Platinum (Pt)-based catalysts often failed to possess high CO₂ conversion and high CO selectivity at the same time (especially at high reaction temperature) in reverse water gas shift (RWGS) reaction. Herein, we found that atomically dispersed Pt species was the crucial factor in improving the selectivity of CO and inhibiting the formation of CH₄. Three Pt/CeO₂ catalysts, including atomically dispersed Pt species, and Pt clusters or particles with different sizes, were synthesized. It was found that the atomically dispersed Pt/CeO₂ catalyst led to an outstanding CO selectivity (>98 %) in the temperature range of 200∼450 °C, while the CO selectivities over Pt nanoparticles decreased conspicuously as the reaction temperature increased. CO-TPD and in situ FTIR experiments demonstrated that CH₄ was produced by the further hydrogenation of CO. And the atomically dispersed Pt species had the relatively weak adsorption strength toward CO, which prevented excessive hydrogenation and promoted CO selectivity in RWGS reaction. Our investigation provides a new thinking for designing the RWGS reaction catalyst with an outstanding CO selectivity and emphasize the significance of atomically dispersed catalysts in catalytic reactions again.

铂（Pt）基催化剂在逆水煤气变换（RWGS）反应中通常同时（尤其是在高反应温度下）不能具有高CO ₂转化率和高CO选择性。在本文中，我们发现原子分散的Pt物种是提高CO的选择性和抑制CH ₄形成的关键因素。合成了三种Pt / CeO ₂催化剂，包括原子分散的Pt物种，不同尺寸的Pt簇或颗粒。发现原子分散的Pt / CeO ₂催化剂在200〜450°C的温度范围内具有出色的CO选择性（> 98％），而随着反应温度的升高，Pt纳米颗粒上的CO选择性显着下降。CO-TPD和原位FTIR实验表明，CH ₄是由CO的进一步加氢产生的。原子分散的Pt物种对CO的吸附强度较弱，从而防止了过度氢化，并提高了RWGS反应中的CO选择性。我们的研究为设计具有出色的CO选择性的RWGS反应催化剂提供了新思路，并再次强调了原子分散催化剂在催化反应中的重要性。