Morphology controlled synthesis of 2D heterostructure Ag/WO₃ nanocomposites for enhanced photoelectrochemical CO₂ reduction performance

Supporting nanomaterials having strong metal-support interaction is the key to an efficient catalyst. The present paper describes a morphology-controlled synthesis of silver (Ag) nanoparticles supported on nanostructured tungsten oxide (WO₃) for selective photoelectrocatalytic carbon dioxide reduction reactions (CO₂RR) under visible light irradiation. Highly dispersed Ag on WO₃ nanorod was synthesized by a one-pot preparation method in the presence of cetyltrimethylammonium bromide (CTAB). The synthesis strategy remained intact and reproduced by varying loading of Ag, which was further confirmed by various characterization techniques like XRD, SEM, TEM, STEM elemental mapping, Raman, XPS, FT-IR, and BET analysis. The morphological growth of the WO₃ nanorod (NR) and the related mechanism was studied and discussed in the paper. 1.5 wt % Ag showed optimum loading for high dispersion over WO₃-NR and efficient CO₂RR with high current density (0.4 mA cm⁻²), towards the desired selective product formation (formic acid). The efficiency of the catalyst was further correlated with cluster vacancies on the interface of Ag particle and WO₃ nanorod by positron doppler broadening (DB) spectroscopy.