Reducing CO₂ to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO₂ emissions and addressing resource depletion. Nevertheless, severe charge recombination and the high energy barrier for CO₂ photoreduction on the surface of photocatalysts compromise the catalytic performance. Herein, a 2D/2D Bi₂MoO₆/BiOI composite was fabricated to achieve improved CO₂ photoreduction efficiency. Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large-area interface. Work function calculation demonstrated that S-scheme charge transfer is operative in the composite, and effective charge separation and strong redox capability were revealed by time-resolved photoluminescence and electron paramagnetic resonance spectroscopy. Moreover, the intermediates of CO₂ photoreduction were identified based on the in situ diffuse reflectance infrared Fourier-transform spectra. Density functional theory calculations showed that CO₂ hydrogenation is the rate-determining step for yielding CH₄ and CO. Introducing Bi₂MoO₆ into the composite further decreased the energy barrier for CO₂ photoreduction on BiOI by 0.35 eV. This study verifies the synergistic effect of the S-scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.

通过太阳辐照将CO _{2还原为碳氢化合物燃料为减少过量CO 2}排放和解决资源枯竭问题提供了可行的途径。_{然而，光催化剂表面严重的电荷复合和CO 2}光还原的高能垒损害了催化性能。在此，制备了 2D/2D Bi ₂ MoO ₆ /BiOI 复合材料以实现改进的 CO ₂光还原效率。具有大面积界面的范德华异质结促进了复合材料中的电荷转移。功函数计算表明，S型电荷转移在复合材料中有效，时间分辨光致发光和电子顺磁共振光谱显示有效的电荷分离和强的氧化还原能力。此外，基于原位漫反射红外傅里叶变换光谱鉴定了CO _{2光还原的中间体。}密度泛函理论计算表明，CO ₂加氢是生成 CH ₄和 CO 的速率决定步骤。引入 Bi ₂ MoO ₆进入复合材料进一步降低了BiOI上CO _{2光还原的能垒0.35 eV。}本研究验证了 S 型异质结和范德华异质结在 2D/2D 复合材料中的协同作用。