel decoration, Fe 2 O 3 nanorod/MgFe 2 O 4 heterojunctions with three-dimensional (3D) cobalt branching, 115 and TiO 2 anatase combined with copper oxide, have been developed and studied extensively ( Fig. 6a ).…”