Promoting Effect of Pd Nanoparticles on SrTi 0.8 Mn 0.2 O 3 in the Reverse Water‐Gas Shift Reaction via the Mars–Van Krevelen Mechanism

Abstract The reverse water‐gas shift (RWGS) reaction serves as a critical pathway for converting CO 2 into diverse chemicals. The Mars–van Krevelen (MvK) mechanism, which leverages lattice oxygen as the oxidant and oxygen vacancies as reductants, offers an alternative catalytic strategy for the selective RWGS reaction. While Mn‐substituted SrTiO 3 (i. e., SrTi 0.8 Mn 0.2 O 3 ) has been shown to promote the RWGS reaction selectively via the MvK mechanism, achieving a sufficient conversion of CO 2 necessitates elevated temperatures. This study investigated the effect of Pd‐loaded SrTi 0.8 Mn 0.2 O 3 on the activation of adsorbed H 2 molecules, which generated oxygen vacancies and enhanced CO 2 conversion. Notably, 1.0 wt % Pd‐loaded SrTi 0.8 Mn 0.2 O 3 yielded 13.4 % of CO at 673 K, whereas pristine SrTi 0.8 Mn 0.2 O 3 and Pd‐loaded SrTiO 3 yielded negligible or minimal amount of CO. Hydrogen temperature‐programmed reduction and X‐ray absorption spectroscopy measurements revealed that Pd promoted the formation of oxygen vacancies via both thermodynamic and kinetic mechanisms. Fourier transform infrared spectroscopy and kinetic studies revealed that the RWGS reaction over Pd‐loaded SrTi 0.8 Mn 0.2 O 3 proceeded primarily via the MvK mechanism with a partial contribution from the Langmuir–Hinshelwood mechanism. This study underscores the effectiveness of combining metal and MvK‐type catalysts to enhance the efficiency of the RWGS reaction.