Efficient water gas shift reaction by a novel Pt single atoms anchored on SBA-15-derived SmCoO3/GO catalyst

xPtSSG (xPtSmCoO3/SBA-15/GO, x = 0.37, 0.83 and 0.88) was prepared via deposition–precipitation and polyvinyl alcohol-protected reduction method, and the catalytic activity was evaluated by the CO conversion of water gas shift (WGS). The crystal structure and physicochemical properties of the catalysts were evaluated by numerous techniques. Pt species were present as single atoms or/and nanoparticles over xPtSSG samples. Graphene oxide (GO) as an electron transfer bridge could significantly strengthen the strong metal-support interaction (SMSI) between Pt and SSG, thus significantly enhancing catalytic activity. Among all the samples, the lower Pt-loading single atom Pt 0.37PtSSG sample had the highest specific rate (0.84 molCO gPt-1) and TOF (4.5 × 10-2 s−1 at 250 °C), which may be due to the higher oxidation state of Pt species (3.39) via Co-PtOx, high Oads/Olat molar ratio and good low-temperature reducibility. The DRIFTS demonstrates that CO2 was produced by the redox mechanism between CO and oxygen species over single atom Pt 0.37PtSSG catalyst. However, CO reacted with OH by associative mechanism to produce formate or carboxylate intermediates over the nano-Pt 0.88PtSSG sample. By DFT calculation of CO adsorption over the (0 2 0) crystal plane of perovskite, the adsorption energy on Pt single atoms was significantly lower than that of Pt nanoparticles, thus confirming the catalytic activity of Pt single atoms was higher than that of Pt nanoparticles. This work provides an effective approach to designing a high-performance catalyst for water gas shift reaction.