Size-dependent catalytic behavior of MoS2 nanoparticles in water-gas shift reaction

Well-dispersed and uniformly sized 5–84 nm Mo oxide and CoMo oxide nanoparticles were synthesized by varying the Mo and Co precursor concentrations. The water-gas shift (WGS) activity of sulfided Mo-based catalysts was found to increase with particle size and in the presence of Co. In particular, 84-nm CoMo-S nanoparticles exhibited 15 times higher effective CO consumption rate and 2.3 times higher turnover frequency (TOF) as compared to 5- nm Mo-S nanoparticles. The observed trends in size-dependent catalytic behavior correlated with the higher density of the proposed active sites present on larger (Co)Mo-S nanoparticles probed by CO chemisorption. •5–84 nm sized (Co)MoOx nanoparticles were synthesized and sulfided•WGS activity of supported (Co)Mo-S nanoparticles increased with their size•Surface active sites present in (Co)Mo-S nanoparticles were probed by CO chemisorption•Size-dependent WGS activity correlated with the density of active sites