Measurement of intrinsic catalytic activity of Pt monometallic and Pt-MoOx interfacial sites over visible light enhanced PtMoOx/SiO2 catalyst in reverse water gas shift reaction

Abstract Supported Pt-Mo catalysts were prepared with different Mo contents by a controlled surface reaction (CSR) method and studied for the reverse water gas shift (RWGS) reaction under dark and visible light irradiation conditions. Characterization results from Raman spectroscopy, scanning transmission electron microscopy (STEM), CO chemisorption, and inductively coupled plasma-absorption emission spectroscopy (ICP-AES) indicate that selective Mo deposition onto Pt was achieved at low Mo loading (Mo/Pt ratio  2 and CO reaction orders. Visible light irradiation changed the apparent activation energy and reaction orders of CO 2 , CO, and H 2 , ascribed to direct photoexcitation. The intrinsic activity of a Pt site is 0.4 and 4.1 min −1 under dark and light conditions at 473 K, respectively, whereas the intrinsic activity of a Pt-MoO x site is increased to 22.7 and 160 min −1 under dark and light conditions at 473 K, respectively.