Carbon dioxide (CO₂) photoreduction is a complex process and, despite significant efforts in photocatalyst development, an investigation of the influence of process parameters on photoreduction is still necessary. In this work, a Bi₂WO₆ photocatalyst was used for the photocatalytic reduction of CO₂ in a continuous-flow differential photoreactor and a rotational central composite design (RCCD) was employed for a systematic evaluation and optimization of the operational parameters. The experimental parameters considered were CO₂ flow rate, light intensity, partial pressure of H₂O, and amount of photocatalyst. The synthesized Bi₂WO₆ was characterized by XRD, XPS, Raman, SEM, BET measurements and UV–vis spectroscopy. The results showed that the CO₂ flow rate had an impact on CO₂ photoreduction; the light intensity, partial pressure of H₂O, and amount of photocatalyst significantly influenced the CO cumulative production. At optimum conditions (120 mW cm⁻², 2.7 kPa, and 15 mg), it was possible to obtain a 60% enhancement in photocatalytic efficiency, compared to the results obtained before the experimental design. Characterization studies carried out after the use of the photocatalyst showed that Bi₂WO₆ experienced changes on its surface, which may explain the deactivation observed during the photoreduction under gaseous flow.

二氧化碳（CO ₂）的光还原是一个复杂的过程，尽管在光催化剂的开发上付出了巨大的努力，但是仍然有必要研究过程参数对光还原的影响。在这项工作中，Bi ₂ WO ₆光催化剂用于在连续流差动光反应器中光催化还原CO ₂，旋转中心复合设计（RCCD）用于系统评估和优化操作参数。考虑的实验参数是CO ₂流量，光强度，H ₂ O的分压和光催化剂的量。合成的Bi ₂ WO ₆通过XRD，XPS，拉曼，SEM，BET测量和紫外可见光谱进行表征。结果表明，CO ₂流量对CO _2的光还原有影响。光强度，H ₂ O的分压和光催化剂的量显着影响了CO的累积产生。在最佳条件下（120毫瓦厘米^-2，2.7千帕和15毫克），这是能够得到的光催化效率的60％的增强，相对于实验设计之前所获得的结果。使用光催化剂后进行的表征研究表明，Bi ₂ WO ₆ 经历了表面的变化，这可以解释在气流下光还原过程中观察到的失活。