<p>The photoreduction of CO₂ into sustainable and green solar fuels is an intriguing way to simultaneously address environmental disasters and energy shortage. Bismuth tungstate (Bi₂WO₆) samples were synthesized in a single phase using ascorbic acid for photocatalytic CO₂ reduction upon exposure to UV–vis irradiation. The best performing Bi₂WO₆ sample synthesized with 1.0&#xa0;g ascorbic acid (BW1) showed a significant CO production rate which was almost 3.8 times greater than pristine Bi₂WO₆ (BW0). The activity of BW1 was improved by the exposed pore area (4.89 m²/g) which has increased by 53% due to surface modification, decreasing the reaction energy barrier for protonating activated CO₂ to its intermediates with the help of H₂O molecules. The photocatalytic CO₂ reduction mechanism of the BW1 photocatalyst was investigated based on in situ diffuse reflection infrared spectroscopy results. The anticipated CO₂ methanation routes were CO₂* → COOH* → CO and CO₂ → HCO₃^– → CH₄. The BW1 sample exhibited a CO₂ selectivity of 86% and the CO and CH₄ formation rate of 70.88&#xa0;µmol&#xa0;g⁻¹&#xa0;h⁻¹ and 27.87&#xa0;µmol&#xa0;g⁻¹&#xa0;h⁻¹, respectively, owing to the modification of the BW1 pore surface area by the ascorbic acid. The study demonstrated that Bi₂WO₆ photocatalyst with diverse morphologies effectively enhances physisorption and chemisorption processes on catalytic surfaces, achieving high photocatalytic efficiency.</p>