CuMnOS nanoflowers with different Cu+ /Cu2+ Ratios for the CO2 -to-CH3 OH and the CH3 OH-to-H2 redox reactions

Abstract

A conservative CO2 -Methanol (CH3 OH) regeneration cycle, to capture and reutilize the greenhouse gas of CO2 by aqueous hydrogenation for industry-useful CH3 OH and to convert aqueous CH3 OH solution by dehydrogenation for the clean energy of hydrogen (H2), is demonstrated at normal temperature and pressure (NTP) with two kinds of CuMnOS nanoflower catalysts. The [Cu+ ]-high CuMnOS led to a CH3 OH yield of 21.1 mmol·g-1 catal.·h-1 in the CuMnOS-CO2 -H2 O system and the other [Cu+ ]-low one had a H2 yield of 7.65 mmol·g-1 catal.·h-1 in the CuMnOS-CH3 OH-H2 O system. The successful redox reactions at NTP rely on active lattice oxygen of CuMnOS catalysts and its charge (hole or electron) transfer ability between Cu+ and Cu2+. The CO2 -hydrogenated CH3 OH in aqueous solution is not only a fuel but also an ideal liquid hydrogen storage system for transportation application.