Induce (101) plane exposure boosting photocatalytic CO₂ reduction in aerobic environment for NH₂-MIL-125

NH₂-MIL-125 with abundant porosity and specific interactions with CO₂ molecules, has been demonstrate great potential in the field of photocatalytic CO₂ reduction. However, conventional NH₂-MIL-125 and their composites much lower CO₂ photoreduction efficiency in aerobic environments because of the O₂ competition. To circumvent the issue, this study modifies NH₂-MIL-125 through crystal facet engineering to enhance its selective CO₂ adsorption and photocatalytic efficiency in the environment of impurity CO₂. The results indicate that NH₂-MIL-125 featuring (101) crystal planes can sustain elevated catalytic activity in low-concentration CO₂ environments. In a pure CO₂ atmosphere, NM-5 achieves a CO production rate of 159.66 μmol·g ^-1 after 4 h, 1.85 times greater than the unmodified NH₂-MIL-125. Under conditions simulating flue gas (5 % CO₂) and ultra-low CO₂ concentrations (0.15 % CO₂), NM-5 maintains CO production rates of 3.18 μmol·g ^-1 and 0.95 μmol·g ^-1, respectively, representing 1.63 and 1.73 times the production rates of NM. Furthermore, theoretical calculations indicate that CO₂ exhibits a higher adsorption energy (-1.34 eV) compared to N₂ and O₂ (-0.67 eV and -0.15 eV) on the (101) crystal plane, which reveals the preferential adsorption of CO₂ on the (101) crystal planes. This study involves a novel strategy for optimizing MOFs crystal planes and provides significant insights into achieving efficient photocatalytic CO₂ reduction under aerobic conditions.