Global warming and adverse climate change, which have been intensified by a strident increase in carbon dioxide (CO2) emissions, have necessitated the development of alternative techniques to reduce the disproportionate concentration of CO2 in the atmosphere. The photoelectrochemical reduction of CO2 is a technique of lowering the energy required to convert greenhouse gases into useful end products. Herein, we have manufactured an innovative, cost-effective silver (Ag) decorated anatase TiO2 (TOAgx; ‘x’ stands for different concentration of Ag) nanoparticles which created on the 3D nanoporous structured surface of a thin titanium foil (Ti-foil) by the assist of chemical treatment with hydrogen peroxide (H2O2) and different concentrations (1, 5, 10, 20 mM) of silver nitrate (AgNO3) solution and followed by calcination at 500 ℃. As-prepared samples were analyzed by several characterization techniques such as XRD, XPS, TEM and Raman spectroscopy. Among various samples (TO, TO-Ag1, TOAg5, TO-Ag20), the TO-Ag10 sample were exposed a supreme photocurrent density of 83.2 µA/cm-2 (86.1% higher than TO sample which is untreated with AgNO3 solution). Because of its high photocurrent density, the sample TO-Ag10 were selected as the electrode material for photoelectrochemical CO2 reduction reaction and a lowest reduction onset potential (-1.018 V) was observed on linear sweep voltammetry analysis in the presence of light with Ag/AgCl reference electrode. 1H NMR analysis of the product solution exposed the production of formic acid as a single product of CO2 reduction reaction after the chronoamperometric electrolysis were carried out more than 6 h. The maximum faradaic efficiency (73%) and formic acid yield (193 µmol cm-2 h-1) were found at an applied potential of -1.2 V (vs. Ag/AgCl reference electrode) for TO-Ag10 photocathode.