CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

Abstract

A conservative CO2-Methanol (CH3OH) regeneration cycle, to capture and reutilize the greenhouse gas of CO2 by aqueous hydrogenation for industry-useful CH3OH and to convert aqueous CH3OH 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 CH3OH yield of 21.1 mmol·g−1catal.·h−1 in the CuMnOS-CO2-H2O system and the other [Cu+]-low one had a H2 yield of 7.65 mmol·g−1catal.·h−1 in the CuMnOS-CH3OH-H2O 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 CH3OH in aqueous solution is not only a fuel but also an ideal liquid hydrogen storage system for transportation application.

Selective Catalytic Reduction of NOx with NH3 over Mn2O3 supported with different morphology of CeO2 Catalysts

“…As seen in Figure3(C), the Mn 2p region consists of two peaks, Mn 2p3/2 with binding energy (BE) of approximately 643.7 eV and Mn2p1/2 with a binding energy of about 655.3 eV which are made up of Mn 4+ and Mn 3+ , indicating that Mn is in the mixed-valence state that is in Mn 3+ and Mn 4+ form 30,31,32 . For three catalysts, the Mn 3+ /(Mn 3+ +Mn 4+ ) content ratio is calculated and found that Mn 2 O 3 /CeO 2 -NP has highest Mn 4+ contents.…”

Tubular bimetal oxysulfide CuMgOS catalyst for rapid reduction of heavy metals and organic dyes

“…prepared Cu‐doped ZnOS oxysulfide alloy films with high hole concentration of 4.3 × 10 19 cm −3 and its applications in spintronic devices. In our previous work, Cu Ni OS, Cu In OS, Zn Ni OS, Cu Mn OS and Cu Ni SeS catalysts were synthesized for reduction of 4‐nitrophenol with NaBH 4 , reduction of Cr (VI) under dark, hydrogen evolution under lower‐power UV light, or degradation of methylene blue (MB) in the dark . Comparing with other component metals, the bimetal oxysulfide catalysts displayed excellent catalytic activity, which can be contributed to the synergistic effect between the constituents and the additional degrees of freedom to boost its catalytic performance .…”

Abiotic Synthesis with the C-C Bond Formation in Ethanol from CO2 over (Cu,M)(O,S) Catalysts with M = Ni, Sn, and Co

“…Abiotic chemical synthesis without the driving force of external inputs in heat, light, and electricity can be a challenge. A preliminary study on the CO 2 /MeOH/H 2 cycle by (Cu, Mn )(O,S) nanoflowers had been presented 28 . Here with lattice strain energy to replace sunlight energy as the driving force to weaken chemical bonds, our aqueous (Cu, M )(O,S) catalyst system with M = Ni, Sn, and Co is demonstrated to produce EtOH from the dissolved CO 2 and water with the C-C bond formation at normal temperature and pressure.…”

“…For the catalyst preparation 28 , 29 , 4.8 g cupric nitrate (Cu(NO 3 ) 2 ·2.5H 2 O) was added to a 500 ml deionized water solution, and then 3 g NiCl 2 ·6H 2 O, SnCl 2 · x H 2 O, or CoCl 2 for the second metal was mixed into the solution. After stirring for 30 min, 1.5 g thioacetamide (CH 3 CSNH 2 ) was added into the mixed solution for another 30 min stirring.…”