Ni-functionalized Ca@Si yolk-shell nanoreactors for enhanced integrated CO2 capture and dry reforming of methane via confined catalysis

The emerging integrated CO2 capture and utilization (ICCU) potentially contributes to net zero emissions with low cost and high efficiency. The catalytic performance in ICCU process is highly restricted by the equilibriums of carbonate decomposition and dry reforming of methane (DRM). Here, we engineer a unique yolk-shell dual functional nanoreactor construction to improve the catalytic performance via confined catalysis. By tailoring the carbonates decomposition kinetics and confining the CO2 diffusion path, ∼92% CO2 conversion is achieved over (Ni/Ca)@Si and shows no distinct activity loss in 10 cycles at 650 °C. The formed Ca2SiO4 shells restrain the sintering of CaO yolks by acting as physical barriers, and stabilize the Ni particle size. It is also confirmed on in situ DRIFTS that the integrated DRM might occur via carbonyls, formates and CHO intermediates, in which formates species are highly dependent on Ni-carbonates interfaces.