Carbon nanoflake hybrid for biohydrogen CO2 capture: Breakthrough adsorption test

Biohydrogen gas is a hot topic for H-2 fuel at present. However, removal of the unwanted CO2 through adsorption is required before any system is supplied with high-purity H-2 gas. Herein, we prepared a novel carbon nanoflake hybrid for efficient biohydrogen CO2 capture by combining the advantages of carbon, metal oxide, and amine. Among the samples, SH800 showed a remarkable high CO2 adsorption capacity of 29.8 wt.% (6.77 mmol/g) at 25 degrees C and 1 atm, the highest ever reported at low pressure and temperature. The regeneration experiment also demonstrated robust reversibility over five cycles in the absence of heat treatment. Moreover, it displayed a highly accessible adsorption site with a Brunauer-Emmett-Teller (BET) surface area of 600 m(2)/g and an optimal 6.6-nm average mesopore structure. Another hybrid named SH500 was also developed. This hybrid showed a comparable CO2 uptake of 27.8 wt.%, being competitive to SH800 but with entirely different chemical properties. Both samples were analyzed by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy, (XPS) and were tested for CO2 capture through a breakthrough experiment. A highly porous solid adsorbent was also produced via soft-template synthesis. In summary, the correct amount of dynamic factors, such as high surface area, mesopore-micropore morphology, activation temperature, metal hybridization, and N moieties, played a major role in the carbon engineering of CO2 adsorbent.