Reactive adsorption of hydrogen sulfide by promoted sorbents Cu‐ZnO/SiO 2 : active sites by experiment and simulation

In the Cu x ‐Zn (1‐x) O/SiO 2 sorbents for ultradeep adsorptive removal of H 2 S from gaseous fuel reformates for fuel cells at room temperature, Cu promoter sites significantly increase sulfur uptake capacity of the sorbents. We report characterization of the family of Cu x ‐Zn (1‐x) O/SiO 2 sorbents for reactive adsorption of H 2 S using X‐ray diffraction (XRD), Brunauer‐Emmett‐Teller (BET) surface area analysis, electron spin resonance (ESR), ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy (DRS) and calculations by the density functional theory (DFT). Both the supported ZnO phase and Cu promoter sites in the Cu x ‐Zn (1‐x) O/SiO 2 sorbents are nano‐dispersed, as shown by XRD. The Cu x ‐Zn (1‐x) O/SiO 2 sorbents contain Cu promoter as the Cu 2+ site of octahedral geometry, as found by the complementary ESR and UV–vis DRS. Mechanism of the promoter effect of the Cu 2+ site in the Cu x ‐Zn (1‐x) O/SiO 2 sorbents in reaction with H 2 S is proposed based on DFT calculations.