Regulating the selectivity between CO and CH₄ during CO₂ hydrogenation is a challenging research topic. Previous research has indicated that potassium (K) modification can adjust the product selectivity by regulating the adsorption strength of formate/CO* intermediates. Going beyond the regulation mechanism described above, this study proposes a K-guided selectivity control method based on the regulation of key intermediates HCO*/H₃CO* for Ni catalysts supported on reducible carrier CeO₂. By incorporating K, the CO selectivity of CO₂ hydrogenation shifts from around 25.4% for Ni/CeO₂ to approximately 93.8% for Ni/CeO₂-K. This can be attributed to K modification causes electron aggregation in the bonding regions of HCO* and H₃CO* intermediates, thus enhancing their adsorption strength. Consequently, the reaction pathway from HCO*/H₃CO* to CH₄ is limited, favoring the decomposition of formates to CO products. Moreover, the addition of K leads to a moderate decrease in CO₂ conversion from 55.2% to 48.6%, which still surpasses values reported in most other studies. This reduction is associated with a decline in reducible Ni species and oxygen vacancy concentration in Ni/CeO₂-K. As a result, the adsorption capacity for CO₂ and H₂ reduces, ultimately reducing CO₂ hydrogenation activity.

调节CO ₂加氢过程中CO和CH ₄之间的选择性是一个具有挑战性的研究课题。先前的研究表明，钾（K）改性可以通过调节甲酸盐/CO*中间体的吸附强度来调节产物选择性。超越上述调节机制，本研究提出了一种基于关键中间体HCO*/H ₃ CO*调节的K引导选择性控制方法，用于可还原载体CeO ₂负载的Ni催化剂。通过掺入K，CO ₂加氢的CO选择性从Ni/CeO ₂的约25.4％转变为Ni/CeO ₂ -K的约93.8％。这可以归因于K改性导致HCO*和H ₃ CO*中间体的键合区域中的电子聚集，从而增强了它们的吸附强度。因此，从HCO*/H ₃ CO*到CH ₄的反应途径受到限制，有利于甲酸盐分解为CO产物。此外，K的添加导致CO ₂转化率从55.2%适度下降至48.6%，这仍然超过大多数其他研究报告的值。这种减少与Ni/CeO ₂ -K中可还原Ni物质和氧空位浓度的下降相关。结果，CO ₂和H ₂的吸附能力降低，最终降低CO ₂加氢活性。