Mesoporous silica “plated” copper hydroxides/oxides heterostructures as superior regenerable sorbents for low temperature H2S removal

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Metal oxides exhibit highest adsorption capacities towards H2S but are challenged by lack of regenerability due to sulfide layer formation during adsorption, sulfate phase formation during regeneration, sintering, spalling, and sublimation. Protection strategies such as supporting the metal oxide may mitigate such problems but comes at the expense of the regenerable capacity. Herein, we present a methodology for the synthesis of heterostructures comprised of CuO encapsulated by an ultra-thin mesoporous SiO2 matrix, starting from nanoparticles of Cu(OH)2 as the intermediate seeds of CuO and by using a surfactant based method for the silica encapsulation. Upon calcination, a complex pore structure arises due to the removal of the surfactant and the shrinkage of the intermediate seeding nanoparticles (Cu(OH)2 to CuO). The sorbents achieved high regenerable sulfur capacity, up to 10 mmol/gCuO due to the high CuO content, and combination of large interconnected macro/meso-cavities (~40–50 nm). Those attributes confer a regenerable H2S adsorption capacity that is unprecedented in the literature to the best of our knowledge especially considering the relatively low testing temperature and high space velocity (150 °C, 300,000 h−1). The methodology presented herein can be extended to other gas–solid reactive sorption-based systems as in carbon capture.